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第7篇：聚合、继承、裁剪详解
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<div style="display:none"></div> **maven系列目标：从入门开始开始掌握一个高级开发所需要的maven技能。** 这是maven系列第7篇。 **整个maven系列的内容前后是有依赖的，如果之前没有接触过maven，建议从第一篇看起，本文尾部有maven完整系列的连接。** ## 本篇内容 1. maven中聚合详解 2. maven中继承详解 3. pom.xml中parent元素的使用详解 4. pom.xml中dependencyManagement元素使用详解 5. pom.xml中pluginManagement元素使用详解 6. 单继承存在的问题及解决方案详解（springboot,springcloud中会常用） 8. 解答上一篇遗留的2个问题 ## 聚合 ### 原始需求 我们需要使用java做一个电商网站，涉及到：pc端网站、h5微站、移动端接口部分，那么我们可以使用maven创建3个项目用于这3块业务的开发，3个项目名称如下： ```java javacode2018-pc javacode2018-h5 javacode2018-api ``` 这3个项目的groupId都是`com.javacode2018`，artifactId取上面的，我们使用maven来搭建项目结构。 ### 实现 #### 创建第一个javacode2018-pc项目 打开idea，点击`File->New->Project`，选择`Maven`，如下：  点击`Next`，输入项目坐标信息，如下：  点击`Next`，输入Project name 为`javacode2018-pc`，如下：  点击`Finish`，创建成功，如下：  配置一下idea的maven环境，点击`File->Settings`，如下图：  点击上面的`OK`完成配置。 大家再按照上面一样的操作，分别创建另外2个项目`javacode2018-h5`和`javacode2018-api`，创建完成之后，另外2个项目如下图：   上面3个项目由整个项目组6个人共同开发，这几个项目经常一起上线，上线过程，先由开发进行打包，然后将几个包发给运行进行发布。我们使用`mvn package`进行打包，需要在每个项目的`pom.xml`所在目录都去执行一次这个命令，也就是说需要执行3次，这个电商项目还会涉及到后台系统、bi系统、监控系统等等，可能最后会多达10个小项目，那时候我们每次上线都需要执行10次打包操作，这个过程是相当繁琐的。 那么maven有没有更好的办法来解决这个事情呢？ 这个用到的就是我们本次要说的`maven中的聚合`。 整个电商我们可以作为一个大的系统，上面的pc端、h5微站、api接口、后台系统、bi系统、监控系统都可以作为里面的一个具体比较大一个模块。 我们使用`maven聚合`功能来实现上面的需求，我们需要创建一个额外的maven项目`javacode-aggregator`来管理上面3个项目，然后只用在`javacode-aggregator`项目中执行`mvn`命令，就会自动为其他3个项目自动执行同样的`mvn`命令。 ### Maven聚合 maven聚合需要创建一个新的maven项目， 用来管理其他的maven构件模块，新的maven项目中加入如下配置： ```xml <modules> <module>模块1</module> <module>模块2</module> <module>模块n</module> </modules> <package>pom</package> ``` > 新的项目中执行任何`mvn`命令，都会`modules`中包含的所有模块执行同样的命令，而被包含的模块不需要做任何特殊的配置，正常的maven项目就行。 > > 注意上面的`module`元素，这部分是被聚合的模块`pom.xml`所在目录的相对路径。 > > package的值必须为pom，这个需要注意。 > > 下面看案例。 ### 实操案例 > 下面过程仔细看了。 #### 创建项目javacode-aggregator 打开idea，点击`File->New->Project`，选择`Maven`，如下：  点击`Next`，输入项目坐标信息，如下：  点击`Next`，输入Project name 为`javacode-aggregator`，如下：  点击`Finish`，创建成功，如下：  配置一下idea的maven环境，点击`File->Settings`，如下图：  删除下面无用的代码：  项目变成了下面这样：  `pom.xml`中加入下面配置： ```xml <packaging>pom</packaging> ``` 最后pom.xml内容如下： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.javacode2018</groupId> <artifactId>javacode-aggregator</artifactId> <version>1.0-SNAPSHOT</version> <packaging>pom</packaging> </project> ``` #### 创建javacode2018-pc模块 **注意这里说的是模块，不再是创建项目，过程仔细看。** idea中选中`javacode-aggregator`  点击`File->New->Module`，准备创建模块，如下图：  选择`Maven`，如图：  点击`Next`，如下：  点击下面的`...`按钮，选择`None`，如下：    输入坐标信息，如下：  点击`Next`，输入Module name :`javacode2018-pc`，如下：  点击`Finish`，完成`javacode-2018`模块的创建，如下：  我们来看一下`javacode-aggregator`的pom.xml，多了一部分，如下：  > 注意上面的`<packaging>pom</packaging>` #### 创建javacode2018-h5模块 创建步骤和上面`javacode2018-pc`步骤一样。 #### 创建javacode2018-api模块 创建步骤和上面`javacode2018-pc`步骤一样。 我们看一下项目最终结构，如下图：  看一下上图中的`javacode-aggregator`项目的`pom.xml`，`modules`元素中多出了3部分。 再来看看其他3个模块的pom文件，和普通的pom.xml一样，如下图：    在`javacode-aggregator/pom.xml`目录中执行`mvn package`感受一下效果： ```java D:\code\IdeaProjects\javacode-aggregator>mvn package [INFO] Scanning for projects... [INFO] ------------------------------------------------------------------------ [INFO] Reactor Build Order: [INFO] [INFO] javacode2018-pc [jar] [INFO] javacode2018-h5 [jar] [INFO] javacode2018-api [jar] [INFO] javacode-aggregator [pom] [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------ [INFO] Building javacode2018-pc 1.0-SNAPSHOT [1/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode-aggregator\javacode2018-pc\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-pc --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-pc --- [INFO] Building jar: D:\code\IdeaProjects\javacode-aggregator\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] [INFO] ------------------< com.javacode2018:javacode2018-h5 >------------------ [INFO] Building javacode2018-h5 1.0-SNAPSHOT [2/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-h5 --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-h5 --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-h5 --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode-aggregator\javacode2018-h5\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-h5 --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-h5 --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-h5 --- [INFO] Building jar: D:\code\IdeaProjects\javacode-aggregator\javacode2018-h5\target\javacode2018-h5-1.0-SNAPSHOT.jar [INFO] [INFO] -----------------< com.javacode2018:javacode2018-api >------------------ [INFO] Building javacode2018-api 1.0-SNAPSHOT [3/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-api --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-api --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-api --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode-aggregator\javacode2018-api\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-api --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-api --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-api --- [INFO] Building jar: D:\code\IdeaProjects\javacode-aggregator\javacode2018-api\target\javacode2018-api-1.0-SNAPSHOT.jar [INFO] [INFO] ----------------< com.javacode2018:javacode-aggregator >---------------- [INFO] Building javacode-aggregator 1.0-SNAPSHOT [4/4] [INFO] --------------------------------[ pom ]--------------------------------- [INFO] ------------------------------------------------------------------------ [INFO] Reactor Summary for javacode-aggregator 1.0-SNAPSHOT: [INFO] [INFO] javacode2018-pc .................................... SUCCESS [ 2.542 s] [INFO] javacode2018-h5 .................................... SUCCESS [ 0.195 s] [INFO] javacode2018-api ................................... SUCCESS [ 0.218 s] [INFO] javacode-aggregator ................................ SUCCESS [ 0.024 s] [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3.223 s [INFO] Finished at: 2019-11-19T13:28:00+08:00 [INFO] ------------------------------------------------------------------------ ``` 我们分析一下上面的输出： ```java [INFO] Reactor Build Order: [INFO] [INFO] javacode2018-pc [jar] [INFO] javacode2018-h5 [jar] [INFO] javacode2018-api [jar] [INFO] javacode-aggregator [pom] ``` > 上面这个列出了需要构件的maven构件列表及顺序，共有4个构件，3个jar包，1个pom类型的构件。 然后开始按照上面列出的顺序，一个个开始执行`mvn package`命令，最后4个都执行成功了，我们来看一下最终产生的效果，如下图：  从上图中我们可以看到3个模块都生成了jar包，说明我们执行了一次`mvn package`，分别在3个模块中都运行了，我们在来执行一下`mvn clean`清理代码，感受一下最终效果： ``` D:\code\IdeaProjects\javacode-aggregator>mvn clean [INFO] Scanning for projects... [INFO] ------------------------------------------------------------------------ [INFO] Reactor Build Order: [INFO] [INFO] javacode2018-pc [jar] [INFO] javacode2018-h5 [jar] [INFO] javacode2018-api [jar] [INFO] javacode-aggregator [pom] [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------ [INFO] Building javacode2018-pc 1.0-SNAPSHOT [1/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode2018-pc --- [INFO] Deleting D:\code\IdeaProjects\javacode-aggregator\javacode2018-pc\target [INFO] [INFO] ------------------< com.javacode2018:javacode2018-h5 >------------------ [INFO] Building javacode2018-h5 1.0-SNAPSHOT [2/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode2018-h5 --- [INFO] Deleting D:\code\IdeaProjects\javacode-aggregator\javacode2018-h5\target [INFO] [INFO] -----------------< com.javacode2018:javacode2018-api >------------------ [INFO] Building javacode2018-api 1.0-SNAPSHOT [3/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode2018-api --- [INFO] Deleting D:\code\IdeaProjects\javacode-aggregator\javacode2018-api\target [INFO] [INFO] ----------------< com.javacode2018:javacode-aggregator >---------------- [INFO] Building javacode-aggregator 1.0-SNAPSHOT [4/4] [INFO] --------------------------------[ pom ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode-aggregator --- [INFO] ------------------------------------------------------------------------ [INFO] Reactor Summary for javacode-aggregator 1.0-SNAPSHOT: [INFO] [INFO] javacode2018-pc .................................... SUCCESS [ 0.250 s] [INFO] javacode2018-h5 .................................... SUCCESS [ 0.067 s] [INFO] javacode2018-api ................................... SUCCESS [ 0.068 s] [INFO] javacode-aggregator ................................ SUCCESS [ 0.034 s] [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 0.605 s [INFO] Finished at: 2019-11-19T13:34:42+08:00 [INFO] ------------------------------------------------------------------------ ``` 项目结构如下图：  3个项目中的target都被清理掉了，是不是感觉很爽。 **上面介绍了pom.xml中的`module`元素的值为被聚合的模块pom.xml所在的目录路径，只能是相对路径，比如下面这样** ```xml <modules> <module>zipkin-server-source-demo</module> <module>../../../tmp/child-project</module> <module>../../../tmp/child-project/pom.xml</module> </modules> ``` 聚合的功能中，聚合模块的pom.xml中通过`modules->module`来引用被聚合的模块，被聚合的模块是不用感知自己被聚合了，所以被聚合的模块中`pom.xml`中是不知道`javacode-aggregator`的存在的。 ## 继承 ### 需求 细心的朋友已经发现了`javacode2018-pc、javacode2018-h5、javacode2018-api`3个项目的`groupId、version`都是一样的。还有这几个项目准备都是用springmvc、mybatis开发的，所以需要引入依赖如下： ```xml <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>5.2.1.RELEASE</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>2.0.3</version> </dependency> ``` 3个项目中出现了同样的配置，一个配置出现了多份，作为开发者，我想你们和我一样，是无法接受的，必须要寻求一些方法来解决，需要将公共的部分提取出来共用。 maven也为我们考虑到了这种情况，maven中使用继承来解决这个问题。 ### 继承的实现 操作分为3步骤： 1. 创建一个父maven构件，将依赖信息放在pom.xml中 ```xml <dependencies> <dependency>依赖的构件的坐标信息</dependency> <dependency>依赖的构件的坐标信息</dependency> <dependency>依赖的构件的坐标信息</dependency> </dependencies> ``` 2. 将父构件的package元素的值置为pom ```xml <packaging>pom</packaging> ``` 3. 在子构件的pom.xml引入父构件的配置： ```xml <parent> <groupId>父构件groupId</groupId> <artifactId>父构件artifactId</artifactId> <version>父构件的版本号</version> <relativePath>父构件pom.xml路径</relativePath> </parent> ``` > relativePath表示父构件pom.xml相对路径，默认是`../pom.xml`，所以一般情况下父子结构的maven构件在目录结构上一般也采用父子关系。 ### 实操案例 先创建一个父项目`javacode-parent`，坐标信息如下： ```xml <groupId>com.javacode2018</groupId> <artifactId>javacode2018-parent</artifactId> <version>1.0-SNAPSHOT</version> ``` 创建过程大家已经轻车熟路了，就不演示了，最终如下图：  删除无用的2目录`.idea和src`  #### 创建子模块javacode2018-pc **注意这里说的是模块了，不在是创建项目了，过程仔细看。** idea中选中`javacode-parent`，如下图：  点击`File->New->Module`，准备创建模块，如下图：  选中`Maven`，如下图：  点击`Next`，这个页面需要注意了，默认如下图：  此时我们点击第一个`...`按钮，这个按钮是设置聚合的，所以选中`None`，如下图：   变成了下面这样：  输入构件信息，如下图：  点击`Next`，输入`Module-name`的值为`javacode2018-pc`，如下图：  点击`Finish`完成创建操作，如下图：  上图中，看一下`javacode2018-pc`的pom.xml，多了个`parent`元素，并且这个pom.xml中构件的`groupId、version`都没有了，这个`pom.xml`继承了`javacode2018-parent/pom.xml`中的内容，他们的`groupId、version`都是一样的，子构件可以从父pom.xml中继承这些内容，所以如果是一样的情况，可以不写。 #### 创建另外两个子模块javacode2018-h5、javacode2018-api 步骤参考`javacode2018-pc`模块的创建过程。 最终项目如下图：  下面我们来看一下4个pom.xml的内容。 javacode2018-parent/pom.xml的内容： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.javacode2018</groupId> <artifactId>javacode2018-parent</artifactId> <version>1.0-SNAPSHOT</version> </project> ``` javacode2018-pc/pom.xml的内容： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <artifactId>javacode2018-parent</artifactId> <groupId>com.javacode2018</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>javacode2018-pc</artifactId> </project> ``` javacode2018-h5/pom.xml的内容： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <artifactId>javacode2018-parent</artifactId> <groupId>com.javacode2018</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>javacode2018-h5</artifactId> </project> ``` javacode2018-api/pom.xml的内容： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <artifactId>javacode2018-parent</artifactId> <groupId>com.javacode2018</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>javacode2018-api</artifactId> </project> ``` 我们在父构件javacode2018-parent/pom.xml中加入下面配置： ```xml <packaging>pom</packaging> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>5.2.1.RELEASE</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>2.0.3</version> </dependency> </dependencies> ``` 使用下面命令在javacode2018-parent/pom.xml所在目录看一下javacode2018-parent构件依赖情况: ```java D:\code\IdeaProjects\javacode2018-parent>mvn dependency:tree [INFO] Scanning for projects... [INFO] [INFO] ----------------< com.javacode2018:javacode2018-parent >----------------- [INFO] Building javacode2018-parent 1.0-SNAPSHOT [INFO] --------------------------------[ pom ]--------------------------------- [INFO] [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ javacode2018-parent --- [INFO] com.javacode2018:javacode2018-parent:pom:1.0-SNAPSHOT [INFO] +- org.springframework:spring-web:jar:5.2.1.RELEASE:compile [INFO] | +- org.springframework:spring-beans:jar:5.2.1.RELEASE:compile [INFO] | \- org.springframework:spring-core:jar:5.2.1.RELEASE:compile [INFO] | \- org.springframework:spring-jcl:jar:5.2.1.RELEASE:compile [INFO] \- org.mybatis:mybatis-spring:jar:2.0.3:compile [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.544 s [INFO] Finished at: 2019-11-19T14:58:21+08:00 [INFO] ------------------------------------------------------------------------ ``` > mvn dependency:tree 这个插件可以根据pom.xml的配置，列出构件的依赖树信息。 我们再来看看javacode2018-pc/pom.xml构件的依赖信息： ```java D:\code\IdeaProjects\javacode2018-parent>cd javacode2018-pc D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc>mvn dependency:tree [INFO] Scanning for projects... [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------- [INFO] Building javacode2018-pc 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ javacode2018-pc --- [INFO] com.javacode2018:javacode2018-pc:jar:1.0-SNAPSHOT [INFO] +- org.springframework:spring-web:jar:5.2.1.RELEASE:compile [INFO] | +- org.springframework:spring-beans:jar:5.2.1.RELEASE:compile [INFO] | \- org.springframework:spring-core:jar:5.2.1.RELEASE:compile [INFO] | \- org.springframework:spring-jcl:jar:5.2.1.RELEASE:compile [INFO] \- org.mybatis:mybatis-spring:jar:2.0.3:compile [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.093 s [INFO] Finished at: 2019-11-19T14:59:34+08:00 [INFO] ------------------------------------------------------------------------ ``` > 从上图中可以看到`javacode2018-pc`依赖的jar和父构件`javacode2019-parent`的一样，说明从父类继承了这些依赖。 > > 其他2个子构件，大家也可以去看一下，依赖关系都从父构件继承过来了。 ### relativePath元素 上面演示的父构件和子构件的目录结构刚好符合父子关系，如果父构件和子构件的目录不是父子关系，比如都位于同等级别的目录或者位于更复杂的目录的时候，此时我们需要在子`pom.xml`的`parent`元素中使用`relativePath`元素来指定父`pom.xml`相对路径位置，这个值我们上面没有指定，默认是`../pom.xml`，表示父pom.xml位于子pom.xml的上一级目录，我们的模块刚好符合这种关系，所以这个值省略了。 正确的设置`relativePath`是非常重要的，这个需要注意，子模块中执行`mvn`命令的时候，会去找父`pom.xml`的配置，会先通过`relativePath`指定的路径去找，如果找不到，会尝试通过坐标在本地仓库进行查找，如果本地找不到，会去远程仓库找，如果远程仓库也没有，会报错。 ### 可以通过继承的元素有以下这些 上面我们看到了`groupId、version、dependency中的依赖`在子`pom.xml`中都没有写，这些都是从父`pom.xml`中继承过来的，还有很多元素也可以被继承过来，下面我们列个清单： - groupId：项目组ID，项目坐标的核心元素 - version：项目版本，项目坐标的核心元素 - description：项目的描述信息 - organization：项目的组织信息 - inceptionYear：项目的创始年份 - url：项目的url地址 - developers：项目的开发者信息 - contributors：项目的贡献者信息 - distributionManagement：项目的部署配置信息 - issueManagement：项目的缺陷跟踪系统信息 - ciManagement：项目的持续集成系统信息 - scm：项目的版本控制系统信息 - mailingLists：项目的邮件列表信息 - properties：自定义的maven属性配置信息 - dependencyManagement：项目的依赖管理配置 - repositories：项目的仓库配置 - build：包括项目的源码目录配置、输出目录配置、插件管理配置等信息 - reporting：包括项目的报告输出目录配置、报告插件配置等信息 ## 依赖管理(dependencyManagement) 大家是否发现了，上面的继承存在的一个问题，如果我在新增一个子构件，都会默认从父构件中继承依赖的一批构建，父pom.xml中配置的这些依赖的构建可能是其他项目不需要的，可能某个子项目只是想使用其中一个构件，但是上面的继承关系却把所有的依赖都给传递到子构件中了，这种显然是不合适的。 maven中也考虑到了这种情况，可以使用`dependencyManagement`元素来解决这个问题。 maven提供的dependencyManagement元素既能让子模块继承到父模块的依赖配置，又能保证子模块依赖使用的灵活性，**在dependencyManagement元素下声明的依赖不会引入实际的依赖，他只是声明了这些依赖，不过它可以对`dependencies`中使用的依赖起到一些约束作用。** 修改`javacode2018-parent/pom.xml`配置如下： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.javacode2018</groupId> <artifactId>javacode2018-parent</artifactId> <version>1.0-SNAPSHOT</version> <packaging>pom</packaging> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>5.2.1.RELEASE</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>2.0.3</version> </dependency> </dependencies> </dependencyManagement> </project> ``` 可以看到我们将`dependencies`配置移到`dependencyManagement`下面了。 我们使用下面命令看一下项目的依赖情况： ```java D:\code\IdeaProjects\javacode2018-parent>mvn dependency:tree [INFO] Scanning for projects... [INFO] [INFO] ----------------< com.javacode2018:javacode2018-parent >----------------- [INFO] Building javacode2018-parent 1.0-SNAPSHOT [INFO] --------------------------------[ pom ]--------------------------------- [INFO] [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ javacode2018-parent --- [INFO] com.javacode2018:javacode2018-parent:pom:1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.756 s [INFO] Finished at: 2019-11-19T15:44:52+08:00 [INFO] ------------------------------------------------------------------------ D:\code\IdeaProjects\javacode2018-parent>cd javacode2018-pc D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc>mvn dependency:tree [INFO] Scanning for projects... [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------- [INFO] Building javacode2018-pc 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ javacode2018-pc --- [INFO] com.javacode2018:javacode2018-pc:jar:1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.676 s [INFO] Finished at: 2019-11-19T15:45:08+08:00 [INFO] ------------------------------------------------------------------------ ``` > 父子构件中都看不到依赖的jar包了，说明父pom.xml中dependencyManagement这些依赖的构建没有被子模块依赖进去。 子模块如果想用到这些配置，可以`dependencies`进行引用，引用之后，依赖才会真正的起效。 在在3个子模块的pom.xml中加入下面配置： ```xml <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> </dependency> </dependencies> ``` 我们在运行一下上面的3个命令，看效果： ```java D:\code\IdeaProjects\javacode2018-parent>mvn dependency:tree [INFO] Scanning for projects... [INFO] [INFO] ----------------< com.javacode2018:javacode2018-parent >----------------- [INFO] Building javacode2018-parent 1.0-SNAPSHOT [INFO] --------------------------------[ pom ]--------------------------------- [INFO] [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ javacode2018-parent --- [INFO] com.javacode2018:javacode2018-parent:pom:1.0-SNAPSHOT [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.759 s [INFO] Finished at: 2019-11-19T15:48:28+08:00 [INFO] ------------------------------------------------------------------------ D:\code\IdeaProjects\javacode2018-parent>cd javacode2018-pc D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc>mvn dependency:tree [INFO] Scanning for projects... [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------- [INFO] Building javacode2018-pc 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-dependency-plugin:2.8:tree (default-cli) @ javacode2018-pc --- [INFO] com.javacode2018:javacode2018-pc:jar:1.0-SNAPSHOT [INFO] +- org.springframework:spring-web:jar:5.2.1.RELEASE:compile [INFO] | +- org.springframework:spring-beans:jar:5.2.1.RELEASE:compile [INFO] | \- org.springframework:spring-core:jar:5.2.1.RELEASE:compile [INFO] | \- org.springframework:spring-jcl:jar:5.2.1.RELEASE:compile [INFO] \- org.mybatis:mybatis-spring:jar:2.0.3:compile [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.875 s [INFO] Finished at: 2019-11-19T15:48:38+08:00 [INFO] ------------------------------------------------------------------------ ``` > javacode2018-parent构件中没有列出依赖信息，而javacode2018-pc列出了依赖信息。 大家看一下下面的截图：  > 注意上面的红框中依赖的构建没有`version`，左边2个红圈中的2个向上的箭头，表示这个是从父pom.xml中传递过来的，所以version可以省略。 再看一下父pom.xml截图效果：  > dependencyManagement中定义了依赖的构建，2个向下的箭头表示被子模块有继承。 **dependencyManagement不会引入实际的依赖，只有在子类中使用`dependency`来引入父`dependencyManagement`声明的依赖之后，依赖的构建才会被真正的引入。** **使用dependencyManagement来解决继承的问题，子pom.xml中只用写`groupId,artifactId`就可以了，其他信息都会从父`dependencyManagement`中声明的依赖关系中传递过来，通常我们使用这种方式将所有依赖的构建在父pom.xml中定义好，子构件中只需要通过`groupId,artifactId`就可以引入依赖的构建，而不需要写`version`，可以很好的确保多个子项目中依赖构件的版本的一致性，对应依赖构件版本的升级也非常方便，只需要在父pom.xml中修改一下就可以了。** ## 单继承问题 ### 存在的问题及解决方案 上面讲解了dependencyManagement的使用，但是有个问题，只有使用继承的时候，dependencyManagement中声明的依赖才可能被子pom.xml用到，如果我的项目本来就有父pom.xml了，但是我现在想使用另外一个项目dependencyManagement中声明的依赖，此时我们怎么办？这就是单继承的问题，这种情况在spring-boot、spring-cloud中会遇到，所以大家需要注意，这块一定需要玩转。 当我们想在项目中使用另外一个构件中dependencyManagement声明的依赖，而又不想继承这个项目的时候，可以在我们的项目中使用加入下面配置： ```xml <dependencyManagement> <dependencies> <dependency> <groupId>com.javacode2018</groupId> <artifactId>javacode2018-parent</artifactId> <version>1.0-SNAPSHOT</version> <type>pom</type> <scope>import</scope> </dependency> <dependency>构件2</dependency> <dependency>构件3</dependency> <dependency>构件n</dependency> </dependencies> </dependencyManagement> ``` > **注意上面有两个关键元素：type的值必须是pom，scope元素的值必须是import** 上面这个配置会将`javacode2018-parent`构件中`dependencyManagement`元素中声明的所有依赖导入到当前pom.xml的`dependencyManagement`中，相当于把下面部分的内容： ```xml <dependency> <groupId>com.javacode2018</groupId> <artifactId>javacode2018-parent</artifactId> <version>1.0-SNAPSHOT</version> <type>pom</type> <scope>import</scope> </dependency> ``` 替换成了`javacode2018-parent/pom.xml`中dependencyManagement元素内容，替换之后变成： ```xml <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>5.2.1.RELEASE</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis-spring</artifactId> <version>2.0.3</version> </dependency> <dependency>构件2</dependency> <dependency>构件3</dependency> <dependency>构件n</dependency> </dependencies> </dependencyManagement> ``` ### 实操案例 创建项目`javacode2018-pom-import`，具体过程不演示了，坐标信息： ``` <groupId>com.javacode2018</groupId> <artifactId>javacode2018-pom-import</artifactId> <version>1.0-SNAPSHOT</version> ``` 创建完毕之后，如下图：  修改`javacode2018-pom-import/pom.xml`内容，如下： ```xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.javacode2018</groupId> <artifactId>javacode2018-pom-import</artifactId> <version>1.0-SNAPSHOT</version> <dependencyManagement> <dependencies> <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.62</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> </dependencies> </dependencyManagement> </project> ``` > 上面我们在`dependencyManagement`中声明了2个依赖：fastjson和junit。 在`javacode2018-pom-import/pom.xml`中执行`mvn install`将其安装到本地仓库 ```java D:\code\IdeaProjects\javacode2018-pom-import>mvn install [INFO] Scanning for projects... [INFO] [INFO] --------------< com.javacode2018:javacode2018-pom-import >-------------- [INFO] Building javacode2018-pom-import 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-pom-import --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-pom-import --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-pom-import --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-pom-import\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-pom-import --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-pom-import --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-pom-import --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-pom-import\target\javacode2018-pom-import-1.0-SNAPSHOT.jar [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-pom-import --- [INFO] Installing D:\code\IdeaProjects\javacode2018-pom-import\target\javacode2018-pom-import-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pom-import\1.0-SNAPSHOT\javacode2018-pom-import-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-pom-import\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pom-import\1.0-SNAPSHOT\javacode2018-pom-import-1.0-SNAPSHOT.pom [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.692 s [INFO] Finished at: 2019-11-19T17:23:16+08:00 [INFO] ------------------------------------------------------------------------ ``` 现在我们想在`javacode2018-pc/pom.xml`中使用`javacode2018-pom-import/pom.xml`的`dependencyManagement`元素中定义的`fastjson和junit的依赖`，而我们的`javacode2019-pc`已经继承了`javacode-parent`了，maven中只能单继承，所以没法通过继承的方式来实现了，那么我们可以在`javacode2019-pc/pom.xml`中加入下面配置： ```xml <dependencyManagement> <dependencies> <dependency> <groupId>com.javacode2018</groupId> <artifactId>javacode2018-pom-import</artifactId> <version>1.0-SNAPSHOT</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> ``` 此时可以使用fastjson的依赖了，`javacode2018-pc/pom.xml`中`project->dependencies`元素中加入下面配置： ``` <dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> </dependency> ``` 看一下效果：  > 上面的fastjson没有指定版本号，直接可以使用，说明从`javacode2018-pom-import`传递过来了。 可以点击一下上面红圈中的箭头，会跳到本地仓库的`javacode2018-pom-import-1.0-SNAPSHOT.pom`文件，如下：  ## 插件管理(pluginManagement) maven中提供了dependencyManagement来解决继承的问题，同样也提供了解决插件继承问题的`pluginManagement`元素，在父pom中可以在这个元素中声明插件的配置信息，但是子pom.xml中不会引入此插件的配置信息，只有在子pom.xml中使用`plugins->plugin`元素正在引入这些声明的插件的时候，插件才会起效，子插件中只需要写`groupId、artifactId`，其他信息都可以从父构件中传递过来。 ### 实操案例 在`javacode2018-parent/pom.xml`中加入下面配置： ``` <build> <pluginManagement> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-source-plugin</artifactId> <version>3.2.0</version> <executions> <execution> <id>attach-source</id> <phase>verify</phase> <goals> <goal>jar-no-fork</goal> </goals> </execution> </executions> </plugin> </plugins> </pluginManagement> </build> ``` > maven-source-plugin这个插件在上一章有介绍过，源码打包的。 > > 上面是将插件`maven-source-plugin`的`jar-no-fork`目标绑定在`default`生命周期的`verify`阶段，`verify`阶段会在default生命周期的`install`周期前面执行。 > > 下面我们看效果。 在javacode2018-pc/pom.xml所在目录运行下面命令 ``` D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc>mvn clean install [INFO] Scanning for projects... [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------- [INFO] Building javacode2018-pc 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode2018-pc --- [INFO] Deleting D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-pc --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-pc --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-pc --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.pom [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.254 s [INFO] Finished at: 2019-11-19T16:24:39+08:00 [INFO] ------------------------------------------------------------------------ ``` > mvn clean install 会清理代码，然后将打包构件，将构建安装到本地仓库，从输入中可以看到`javacode2018-pc-1.0-SNAPSHOT.jar`被安装到本地仓库了。 > > 但是没有看到打包源码的插件的运行，说明了`javacode2018-pc`没有从父pom.xml中继承插件的配置信息，所以插件配置没有起效，现在我们要让插件起效，继续看： 在javacode2018-pc/pom.xml中加入下面配置： ```xml <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-source-plugin</artifactId> </plugin> </plugins> </build> ``` 截图看效果：  又一个线上的箭头，说明这个是从父pom.xml中传递过来了，大家仔细看一下上面的配置，插件只写了`groupId、artifactId`，其他信息都没有写，其他信息都可以从父pom.xml中传递过来，下面我们看一下插件是否起效了，运行下面命令，见证奇迹： ```java D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc>mvn clean install [INFO] Scanning for projects... [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------- [INFO] Building javacode2018-pc 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode2018-pc --- [INFO] Deleting D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-pc --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-pc --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] [INFO] --- maven-source-plugin:3.2.0:jar-no-fork (attach-source) @ javacode2018-pc --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT-sources.jar [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-pc --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.pom [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT-sources.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT-sources.jar [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.477 s [INFO] Finished at: 2019-11-19T16:28:18+08:00 [INFO] ------------------------------------------------------------------------ ``` > 注意上面的输出中有`attach-source`，这个就是上面我们插件任务的id，输出中还有`javacode2018-pc-1.0-SNAPSHOT-sources.jar`信息，说明源码也是打包成功了，最后也是上传到了本地仓库了。 上面演示了只用在子pom.xml中写上插件的`groupId、artifactId`就可以了，其他信息会从父pom.xml中插件的定义中传递过来，而子pom.xml中也可以自定义插件的这些配置，修改`javacode2018-pc/pom.xml`配置，如下： ``` <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-source-plugin</artifactId> <executions> <execution> <id>attach-source</id> <goals> <goal>help</goal> </goals> </execution> </executions> </plugin> </plugins> </build> ``` 再看一下效果： ```java D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc>mvn clean install [INFO] Scanning for projects... [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------- [INFO] Building javacode2018-pc 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ javacode2018-pc --- [INFO] Deleting D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-pc --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-pc --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] [INFO] --- maven-source-plugin:3.2.0:help (attach-source) @ javacode2018-pc --- [INFO] Apache Maven Source Plugin 3.2.0 The Maven Source Plugin creates a JAR archive of the source files of the current project. This plugin has 7 goals: source:aggregate Aggregate sources for all modules in an aggregator project. source:generated-test-jar This plugin bundles all the test sources into a jar archive. source:help Display help information on maven-source-plugin. Call mvn source:help -Ddetail=true -Dgoal=<goal-name> to display parameter details. source:jar This plugin bundles all the sources into a jar archive. source:jar-no-fork This goal bundles all the sources into a jar archive. This goal functions the same as the jar goal but does not fork the build and is suitable for attaching to the build lifecycle. source:test-jar This plugin bundles all the test sources into a jar archive. source:test-jar-no-fork This goal bundles all the test sources into a jar archive. This goal functions the same as the test-jar goal but does not fork the build, and is suitable for attaching to the build lifecycle. [INFO] [INFO] --- maven-source-plugin:3.2.0:jar-no-fork (attach-source) @ javacode2018-pc --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT-sources.jar [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-pc --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.pom [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT-sources.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT-sources.jar [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 2.752 s [INFO] Finished at: 2019-11-19T16:41:21+08:00 [INFO] ------------------------------------------------------------------------ ``` 输出中有下面2行： ``` [INFO] --- maven-source-plugin:3.2.0:help (attach-source) @ javacode2018-pc --- [INFO] --- maven-source-plugin:3.2.0:jar-no-fork (attach-source) @ javacode2018-pc --- ``` 说明`maven-source-plugin`插件执行了2个目标：`help`和`jar-no-fork`。此时父子pom.xml中插件配置信息合并了，所以出现了2个目标。具体最终`javacode2018-pc/pom.xml`中的内容是什么样的，可以通过下面这个命令看到： ```java mvn help:effective-pom ``` 上面这个命令大家最好去看一下效果，当pom.xml中存在复杂的关系的时候，可以通过这个命令解析得到这个构件最终pom.xml的内容。 ## 聚合与继承的关系 前面已经详解了聚合和继承，想必大家对这块也有了自己的理解。 聚合主要是为了方便多模块快速构建。 而继承主要是为了重用相同的配置。 对于聚合来说，聚合模块是知道被聚合模块的存在的，而被聚合模块是感知不到聚合模块的存在。 对于继承来说，父构件是感知不到子构件的存在，而子构件需要使用`parent`来引用父构件。 两者的共同点是，聚合模块和继承中的父模块的package属性都必须是pom类型的，同时，聚合模块和父模块中的除了pom.xml，一般都是没有什么内容的。 实际使用是，我们经常将聚合和继承一起使用，能同时使用到两者的优点。 下面我们在`javacode2018-parent`中加入聚合的配置： ``` <modules> <module>javacode2018-pc</module> <module>javacode2018-h5</module> <module>javacode2018-api</module> </modules> ``` javacode20180-parent/pom.xml目录运行一下mvn install，看看效果： ``` D:\code\IdeaProjects\javacode2018-parent>mvn install [INFO] Scanning for projects... [INFO] ------------------------------------------------------------------------ [INFO] Reactor Build Order: [INFO] [INFO] javacode2018-parent [pom] [INFO] javacode2018-pc [jar] [INFO] javacode2018-h5 [jar] [INFO] javacode2018-api [jar] [INFO] [INFO] ----------------< com.javacode2018:javacode2018-parent >---------------- [INFO] Building javacode2018-parent 1.0-SNAPSHOT [1/4] [INFO] --------------------------------[ pom ]--------------------------------- [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-parent --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-parent\1.0-SNAPSHOT\javacode2018-parent-1.0-SNAPSHOT.pom [INFO] [INFO] ------------------< com.javacode2018:javacode2018-pc >------------------ [INFO] Building javacode2018-pc 1.0-SNAPSHOT [2/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-pc --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-pc --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-pc --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-pc --- [INFO] [INFO] --- maven-source-plugin:3.2.0:help (attach-source) @ javacode2018-pc --- [INFO] Apache Maven Source Plugin 3.2.0 The Maven Source Plugin creates a JAR archive of the source files of the current project. This plugin has 7 goals: source:aggregate Aggregate sources for all modules in an aggregator project. source:generated-test-jar This plugin bundles all the test sources into a jar archive. source:help Display help information on maven-source-plugin. Call mvn source:help -Ddetail=true -Dgoal=<goal-name> to display parameter details. source:jar This plugin bundles all the sources into a jar archive. source:jar-no-fork This goal bundles all the sources into a jar archive. This goal functions the same as the jar goal but does not fork the build and is suitable for attaching to the build lifecycle. source:test-jar This plugin bundles all the test sources into a jar archive. source:test-jar-no-fork This goal bundles all the test sources into a jar archive. This goal functions the same as the test-jar goal but does not fork the build, and is suitable for attaching to the build lifecycle. [INFO] [INFO] --- maven-source-plugin:3.2.0:jar-no-fork (attach-source) @ javacode2018-pc --- [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-pc --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT.pom [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-pc\target\javacode2018-pc-1.0-SNAPSHOT-sources.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-pc\1.0-SNAPSHOT\javacode2018-pc-1.0-SNAPSHOT-sources.jar [INFO] [INFO] ------------------< com.javacode2018:javacode2018-h5 >------------------ [INFO] Building javacode2018-h5 1.0-SNAPSHOT [3/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-h5 --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-h5 --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-h5 --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-parent\javacode2018-h5\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-h5 --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-h5 --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-h5 --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-h5\target\javacode2018-h5-1.0-SNAPSHOT.jar [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-h5 --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-h5\target\javacode2018-h5-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-h5\1.0-SNAPSHOT\javacode2018-h5-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-h5\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-h5\1.0-SNAPSHOT\javacode2018-h5-1.0-SNAPSHOT.pom [INFO] [INFO] -----------------< com.javacode2018:javacode2018-api >------------------ [INFO] Building javacode2018-api 1.0-SNAPSHOT [4/4] [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ javacode2018-api --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ javacode2018-api --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ javacode2018-api --- [WARNING] Using platform encoding (GBK actually) to copy filtered resources, i.e. build is platform dependent! [INFO] skip non existing resourceDirectory D:\code\IdeaProjects\javacode2018-parent\javacode2018-api\src\test\resources [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ javacode2018-api --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ javacode2018-api --- [INFO] No tests to run. [INFO] [INFO] --- maven-jar-plugin:2.4:jar (default-jar) @ javacode2018-api --- [INFO] Building jar: D:\code\IdeaProjects\javacode2018-parent\javacode2018-api\target\javacode2018-api-1.0-SNAPSHOT.jar [INFO] [INFO] --- maven-install-plugin:2.4:install (default-install) @ javacode2018-api --- [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-api\target\javacode2018-api-1.0-SNAPSHOT.jar to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-api\1.0-SNAPSHOT\javacode2018-api-1.0-SNAPSHOT.jar [INFO] Installing D:\code\IdeaProjects\javacode2018-parent\javacode2018-api\pom.xml to C:\Users\Think\.m2\repository\com\javacode2018\javacode2018-api\1.0-SNAPSHOT\javacode2018-api-1.0-SNAPSHOT.pom [INFO] ------------------------------------------------------------------------ [INFO] Reactor Summary for javacode2018-parent 1.0-SNAPSHOT: [INFO] [INFO] javacode2018-parent ................................ SUCCESS [ 0.416 s] [INFO] javacode2018-pc .................................... SUCCESS [ 2.654 s] [INFO] javacode2018-h5 .................................... SUCCESS [ 0.262 s] [INFO] javacode2018-api ................................... SUCCESS [ 0.225 s] [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3.827 s [INFO] Finished at: 2019-11-19T17:51:42+08:00 [INFO] ------------------------------------------------------------------------ ``` ## 上篇文章中留下的2个问题 ### 问题1 **下面这个配置是干什么的？给哪个插件使用的？** ```xml <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> ``` 编译代码的时候，涉及到资源文件和测试资源文件的拷贝，拷贝文件的时候涉及到文件的编码，这个是设置文件的编码为`UTF-8`格式的。 我们在上篇文章的`maven-chat06`项目的目录中执行`mvn compile`命令，效果如下： ```java D:\code\IdeaProjects\maven-chat06>mvn compile [INFO] Scanning for projects... [INFO] [INFO] -------------------< com.javacode2018:maven-chat06 >-------------------- [INFO] Building maven-chat06 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ maven-chat06 --- [INFO] Using 'UTF-8' encoding to copy filtered resources. [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ maven-chat06 --- [INFO] Nothing to compile - all classes are up to date [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.179 s [INFO] Finished at: 2019-11-19T17:57:27+08:00 [INFO] ------------------------------------------------------------------------ ``` 可以看到上面有这样的输出： ```java [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ maven-chat06 --- [INFO] Using 'UTF-8' encoding to copy filtered resources. ``` 从上面可以看出`maven-resources-plugin`插件的`resources`目标中会使用这个编码的配置，我们来看一下这个目标具体参数配置，我们截取了部分输出，如下： ```java D:\code\IdeaProjects\maven-chat06>mvn help:describe -Dplugin=resources -Dgoal=resources -Ddetail [INFO] Scanning for projects... [INFO] [INFO] -------------------< com.javacode2018:maven-chat06 >-------------------- [INFO] Building maven-chat06 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-help-plugin:3.2.0:describe (default-cli) @ maven-chat06 --- [INFO] Mojo: 'resources:resources' resources:resources Description: Copy resources for the main source code to the main output directory. Always uses the project.build.resources element to specify the resources to copy. Implementation: org.apache.maven.plugin.resources.ResourcesMojo Language: java Bound to phase: process-resources Available parameters: delimiters Set of delimiters for expressions to filter within the resources. These delimiters are specified in the form 'beginToken*endToken'. If no '*' is given, the delimiter is assumed to be the same for start and end. So, the default filtering delimiters might be specified as: <delimiters> <delimiter>${*}</delimiter> <delimiter>@</delimiter> </delimiters> Since the '@' delimiter is the same on both ends, we don't need to specify '@*@' (though we can). encoding (Default: ${project.build.sourceEncoding}) User property: encoding The character encoding scheme to be applied when filtering resources. ``` 注意上面输出中最后的一部分，如下： ```java encoding (Default: ${project.build.sourceEncoding}) User property: encoding The character encoding scheme to be applied when filtering resources. ``` encoding这个参数用来指定编码的，默认值是`${project.build.sourceEncoding}`，也可以通过`encoding`用户属性来设置。 所以这个设置编码的还有下面3种写法，共四种： ``` pom.xml中2种： <encoding>UTF-8</encoding> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> mvn命令中2种： mvn compile -Dencoding=UTF-8 mvn compile -Dproject.build.sourceEncoding=UTF-8 ``` ### 问题2 **mvn test运行测试用例的时候，测试用例类名的写法默认是有规则的，这些规则有人知道么？从哪里可以看到这些规则？如何自定义？** 我们在上一篇中的`maven-chat06`项目中执行`mvn test`，看看效果： ```java D:\code\IdeaProjects\maven-chat06>mvn test [INFO] Scanning for projects... [INFO] [INFO] -------------------< com.javacode2018:maven-chat06 >-------------------- [INFO] Building maven-chat06 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ maven-chat06 --- [INFO] Using 'UTF-8' encoding to copy filtered resources. [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ maven-chat06 --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ maven-chat06 --- [INFO] Using 'UTF-8' encoding to copy filtered resources. [INFO] Copying 0 resource [INFO] [INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ maven-chat06 --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ maven-chat06 --- [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 1.411 s [INFO] Finished at: 2019-11-19T18:07:52+08:00 [INFO] ------------------------------------------------------------------------ ``` 可以看到下面这行： ```java [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ maven-chat06 --- ``` 表示运行测试使用的是插件`maven-surefire-plugin`的`test`目标。 我们看看这个目标详细参数，只列出部分信息，如下： ```java D:\code\IdeaProjects\maven-chat06>mvn help:describe -Dplugin=surefire -Dgoal=test -Ddetail [INFO] Scanning for projects... [INFO] [INFO] -------------------< com.javacode2018:maven-chat06 >-------------------- [INFO] Building maven-chat06 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-help-plugin:3.2.0:describe (default-cli) @ maven-chat06 --- [INFO] Mojo: 'surefire:test' surefire:test Description: Run tests using Surefire. Implementation: org.apache.maven.plugin.surefire.SurefirePlugin Language: java Bound to phase: test Available parameters: includes A list of <include> elements specifying the tests (by pattern) that should be included in testing. When not specified and when the test parameter is not specified, the default includes will be <includes> <include>**/IT*.java</include> <include>**/*IT.java</include> <include>**/*ITCase.java</include> </includes> Each include item may also contain a comma-separated sublist of items, which will be treated as multiple <include> entries. This parameter is ignored if the TestNG suiteXmlFiles parameter is specified. [INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 4.458 s [INFO] Finished at: 2019-11-19T18:10:09+08:00 [INFO] ------------------------------------------------------------------------ ``` 可以看到上面有个`includes`参数，可以用来配置需要运行的测试用例，可以配置通配符的方式。 上面还有一段信息： ```java Implementation: org.apache.maven.plugin.surefire.SurefirePlugin ``` 上面这部分列出了这个目标的具体实现类是`SurefirePlugin`。 那么我们可以到本地仓库中看一下这个构件的源码，构件的坐标是： ```xml <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <version>2.12.4</version> ``` 打开`org.apache.maven.plugin.surefire.SurefirePlugin`的源码，会找到下面代码： ```java protected String[] getDefaultIncludes() { return new String[]{ "**/Test*.java", "**/*Test.java", "**/*TestCase.java" }; } ``` 这部分代码就是我们测试用例默认需要满足的格式，你创建的测试用例默认情况下必须满足上面这3种格式，否则，测试用例不会被`mvn test`执行。 ## 总结 1. 需要掌握聚合的使用 2. 掌握继承的使用 3. 掌握单继承问题解决方案 4. 掌握依赖管理和插件管理的使用 **还是那句话，建议大家下去了多练练，都操作一遍，加深理解！** <a style="display:none" target="_blank" href="https://mp.weixin.qq.com/s/_S1DD2JADnXvpexxaBwLLg" style="color:red; font-size:20px; font-weight:bold">继续收门徒，亲手带，月薪 4W 以下的可以来找我</a> ## 最新资料 1. <a href="https://mp.weixin.qq.com/s?__biz=MzkzOTI3Nzc0Mg==&mid=2247484964&idx=2&sn=c81bce2f26015ee0f9632ddc6c67df03&scene=21#wechat_redirect" target="_blank">尚硅谷 Java 学科全套教程（总 207.77GB）</a> 2. <a href="https://mp.weixin.qq.com/s?__biz=MzkwOTAyMTY2NA==&mid=2247484192&idx=1&sn=505f2faaa4cc911f553850667749bcbb&scene=21#wechat_redirect" target="_blank">2021 最新版 Java 微服务学习线路图 + 视频</a> 3. <a href="https://mp.weixin.qq.com/s?__biz=MzkwOTAyMTY2NA==&mid=2247484573&idx=1&sn=7f3d83892186c16c57bc0b99f03f1ffd&scene=21#wechat_redirect" target="_blank">阿里技术大佬整理的《Spring 学习笔记.pdf》</a> 4. <a href="https://mp.weixin.qq.com/s?__biz=MzkwOTAyMTY2NA==&mid=2247484544&idx=2&sn=c1dfe907cfaa5b9ae8e66fc247ccbe84&scene=21#wechat_redirect" target="_blank">阿里大佬的《MySQL 学习笔记高清.pdf》</a> 5. <a href="https://mp.weixin.qq.com/s?__biz=MzkwOTAyMTY2NA==&mid=2247485167&idx=1&sn=48d75c8e93e748235a3547f34921dfb7&scene=21#wechat_redirect" target="_blank">2021 版 java 高并发常见面试题汇总.pdf</a> 6. <a href="https://mp.weixin.qq.com/s?__biz=MzkwOTAyMTY2NA==&mid=2247485664&idx=1&sn=435f9f515a8f881642820d7790ad20ce&scene=21#wechat_redirect" target="_blank">Idea 快捷键大全.pdf</a> 
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