（III）Maven - clean compile

2019年6月29日 308次阅读来源: miku设定

在进行完基本的POM配置之后，我们来举个’小李子’吧

package com.play.myMaven;

/**
 * Hello Maven
 *
 * @author Songyanyan
 */
public class HelloWorld {
  public String sayHello(){
    return "Hello World";
  }

  public static void main(String[] args) {
   System.out.println(new HelloWorld().sayHello());
  }
}

虽然是个简单的‘李子’，我们仍需要注意两点

在绝大多数情况下，应该把项目主代码放到src/main/java/目录下（遵循年Maven的约定），Maven会自动搜寻该目录找到项目主代码
一般来说，项目中Java类的包都应该基于项目的groupId和artifactId，这样更加清晰，同时也方便搜索构件/Java类

清理和编译

开始编译咯！
在项目根目录下运行命令mvn clean compile
emmmm，遗憾的是并没有那么顺利的像书中那样一次通过，发生了什么呢？（没有出现这个问题的小伙伴可以直接跳过这一部分）

C:\Subversion\MavenPrj\helloMaven>mvn clean complie
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building parent 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.265 s
[INFO] Finished at: 2018-06-05T15:21:33+08:00
[INFO] Final Memory: 6M/123M
[INFO] ------------------------------------------------------------------------
[ERROR] Unknown lifecycle phase "complie". You must specify a valid lifecycle phase or a goal in the format <plugin-prefix>:<goal> or <plugin-group-i
d>:<plugin-artifact-id>[:<plugin-version>]:<goal>. Available lifecycle phases are: validate, initialize, generate-sources, process-sources, generate-
resources, process-resources, compile, process-classes, generate-test-sources, process-test-sources, generate-test-resources, process-test-resources,
  test-compile, process-test-classes, test, prepare-package, package, pre-integration-test, integration-test, post-integration-test, verify, install,
deploy, pre-clean, clean, post-clean, pre-site, site, post-site, site-deploy. -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/LifecyclePhaseNotFoundException

第一个问题: 是mvn clean compile !!! 不是complie
修正后，再次执行 mvn clean compile:

C:\Subversion\MavenPrj\helloMaven>mvn clean complie
java.lang.NoClassDefFoundError:     Lorg/sonatype/plexus/build/incremental/BuildContext;
    at java.lang.Class.getDeclaredFields0(Native Method)
    at java.lang.Class.privateGetDeclaredFields(Class.java:2583)
    at java.lang.Class.getDeclaredFields(Class.java:1916)
...
Caused by: java.lang.ClassNotFoundException: org.sonatype.plexus.build.incremental.BuildContext
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass(ClassRealm.java:271)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:247)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
...
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.292 s
[INFO] Finished at: 2018-06-05T16:20:13+08:00
[INFO] Final Memory: 7M/123M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-resources-plugin:2.6:resources (default-resources) on project hello-maven: Execution de
fault-resources of goal org.apache.maven.plugins:maven-resources-plugin:2.6:resources failed: A required class was missing while executing org.apache
.maven.plugins:maven-resources-plugin:2.6:resources: Lorg/sonatype/plexus/build/incremental/BuildContext;

又一次的FAILURE，无奈，那就用Maven Projects默认的Lifecycle中compile直接执行，和上面的报错一致，百度一圈也没找到合适方案，嗯，那就拆开检查！
执行mvn clean：

C:\Subversion\MavenPrj\helloMaven>mvn clean
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building parent 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:2.5:clean (default-clean) @ hello-maven ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.175 s
[INFO] Finished at: 2018-06-05T16:28:02+08:00
[INFO] Final Memory: 6M/123M
[INFO] ------------------------------------------------------------------------

这次构建成功，那看来就是complie的问题了，看了下plugins中的版本，会不会是版本问题呢？于是看了下最新的Maven plugins信息，更新了一些默认构建插件：

<build><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
    <plugins>
        <plugin>
            <artifactId>maven-clean-plugin</artifactId>
            <version>3.0.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
            <artifactId>maven-resources-plugin</artifactId>
            <version>3.0.2</version>
        </plugin>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.7.0</version>
        </plugin>
        <plugin>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>2.20.1</version>
        </plugin>
        <plugin>
            <artifactId>maven-jar-plugin</artifactId>
            <version>3.0.2</version>
        </plugin>
        <plugin>
            <artifactId>maven-install-plugin</artifactId>
            <version>2.5.2</version>
        </plugin>
        <plugin>
            <artifactId>maven-deploy-plugin</artifactId>
            <version>2.8.2</version>
        </plugin>
    </plugins>
</build>

《（III）Maven - clean compile》 Maven3.3.9的默认构建插件版本信息.jpg

《（III）Maven - clean compile》加载了新插件的构建版本信息.png

执行mvn clean compile:

C:\Subversion\MavenPrj\helloMaven>mvn clean compile
[INFO] Scanning for projects...
[INFO]

[INFO] ------------------------------------------------------------------------
[INFO] Building parent 1.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-clean-plugin:3.0.0:clean (default-clean) @ hello-maven ---
[INFO] Deleting C:\Subversion\MavenPrj\helloMaven\target
[INFO]
[INFO] --- maven-resources-plugin:3.0.2:resources (default-resources) @ hello-maven ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory C:\Subversion\MavenPrj\helloMaven\src\main\resources
[INFO]
[INFO] --- maven-compiler-plugin:3.7.0:compile (default-compile) @hello-maven ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to C:\Subversion\MavenPrj\helloMaven\target\classes
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.086 s
[INFO] Finished at: 2018-06-05T16:52:18+08:00
[INFO] Final Memory: 14M/207M
[INFO] ------------------------------------------------------------------------

构建成功！
分析一下log，使用到的构建都会有对应的版本信息输出：

Scanning for projects :正在扫描
Building parent 1.0-SNAPSHOT :正在构建parent 1.0-SNAPSHOT
clean :告诉Maven清理输出目录C:\Subversion\MavenPrj\helloMaven\target
Using ‘UTF-8’ encoding to copy filtered resources. :使用“UTF-8”编码复制过滤资源这是在<properties>中添加了
```
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
```

可以避免出现警告[WARNING] Using platform encoding (UTF-8 actually) to copy filter

compile :告诉Maven编译项目主代码

执行顺序：clean:clean任务，删除target/目录（默认情况下，Maven构建的所有输出都在target/目录中），接着执行resources:resources任务（这里未定义项目资源，暂且略过），最后执行compiler:compile任务将项目主代码编译至target/classes目录

上面所提到的clean:clean，resources:resources，compiler:compile
分别对应各插件的不同goal

以上就完成了项目的清理和编译任务，接下来写一些单元测试代码并让Maven执行自动化测试

自动化测试

主代码和测试代码分别位于独立的目录中。Maven项目默认的主代码目录：src/main/java ，默认的测试代码目录是src/test/java

先为项目添加一个JUnit依赖

<dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
</dependencies>

有了groupId：junit，artifactId：junit，version：4.11这三个值的声明，就可以确认这个JUnit的坐标，Maven可以访问中央仓库并自动下载junit-4.11.jar（而在Maven之前我们需要自行去JUnit官网下载分发包）
scope为依赖范围，值为test表示该依赖只对测试有效。也就是，测试代码中import JUnit是OK的，但是在主代码中import JUnit会有编译错误。不声明默认值为compile，表示该依赖对主代码和测试代码都有效。
我们来测试一下Hello World类的sayHello()方法吧，对应主代码目录生成测试目录结构，如图：

《（III）Maven - clean compile》主代码目录结构和测试代码目录结构.png

package com.play.myMaven;
import org.junit.Test;
import static org.junit.Assert.assertEquals;

/**
 * HellMavenTest
 *
 * @author Songyanyan
 */
public class HelloWorldTest {
  @Test
  public void testSayHello() {
    HelloWorld helloWorld = new HelloWorld();
    String result = helloWorld.sayHello();
    assertEquals("Hello Maven", result);
  }
}

典型的单元测试有三个步骤：

测试类及测试数据
测试的信访维

检查结果
调用Maven执行测试。运行mvn clean test
正确结果如下：

  C:\Subversion\MavenPrj\helloMaven>mvn clean test
  [INFO] Scanning for projects...
  [INFO]
  [INFO] ------------------------------------------------------------------------
  [INFO] Building parent 1.0-SNAPSHOT
  [INFO] ------------------------------------------------------------------------
  [INFO]
  [INFO] --- maven-clean-plugin:3.0.0:clean (default-clean) @ hello-maven ---
  [INFO] Deleting C:\Subversion\MavenPrj\helloMaven\target
  [INFO]
  [INFO] --- maven-resources-plugin:3.0.2:resources (default-resources) @ hello-maven ---
  [INFO] Using 'UTF-8' encoding to copy filtered resources.
  [INFO] skip non existing resourceDirectory C:\Subversion\MavenPrj\helloMaven\src\main\resources
  [INFO]
  [INFO] --- maven-compiler-plugin:3.7.0:compile (default-compile) @ hello-maven ---
  [INFO] Changes detected - recompiling the module!
  [INFO] Compiling 1 source file to C:\Subversion\MavenPrj\helloMaven\target\classes
  [INFO]
  [INFO] --- maven-resources-plugin:3.0.2:testResources (default-testResources) @ hello-maven ---
  [INFO] Using 'UTF-8' encoding to copy filtered resources.
  [INFO] skip non existing resourceDirectory C:\Subversion\MavenPrj\helloMaven\src\test\resources
  [INFO]
  [INFO] --- maven-compiler-plugin:3.7.0:testCompile (default-testCompile) @ hello-maven ---
  [INFO] Changes detected - recompiling the module!
  [INFO] Compiling 1 source file to C:\Subversion\MavenPrj\helloMaven\target\test-classes
  [INFO]
  [INFO] --- maven-surefire-plugin:2.20.1:test (default-test) @ hello-maven ---
  [INFO]
  [INFO] -------------------------------------------------------
  [INFO]  T E S T S
  [INFO] -------------------------------------------------------
  [INFO] Running com.play.myMaven.HelloWorldTest
  [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.02 s - in com.play.myMaven.HelloWorldTest
  [INFO]
  [INFO] Results:
  [INFO]
  [INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
  [INFO]
  [INFO] ------------------------------------------------------------------------
  [INFO] BUILD SUCCESS
  [INFO] ------------------------------------------------------------------------
  [INFO] Total time: 1.969 s
  [INFO] Finished at: 2018-06-05T19:52:48+08:00
  [INFO] Final Memory: 16M/167M
  [INFO] ------------------------------------------------------------------------

可以看到Maven执行测试test之前，会先进行

clean:clean
resources:resources
compiler:compile
resources:testResources
compiler:testCompile
项目主资源处理、主代码编译、测试资源处理、测试代码编译等操作，这是Maven生命周期的一个特性。
通过编译的测试代码会在target/test-classes生成二进制文件(Compiling 1 source file to C:\Subversion\MavenPrj\helloMaven\target\test-classes)，
然后紧接着surefire:test任务运行测试（surfire是maven中负责测试的插件），运行测试用例，并给出测试报告，显然这个是测试通过的例子，结果Results:运行1条，失败0条，编译错误0条，跳过0条

我们来看一下测试失败的情况：

    C:\Subversion\MavenPrj\helloMaven>mvn clean test
    ...
    [INFO] -------------------------------------------------------
    [INFO]  T E S T S
    [INFO] -------------------------------------------------------
    [INFO] Running com.play.myMaven.HelloWorldTest
    [ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.025 s <<< FAILURE! - in com.play.myMaven.HelloWorldTest
    [ERROR] testSayHello(com.play.myMaven.HelloWorldTest)  Time elapsed: 0.006 s  <<< FAILURE!
    org.junit.ComparisonFailure: expected:<Hello [Maven]> but was:<Hello [World]>
            at com.play.myMaven.HelloWorldTest.testSayHello(HelloWorldTest.java:22)
    [INFO]
    [INFO] Results:
    [INFO]
    [ERROR] Failures:
    [ERROR]   HelloWorldTest.testSayHello:22 expected:<Hello [Maven]> but was:<Hello [World]>
    [INFO]
    [ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0
    [INFO]
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD FAILURE
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 2.202 s
    [INFO] Finished at: 2018-06-05T21:18:19+08:00
    [INFO] Final Memory: 16M/163M
    [INFO] ------------------------------------------------------------------------
    [ERROR] Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.20.1:test (default-test) on project hello-maven: There are test failures.
    [ERROR]
    [ERROR] Please refer to C:\Subversion\MavenPrj\helloMaven\target\surefire-reports for the individual test results.
    [ERROR] Please refer to dump files (if any exist) [date]-jvmRun[N].dump, [date].dumpstream and [date]-jvmRun[N].dumpstream.
    [ERROR] -> [Help 1]
    [ERROR]
    [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
    [ERROR] Re-run Maven using the -X switch to enable full debug logging.
    [ERROR]
    [ERROR] For more information about the errors and possible solutions, please read the following articles:
    [ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

…部分都是一样的不再赘述

FAILURE! – in com.play.myMaven.HelloWorldTest
在HelloWorldTest类中出现失败

org.junit.ComparisonFailure: expected:<Hello [Maven]> but was:<Hello [World]> at com.play.myMaven.HelloWorldTest.testSayHello(HelloWorldTest.java:22)
在HelloWorldTest类中22行，期望值为<Hello [Maven]>，但是原类值为<Hello [World]>，通过ｌｏｇ输出可见错误提示也是很明显的
注：《Maven实战》学习笔记

    原文作者：miku设定
    原文地址: https://www.jianshu.com/p/54cb81da33be
    本文转自网络文章，转载此文章仅为分享知识，如有侵权，请联系博主进行删除。