廖雪峯Java12maven基礎-2maven進階-1使用插件

1.maven的Lifecycle，Phase和Goal：

• 使用maven構建項目就是執行Lifecycle
• 執行Lifecycle就是按順序執行一系列Phase
• 每執行一個Phase，都會執行該Phase綁定的若干Goal
• Goal是最小任務單元

2.maven經過調用不一樣的插件Plugin來構建項目的。

mvn compile：執行compile這個Phase時，maven自己並不知道如何執行compile。它是經過插件來執行。maven會調用compiler插件執行compile這個Phase。compiler插件會執行和compile關聯的compiler:compile這個Goal來完成編譯。

3.maven經常使用的標準插件

插件名稱	對應執行的Phase
clean	clea
compiler	compile
surefire	test
jar	package

經常使用插件：

• maven-shade-plugin：打包全部依賴包並生成可執行jar
• cobertura-maven-plugin：生成單元測試覆蓋率報告
• findbugs-maven-plugin：對Java源碼進行靜態分析以找出潛在問題

若是標準的插件沒法知足需求，還能夠自定義插件

3.1maven-shade-plugin

例如：想要建立1個可執行的jar包，同時把全部可依賴的jar包都打包到本身最終生成的jar包中。此時咱們須要在pom.xml中聲明自定義的plugin。注意maven自帶的標準插件好比compile是無須聲明的，只有當咱們加入了其餘的插件才須要聲明。
百度搜索maven shade plugin executable jar，進入其官網，查看示例

<project>
  ...
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>3.2.1</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <transformers>
                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                  <mainClass>org.sonatype.haven.HavenCli</mainClass>
                </transformer>
              </transformers>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
  ...
</project>

進入工程，修改pom.xml，在 標籤後新建 ，並將示例中的 之間的內容複製到 之間
pom.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.forme</groupId>
    <artifactId>OneWorld</artifactId>
    <version>1.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>OneWorld</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version><!--JDK1.8-->
        <maven.compiler.source>1.8</maven.compiler.source><!--Java源碼使用1.8格式-->
        <maven.compiler.target>1.8</maven.compiler.target><!--編譯後的class文件採用1.8格式-->
    </properties>

    <dependencies>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-jcl</artifactId>
            <version>2.10.0</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.10.0</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <!--此處須要指定main方法所在class-->
                                    <mainClass>com.forme.App</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>

  </build>
</project>

App.java

package com.forme;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {
        Log log = LogFactory.getLog(App.class);
        log.info("Hello,world!");
    }
}

AppTest.java

package com.forme;

import static org.junit.Assert.assertTrue;

import org.junit.Test;

/**
 * Unit test for simple App.
 */
public class AppTest 
{
    /**
     * Rigorous Test :-)
     */
    @Test
    public void shouldAnswerWithTrue()
    {
        assertTrue( true );
    }
}

目錄結構

命令行打包成功

#切換到工程根目錄，打包
mvn clean package
#進入target目錄，查看jar文件
ls -lh *jar

能夠看到有2個jar包
original-OneWorld-1.1-SNAPSHOT.jar是maven本身的jar插件生成原始的jar包
OneWorld-1.1-SNAPSHOT.jar是由maven-shade-plugin生成的可執行的jar

java -jar OneWorld-1.1-SNAPSHOT.jar

這樣，能夠方便的經過maven-shade-plugin生成可執行的jar

3.2 cobertura maven plugin usage

搜索cobertura maven plugin usage，進入官網

<project>
  <reporting>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>cobertura-maven-plugin</artifactId>
        <version>2.7</version>
        <reportSets>
          <reportSet>
            <reports>
              <report>cobertura</report>
            </reports>
          </reportSet>
        </reportSets>
      </plugin>
    </plugins>
  </reporting>
</project>

3.2.1 初識cobertura

將 ... 之間的內容複製到pom.xml的 ... 標籤中

<?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.forme</groupId>
    <artifactId>OneWorld</artifactId>
    <version>1.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>OneWorld</name>
    <!--FIXME change it to the project's website-->
    <url>http://www.example.com</url>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.version>1.8</java.version><!--JDK1.8-->
        <maven.compiler.source>1.8</maven.compiler.source><!--Java源碼使用1.8格式-->
        <maven.compiler.target>1.8</maven.compiler.target><!--編譯後的class文件採用1.8格式-->
    </properties>

    <dependencies>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-jcl</artifactId>
            <version>2.10.0</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.logging.log4j</groupId>
            <artifactId>log4j-core</artifactId>
            <version>2.10.0</version>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <!--此處須要修改main函數所在類-->
                                    <mainClass>com.forme.App</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>cobertura-maven-plugin</artifactId>
                <version>2.7</version>
            </plugin>
        </plugins>
    </build>
</project>

App.java

package com.forme;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Hello world!
 *
 */
public class App 
{
    public static void main( String[] args )
    {
        Log log = LogFactory.getLog(App.class);
        log.info("Hello,world!");
    }
    //增長一個求和的方法
    int sum(int ... ns){
        int x = 0;
        for(int n:ns){
            x += n;
        }
        return x;
    }
}

AppTest.java

package com.forme;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import org.junit.Test;

/**
 * Unit test for simple App.
 */
public class AppTest 
{
    /**
     * Rigorous Test :-)
     */
    @Test
    public void shouldAnswerWithTrue()
    {
        assertEquals(6,new App().sum(1,2,3));
    }
}

#切換到項目的根目錄
mvn cobertura:cobertura

進入target/site/cobertura目錄下，打開index.html，能夠查看結果

3.2.2 main方法未執行，完善測試覆蓋率

package com.forme;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

import org.junit.Test;

/**
 * Unit test for simple App.
 */
public class AppTest 
{
    /**
     * Rigorous Test :-)
     */
    @Test
    public void shouldAnswerWithTrue()
    {
        App.main(null);
        assertEquals(6,new App().sum(1,2,3));
    }
}

再次執行mvn cobertura:cobertura，測試覆蓋率達到了100%

4總結：

• maven經過自定義插件能夠執行項目構建時須要的額外功能
• 在pom.xml中聲明插件及配置
• 插件會在某個Phase被執行
• 插件的配置和用法需參考插件官方文檔