使用maven-shard解决依赖/类冲突

1. Why?

通过 maven-shade-plugin 生成一个 fat jar，它包含所有的依赖 jar 包。

注意jar包版本冲突可以通过mvn dependency:tree来分析，但是不同jar包类冲突的话不能简单的通过版本来解决。

2. Usage

2.1 配置 maven-shade-plugin

maven-shade-plugin 将 goal shade:shade 绑定到 phase package 上。

 <build>
     <plugins>
         <plugin>
             <groupId>org.apache.maven.plugins</groupId>
             <artifactId>maven-shade-plugin</artifactId>
             <version>2.4.3</version>
             <configuration>
                 <!-- put your configurations here -->
             </configuration>
             <executions>
                 <execution>
                     <phase>package</phase>
                     <goals>
                         <goal>shade</goal>
                     </goals>
                 </execution>
             </executions>
         </plugin>
     </plugins>
 </build>

2.2 执行命令

mvn clean package

会在 target 文件生成一个两个jar包，其中以 -shaded.jar 为后缀的 jar 包，就是我们要的jar包

2.3 Examples

将该工程依赖的部分 Jar 包 include/exclude 掉。

<build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.4.3</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <artifactSet>
                <excludes>
                  <exclude>classworlds:classworlds</exclude>
                  <exclude>junit:junit</exclude>
                  <exclude>jmock:*</exclude>
                  <exclude>*:xml-apis</exclude>
                  <exclude>org.apache.maven:lib:tests</exclude>
                  <exclude>log4j:log4j:jar:</exclude>
                </excludes>
              </artifactSet>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
</build>

将依赖的某个 Jar 包内部的类或者资源 include/exclude 掉。

<build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.4.3</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <filters>
                <filter>
                  <artifact>junit:junit</artifact>
                  <includes>
                    <include>junit/framework/**</include>
                    <include>org/junit/**</include>
                  </includes>
                  <excludes>
                    <exclude>org/junit/experimental/**</exclude>
                    <exclude>org/junit/runners/**</exclude>
                  </excludes>
                </filter>
                <filter>
                  <artifact>*:*</artifact>
                  <excludes>
                    <exclude>META-INF/*.SF</exclude>
                    <exclude>META-INF/*.DSA</exclude>
                    <exclude>META-INF/*.RSA</exclude>
                  </excludes>
                </filter>
              </filters>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
<\build>

2.4 Relocating Classes

Java 工程经常会遇到第三方 Jar 包冲突，使用 maven shade plugin 解决 jar 或类的多版本冲突。 maven-shade-plugin 在打包时，可以将项目中依赖的 jar 包中的一些类文件打包到项目构建生成的 jar 包中，在打包的时候把类重命名。下面的配置将 org.codehaus.plexus.util jar 包重命名为 org.shaded.plexus.util。

<build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-shade-plugin</artifactId>
        <version>2.4.3</version>
        <executions>
          <execution>
            <phase>package</phase>
            <goals>
              <goal>shade</goal>
            </goals>
            <configuration>
              <relocations>
                <relocation>
                  <pattern>org.codehaus.plexus.util</pattern>
                  <shadedPattern>org.shaded.plexus.util</shadedPattern>
                  <excludes>
                    <exclude>org.codehaus.plexus.util.xml.Xpp3Dom</exclude>
                    <exclude>org.codehaus.plexus.util.xml.pull.*</exclude>
                  </excludes>
                </relocation>
              </relocations>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

参考链接：
blog.csdn.net/u011250186/…

blog.csdn.net/kezhong_wxl…

例子：

<?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.example</groupId>
    <artifactId>hadoop-aliyun-sharded</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-aliyun</artifactId>
            <version>2.7.2-rc5</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <!--编译plugin-->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.1.1</version>
                <configuration>
                    <artifactSet>
                        <excludes>
                            <exclude>org.apache.commons:*</exclude>
                            <exclude>org.codehaus:*</exclude>
                            <exclude>org.jdom:*</exclude>
                        </excludes>
                    </artifactSet>
                    <filters>
                        <filter>
                            <artifact>*:*</artifact>
                            <excludes>
                                <exclude>META-INF/*.SF</exclude>
                                <exclude>META-INF/*.DSA</exclude>
                                <exclude>META-INF/*.RSA</exclude>
                            </excludes>
                        </filter>
                    </filters>

                    <relocations>
                        <relocation>
                            <pattern>org.apache.commons</pattern>
                            <shadedPattern>shade.org.apache.commons</shadedPattern>
                        </relocation>
                        <relocation>
                            <pattern>org.codehaus</pattern>
                            <shadedPattern>shade.org.codehaus</shadedPattern>
                        </relocation>
                        <relocation>
                            <pattern>org.jdom</pattern>
                            <shadedPattern>shade.org.jdom</shadedPattern>
                        </relocation>
                    </relocations>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <shadedArtifactAttached>true</shadedArtifactAttached>
                            <shadedClassifierName></shadedClassifierName>
                        </configuration>

                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>