Maven打包插件之——maven-jar-plugin、maven-assembly-plugin、maven-shade-plugin

1. 打包插件的介绍

      打包插件是把class文件，配置文件打包成一个jar(war或者其他格式)的包。而且可执行jar包中包含或者不包含相应的依赖包包，当不包含相应的依赖包时，我们需要建立lib目录，且jar和lib目录在同级别目录。

2. 常见的打包插件

      2.1 maven-jar-plugin

            可执行jar包与依赖包是分开的，需要建立lib目录来存放所需的依赖包，且jar包与lib目录在同级别目录中，相应的pom配置如下：

             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-jar-plugin</artifactId>
                 <version>2.6</version>
                 <configuration>
                    <archive>
                         <manifest>
                             <addClasspath>true</addClasspath>
                             <classpathPrefix>lib/</classpathPrefix>
                            <mainClass>com.xxx.xxxService</mainClass>
                       </manifest>
                    </archive>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.10</version>
                <executions>
                    <execution>
                        <id>copy-dependencies</id>
                        <phase>package</phase>
                        <goals>
                            <goal>copy-dependencies</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>${project.build.directory}/lib</outputDirectory>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

      2.2 maven-assembly-plugin

            该插件会将所有的依赖包放入可执行jar包，但是该插件会缺失spring的xds文件，导致jar包无法运行，而且当同级别目录下还有其他可执行文件依赖可能会产生冲突，相应的pom配置如下：

             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <configuration>
                     <descriptorRefs>
                         <descriptorRef>jar-with-dependencies</descriptorRef>
                     </descriptorRefs>
                     <archive>
                         <manifest>
                             <mainClass>com.xxx.xxxService</mainClass>
                        </manifest>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <id>make-assembly</id>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

      2.3 maven-shade-plugin

            该插件将所有的依赖包放入可执行的jar包中，当同级别目录中有其他的可执行jar包时，依赖可能会产生冲突，且运行jar包时，有时候会出现类似SF，DSA，RSA文件冲突的提示，选哟派相互META-INF目录下的文件，相应pom位置如下：

　　　　<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>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.handlers</resource>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.schemas</resource>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.tooling</resource>
                                </transformer>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>com.xxx.xxxInvoke</mainClass>
                                </transformer>
                            </transformers>
                            <minimizeJar>true</minimizeJar>
                            <shadedArtifactAttached>true</shadedArtifactAttached>
                        </configuration>
                    </execution>
                </executions>
            </plugin>