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  • Maven打包的三种方式

    Maven可以使用mvn package指令对项目进行打包，如果使用Java -jar xxx.jar执行运行jar文件，会出现"no main manifest attribute, in xxx.jar"（没有设置Main-Class）、ClassNotFoundException（找不到依赖包）等错误。

    要想jar包能直接通过java -jar xxx.jar运行，需要满足：

    1、在jar包中的META-INF/MANIFEST.MF中指定Main-Class，这样才能确定程序的入口在哪里；

    2、要能加载到依赖包。

    使用Maven有以下几种方法可以生成能直接运行的jar包，可以根据需要选择一种合适的方法。

    方法一：使用maven-jar-plugin和maven-dependency-plugin插件打包

    在pom.xml中配置：

    1. <build>  
    2.     <plugins>  
    3.   
    4.         <plugin>  
    5.             <groupId>org.apache.maven.plugins</groupId>  
    6.             <artifactId>maven-jar-plugin</artifactId>  
    7.             <version>2.6</version>  
    8.             <configuration>  
    9.                 <archive>  
    10.                     <manifest>  
    11.                         <addClasspath>true</addClasspath>  
    12.                         <classpathPrefix>lib/</classpathPrefix>  
    13.                         <mainClass>com.xxg.Main</mainClass>  
    14.                     </manifest>  
    15.                 </archive>  
    16.             </configuration>  
    17.         </plugin>  
    18.         <plugin>  
    19.             <groupId>org.apache.maven.plugins</groupId>  
    20.             <artifactId>maven-dependency-plugin</artifactId>  
    21.             <version>2.10</version>  
    22.             <executions>  
    23.                 <execution>  
    24.                     <id>copy-dependencies</id>  
    25.                     <phase>package</phase>  
    26.                     <goals>  
    27.                         <goal>copy-dependencies</goal>  
    28.                     </goals>  
    29.                     <configuration>  
    30.                         <outputDirectory>${project.build.directory}/lib</outputDirectory>  
    31.                     </configuration>  
    32.                 </execution>  
    33.             </executions>  
    34.         </plugin>  
    35.   
    36.     </plugins>  
    37. </build>  

    maven-jar-plugin用于生成META-INF/MANIFEST.MF文件的部分内容，<mainClass>com.xxg.Main</mainClass>指定MANIFEST.MF中的Main-Class，<addClasspath>true</addClasspath>会在MANIFEST.MF加上Class-Path项并配置依赖包，<classpathPrefix>lib/</classpathPrefix>指定依赖包所在目录。

    例如下面是一个通过maven-jar-plugin插件生成的MANIFEST.MF文件片段：

    1. Class-Path: lib/commons-logging-1.2.jar lib/commons-io-2.4.jar  
    2. Main-Class: com.xxg.Main  

    只是生成MANIFEST.MF文件还不够，maven-dependency-plugin插件用于将依赖包拷贝到<outputDirectory>${project.build.directory}/lib</outputDirectory>指定的位置，即lib目录下。

    配置完成后，通过mvn package指令打包，会在target目录下生成jar包，并将依赖包拷贝到target/lib目录下，目录结构如下：

    指定了Main-Class，有了依赖包，那么就可以直接通过java -jar xxx.jar运行jar包。

    这种方式生成jar包有个缺点，就是生成的jar包太多不便于管理，下面两种方式只生成一个jar文件，包含项目本身的代码、资源以及所有的依赖包。

    方法二：使用maven-assembly-plugin插件打包

    在pom.xml中配置：

    1. <build>  
    2.     <plugins>  
    3.   
    4.         <plugin>  
    5.             <groupId>org.apache.maven.plugins</groupId>  
    6.             <artifactId>maven-assembly-plugin</artifactId>  
    7.             <version>2.5.5</version>  
    8.             <configuration>  
    9.                 <archive>  
    10.                     <manifest>  
    11.                         <mainClass>com.xxg.Main</mainClass>  
    12.                     </manifest>  
    13.                 </archive>  
    14.                 <descriptorRefs>  
    15.                     <descriptorRef>jar-with-dependencies</descriptorRef>  
    16.                 </descriptorRefs>  
    17.             </configuration>  
    18.         </plugin>  
    19.   
    20.     </plugins>  
    21. </build>  

    打包方式：

    1. mvn package assembly:single  

    打包后会在target目录下生成一个xxx-jar-with-dependencies.jar文件，这个文件不但包含了自己项目中的代码和资源，还包含了所有依赖包的内容。所以可以直接通过java -jar来运行。

    此外还可以直接通过mvn package来打包，无需assembly:single，不过需要加上一些配置：

    1. <build>  
    2.     <plugins>  
    3.   
    4.         <plugin>  
    5.             <groupId>org.apache.maven.plugins</groupId>  
    6.             <artifactId>maven-assembly-plugin</artifactId>  
    7.             <version>2.5.5</version>  
    8.             <configuration>  
    9.                 <archive>  
    10.                     <manifest>  
    11.                         <mainClass>com.xxg.Main</mainClass>  
    12.                     </manifest>  
    13.                 </archive>  
    14.                 <descriptorRefs>  
    15.                     <descriptorRef>jar-with-dependencies</descriptorRef>  
    16.                 </descriptorRefs>  
    17.             </configuration>  
    18.             <executions>  
    19.                 <execution>  
    20.                     <id>make-assembly</id>  
    21.                     <phase>package</phase>  
    22.                     <goals>  
    23.                         <goal>single</goal>  
    24.                     </goals>  
    25.                 </execution>  
    26.             </executions>  
    27.         </plugin>  
    28.   
    29.     </plugins>  
    30. </build>  

    其中<phase>package</phase>、<goal>single</goal>即表示在执行package打包时，执行assembly:single，所以可以直接使用mvn package打包。

    不过，如果项目中用到spring Framework，用这种方式打出来的包运行时会出错，使用下面的方法三可以处理。

    方法三：使用maven-shade-plugin插件打包

    在pom.xml中配置：

    1. <build>  
    2.     <plugins>  
    3.   
    4.         <plugin>  
    5.             <groupId>org.apache.maven.plugins</groupId>  
    6.             <artifactId>maven-shade-plugin</artifactId>  
    7.             <version>2.4.1</version>  
    8.             <executions>  
    9.                 <execution>  
    10.                     <phase>package</phase>  
    11.                     <goals>  
    12.                         <goal>shade</goal>  
    13.                     </goals>  
    14.                     <configuration>  
    15.                         <transformers>  
    16.                             <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">  
    17.                                 <mainClass>com.xxg.Main</mainClass>  
    18.                             </transformer>  
    19.                         </transformers>  
    20.                     </configuration>  
    21.                 </execution>  
    22.             </executions>  
    23.         </plugin>  
    24.   
    25.     </plugins>  
    26. </build>  

    配置完成后，执行mvn package即可打包。在target目录下会生成两个jar包，注意不是original-xxx.jar文件，而是另外一个。和maven-assembly-plugin一样，生成的jar文件包含了所有依赖，所以可以直接运行。

    如果项目中用到了Spring Framework，将依赖打到一个jar包中，运行时会出现读取XML schema文件出错。原因是Spring Framework的多个jar包中包含相同的文件spring.handlers和spring.schemas，如果生成一个jar包会互相覆盖。为了避免互相影响，可以使用AppendingTransformer来对文件内容追加合并：

      1. <build>  
      2.     <plugins>  
      3.   
      4.         <plugin>  
      5.             <groupId>org.apache.maven.plugins</groupId>  
      6.             <artifactId>maven-shade-plugin</artifactId>  
      7.             <version>2.4.1</version>  
      8.             <executions>  
      9.                 <execution>  
      10.                     <phase>package</phase>  
      11.                     <goals>  
      12.                         <goal>shade</goal>  
      13.                     </goals>  
      14.                     <configuration>  
      15.                         <transformers>  
      16.                             <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">  
      17.                                 <mainClass>com.xxg.Main</mainClass>  
      18.                             </transformer>  
      19.                             <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">  
      20.                                 <resource>META-INF/spring.handlers</resource>  
      21.                             </transformer>  
      22.                             <transformer implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">  
      23.                                 <resource>META-INF/spring.schemas</resource>  
      24.                             </transformer>  
      25.                         </transformers>  
      26.                     </configuration>  
      27.                 </execution>  
      28.             </executions>  
      29.         </plugin>  
      30.   
      31.     </plugins>  
      32. </build>  

    自己代码中的shade+assembly:

    pom.xml:

     1         <plugin>
 2                 <groupId>org.apache.maven.plugins</groupId>
 3                 <artifactId>maven-shade-plugin</artifactId>
 4                 <dependencies>
 5                     <dependency>
 6                         <groupId>org.springframework.boot</groupId>
 7                         <artifactId>spring-boot-maven-plugin</artifactId>
 8                         <version>1.5.17.RELEASE</version>
 9                     </dependency>
10                 </dependencies>
11                 <configuration>
12                     <shadedArtifactAttached>true</shadedArtifactAttached>
13                     <keepDependenciesWithProvidedScope>true</keepDependenciesWithProvidedScope>
14                     <createDependencyReducedPom>false</createDependencyReducedPom>
15                     <finalName>demo-web-server-shade</finalName>
16                     <filters>
17                         <filter>
18                             <artifact>*:*</artifact>
19                             <excludes>
20                                 <exclude>META-INF/*.SF</exclude>
21                                 <exclude>META-INF/*.DSA</exclude>
22                                 <exclude>META-INF/*.RSA</exclude>
23                             </excludes>
24                         </filter>
25                     </filters>
26                 </configuration>
27                 <executions>
28                     <execution>
29                         <phase>package</phase>
30                         <goals>
31                             <goal>shade</goal>
32                         </goals>
33                         <configuration>
34                             <transformers>
35                                 <transformer
36                                     implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
37                                     <resource>META-INF/spring.handlers</resource>
38                                 </transformer>
39                                 <transformer
40                                     implementation="org.springframework.boot.maven.PropertiesMergingResourceTransformer">
41                                     <resource>META-INF/spring.factories</resource>
42                                 </transformer>
43                                 <transformer
44                                     implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
45                                     <resource>META-INF/spring.schemas</resource>
46                                 </transformer>
47                                 <transformer
48                                     implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer" />
49                                 <transformer
50                                     implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
51                                     <mainClass>com.my.demo.httpserver.WebServerApplication</mainClass>
52                                 </transformer>
53                             </transformers>
54                         </configuration>
55                     </execution>
56                 </executions>
57             </plugin>
58 
59             <plugin>
60                 <groupId>org.apache.maven.plugins</groupId>
61                 <artifactId>maven-assembly-plugin</artifactId>
62                 <executions>
63                     <execution>
64                         <id>assemble</id>
65                         <goals>
66                             <goal>single</goal>
67                         </goals>
68                         <phase>package</phase>
69                         <configuration>
70                             <descriptors>
71                                 <descriptor>assembly.xml</descriptor>
72                             </descriptors>
73                         </configuration>
74                     </execution>
75                 </executions>
76             </plugin>

    assembly.xml:

     <?xml version="1.0" encoding="utf-8"?>

<assembly>
  <id>assembly</id>
  <includeBaseDirectory>false</includeBaseDirectory>
  <formats> 
    <format>zip</format> 
  </formats>  
  <fileSets> 
    <!-- <fileSet>
      <directory>src/main/resources/bin</directory>
      <includes> 
        <include>start.sh</include>
        <include>env.sh</include>
        <include>stop.sh</include>
      </includes>  
      <fileMode>0755</fileMode>  
      <outputDirectory>/</outputDirectory>
    </fileSet> -->
    <fileSet>
      <directory>src/main/resources/configsec</directory>
      <includes>
        <include>important.properties</include>
      </includes>
      <outputDirectory>configsec/</outputDirectory>
    </fileSet>
    <fileSet>
      <directory>src/main/resources/lib</directory>
      <includes>
        <include>quasar-core-0.7.9-jdk8.jar</include>
      </includes>
      <outputDirectory>/</outputDirectory>
    </fileSet>
  </fileSets>
  <files> 
    <file> 
      <source>${project.build.directory}/demo-web-server-shade.jar</source>
      <outputDirectory>/</outputDirectory>
    </file> 
  </files> 
</assembly>

    转自：https://blog.csdn.net/daiyutage/article/details/53739452

    参考资料：

    https://yq.aliyun.com/articles/308777

    maven-shade-plugin：https://my.oschina.net/u/2377110/blog/1584205

    maven-assembly-plugin：https://www.jianshu.com/p/14bcb17b99e0 https://blog.csdn.net/liupeifeng3514/article/details/79777976
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  • 原文地址：https://www.cnblogs.com/fnlingnzb-learner/p/11119799.html
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