如何优雅依赖多个版本的jar包？

谁践踏了优雅 2023-09-24 14:13 30阅读 0赞

## 问题现状 ##

由于是一个迭代比较久的项目，项目中已经存在poi-tl 1.5.x的依赖，poi-tl v1.5.x是构建在Apache poi3.16上的版本，而我们现在要使用到easyexcel来处理导出，而easyexcel最低的Apache poi版本要求是4.1.2，将项目中已有poi的3.16升级到4.12时，旧代码出错，但是不升级就无法使用easyexcel。

## 解决思路 ##

解决问题思路无非就是两种：

1.  将项目中已有的poi3.16升级到4.12，解决升级后代码出错的地方；
    
    优点：jar包依赖清晰，在代码改动量可控的情况下，推荐使用该方式；
    
    缺点：代码改动量大，工作量大，而且容易对之前的功能带来不稳定因素；
2.  使用maven-shade-plugin插件来解决，让项目依赖多个版本的poi版本；
    
    优点：对原来的功能无影响，代码改动量小；
    
    缺点：jar依赖变大，因为依赖了同一个依赖的2个版本；jar包依赖不那么清晰优雅；

今天文章主角就是第2种方式。

**它的核心思路就是把easyexcel中的高版本poi包改个名字，同时easyexcel中引用的地方也改名（自动），并且代码中用高本版的地方也改个名（手动）。**

## 解决问题 ##

1.  创建一个空maven项目，项目名称为jarjar，引入easyexcel的依赖；
    
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>3.1.1</version>
        </dependency>
    
    查看其依赖的poi版本
    
    ![30253633b99e69bf850d9174b1b1656e.png][]
    
    easyexcel poi版本
2.  引入插件并且配置好修改的方式；
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-shade-plugin</artifactId>
                    <version>3.2.4</version>
                    <executions>
                        <execution>
                            <phase>package</phase>
                            <goals>
                                <goal>shade</goal>
                            </goals>
                            <configuration>
                                <createDependencyReducedPom>true</createDependencyReducedPom>
                                <relocations>
                                    <relocation>
                                        
                                            <pattern>org.apache.poi</pattern>
                                            
                                            <shadedPattern>shaded.org.apache.poi</shadedPattern>
                                        </relocation>
        
                                        
                                        <relocation>
                                            
                                            <pattern>com.deepoove.poi.XWPFTemplate</pattern>
                                            
                                            <shadedPattern>shaded.com.deepoove.poi.XWPFTemplate</shadedPattern>
                                        </relocation>
                                    </relocations>
                                </configuration>
                            </execution>
                        </executions>
                    </plugin>
                </plugins>
            </build>改名前 -->
                                        <pattern>org.apache.poi</pattern>
                                        
                                        <shadedPattern>shaded.org.apache.poi</shadedPattern>
                                    </relocation>
                                </relocations>
                            </configuration>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </build>
    
    较为完整的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>org.example</groupId>
            <artifactId>jarjar</artifactId>
            <version>1.0-SNAPSHOT</version>
        
            <dependencies>
                <dependency>
                    <groupId>com.alibaba</groupId>
                    <artifactId>easyexcel</artifactId>
                    <version>3.1.1</version>
                </dependency>
            </dependencies>
        
            <properties>
                <maven.compiler.source>8</maven.compiler.source>
                <maven.compiler.target>8</maven.compiler.target>
            </properties>
        
            <build>
                <plugins>
                    <plugin>
                        <groupId>org.apache.maven.plugins</groupId>
                        <artifactId>maven-shade-plugin</artifactId>
                        <version>3.2.4</version>
                        <executions>
                            <execution>
                                <phase>package</phase>
                                <goals>
                                    <goal>shade</goal>
                                </goals>
                                <configuration>
                                    <createDependencyReducedPom>true</createDependencyReducedPom>
                                    <relocations>
                                        <relocation>
                                            
                                            <pattern>org.apache.poi</pattern>
                                            
                                            <shadedPattern>shaded.org.apache.poi</shadedPattern>
                                        </relocation>
        
                                        
                                        <relocation>
                                            
                                            <pattern>com.deepoove.poi.XWPFTemplate</pattern>
                                            
                                            <shadedPattern>shaded.com.deepoove.poi.XWPFTemplate</shadedPattern>
                                        </relocation>
                                    </relocations>
                                </configuration>
                            </execution>
                        </executions>
                    </plugin>
                </plugins>
            </build>
        
        </project>
3.  打出jar包；
    
    执行`mvn package`，如果是IDEA直接双击Lifecycle中的`package`就行了。
    
    ![cabe9fb8946a8f6ac6d902b238dede14.png][]
    
    打出jar包
    
    这时target目录中会有两个包，一个是original开头的原本包，因为我们没有新建类，所以这个包是空的。另一个是和`artifactId-version.jar`的包，`artifactId`和`version`是本项目创建时填写的坐标。
    
    如图，我的这个maven项目叫jarjar，版本是1.0：
    
    找到指定的jar包
4.  依赖本地jar，运行项目；
    
        <dependency>
                    <groupId>org.example</groupId>
                    <artifactId>jarjar</artifactId>
                    <version>1.0-SNAPSHOT</version>
                    <scope>system</scope>
                    <systemPath>${project.basedir}/src/main/java/lib/jarjar-1.0-SNAPSHOT.jar</systemPath>
        </dependency>
    
         <build>
           <resources>
            <resource>
              <directory>lib</directory>
              <targetPath>/BOOT-INF/lib/</targetPath>
              <includes>
                <include>**/*.jar</include>
              </includes>
            </resource>
           </resources>
         </build>
    
    1.  处理打包
    2.  自定义目录，这里在project的根目录新建lib文件夹，将jar放进去
    3.  引入jar包
        
        ![343f184040c9330c2fa402271f41a81c.png][]
        
        jarjar项目的pom信息

**至此，已经无损的引入了easyexcel依赖，easyexcel中引用的地方也改名（自动），并且代码中用高本版的地方也改个名（手动）。**

[30253633b99e69bf850d9174b1b1656e.png]: https://img-blog.csdnimg.cn/img_convert/30253633b99e69bf850d9174b1b1656e.png
[cabe9fb8946a8f6ac6d902b238dede14.png]: https://img-blog.csdnimg.cn/img_convert/cabe9fb8946a8f6ac6d902b238dede14.png
[343f184040c9330c2fa402271f41a81c.png]: https://img-blog.csdnimg.cn/img_convert/343f184040c9330c2fa402271f41a81c.png