解决java.lang.NoClassDefFoundError第三方依赖jar包问题/把本地jar打包进war包问题

柔情只为你懂 2021-09-21 08:14 972阅读 0赞

这种报错的原因是本地的jar包没有被maven构建项目时打包, 解决办法时配置pom文件将本地jar包打包进项目.

### 文章目录 ###

*   *   *  报错信息
         *  报错原因
         *  解决
         *   *  第一步: pom.xml配置dependency依赖
             *  第二步: 在pom.xml的标签中加入
             *  第三步测试

### 报错信息 ###

`java.lang.NoClassDefFoundError`  
`java.lang.ClassNotFoundException`  
依赖的clss文件没有找到

Caused by: java.lang.NoClassDefFoundError: com/taobao/api/ApiException
    	at java.lang.Class.getDeclaredMethods0(Native Method)
    	at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
    	at java.lang.Class.getDeclaredMethods(Class.java:1975)
    	at org.springframework.util.ReflectionUtils.getDeclaredMethods(ReflectionUtils.java:489)
    	... 64 more
    Caused by: java.lang.ClassNotFoundException: com.taobao.api.ApiException
    	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1358)
    	at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1180)
    	... 68 more

2020-06-05 22:15:43,175 944    [on(3)-127.0.0.1] WARN  pport.XmlWebApplicationContext  - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userAPI': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.marchsoft.dingtalk.UserAPI] from ClassLoader [ParallelWebappClassLoader
      context: class_schedule_war
      delegate: false
    ----------> Parent Classloader:
    java.net.URLClassLoader@515f550a
    ]
    2020-06-05 22:15:43,181 950    [on(3)-127.0.0.1] ERROR work.web.context.ContextLoader  - Context initialization failed
    org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'userAPI': Lookup method resolution failed; nested exception is java.lang.IllegalStateException: Failed to introspect Class [com.marchsoft.dingtalk.UserAPI] from ClassLoader [ParallelWebappClassLoader
      context: class_schedule_war
      delegate: false
    ----------> Parent Classloader:
    java.net.URLClassLoader@515f550a

**报错图片**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 1]

### 报错原因 ###

**本地导入jar包**  
![在这里插入图片描述][20200605222201430.png]

**tomcat运行构建的项目WEB-INF/lib下并没我导入的jar包**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 2]

### 解决 ###

#### 第一步: pom.xml配置dependency依赖 ####

以下是下载的钉钉sdk, 在maven中导入的依赖.

<dependency>
         <groupId>com.taobao.top</groupId>
         <artifactId>top-api-sdk-dev</artifactId>
         <version>ding-open-mc-SNAPSHOT</version>
         <scope>system</scope>
         <systemPath>${project.basedir}/src/lib/taobao-sdk-java-auto_1479188381469-20200525.jar</systemPath>
     </dependency>

**scope:** 表示系统运行时依赖此jar  
**systemPath:** 指本地jar的位置(绝对路径); `${project.basedir}`是项目路径  
![在这里插入图片描述][20200605223207536.png]

#### 第二步: 在pom.xml的标签中加入 ####

<plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-war-plugin</artifactId>
         <configuration>
             <warName>${project.artifactId}</warName>
             <webResources>
                 <resource>
                     <directory>src/lib/</directory>
                     <targetPath>WEB-INF/lib</targetPath>
                     <includes>
                         <include>**/*.jar</include>
                     </includes>
                 </resource>
             </webResources>
         </configuration>
     </plugin>

**固定内容标签:** groupId、atrifactId、warName

**directory：** 为本地jar路径  
**targetPath：** 打包路径  
**include:** `**/*.jar` 表示指定路径下所有jar

#### 第三步测试 ####

*  注意及时清理之前构建的项目残留文件
 *  构建时可以尝试maven构建命令,然后运行tomcat  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 3]
 *  **重新构建后，可以看到本地jar已经被打包到项目里**  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 4]  
    能力有限，若有问题欢迎评论指正。

--------------------

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[20200605222201430.png]: /images/20210920/ba6f243474384104a8eb885921077abe.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 2]: /images/20210920/42fc3547b86b456dac73698276dbb637.png
[20200605223207536.png]: /images/20210920/73080d095e7440b3aba2c9c85b8802c3.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 3]: /images/20210920/2807886163984ae49c667a17c177d9a2.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MzIxNzk0Mg_size_16_color_FFFFFF_t_70 4]: /images/20210920/bdaf2135dbc94628826332ae880c974c.png
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