JAVA高级面试进阶训练营视频教程

admin · 发表于 2021-4-11 17:26:53

今天在用mybatis自动生成代码之后遇到了一个错误：

 
        org.apache.ibatis.exceptions.PersistenceException : 
       
        ### Error building SqlSession. 
       
        ### The error may exist in com/erp/webservice/mapper/UsersMapper.xml 
       
        ### The error occurred  
        while 
        processing mapper_resultMap[BaseResultMap] 
       
        ### Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.lang.RuntimeException: Error parsing Mapper XML. Cause: java.lang.IllegalArgumentException : Result Maps collection already contains value  
        for 
        com.erp.webservice.inter.UsersMapper.BaseResultMap 
       
        at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java: 
        23 
        ) 
       
        at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java: 
        51 
        ) 
       
        at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java: 
        35 
        ) 
       
        at com.erp.webservice.test.Test.<clinit>( Test.java: 
        22 
        ) 
       
        Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: java.lang.RuntimeException: Error parsing Mapper XML. Cause: java.lang.IllegalArgumentException : Result Maps collection already contains value  
        for 
        com.erp.webservice.inter.UsersMapper.BaseResultMap 
       
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java: 
        107 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java: 
        89 
        ) 
       
        at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java: 
        49 
        ) 
       
        ...  
        2 
        more 
       
        Caused by: java.lang.RuntimeException: Error parsing Mapper XML. Cause: java.lang.IllegalArgumentException : Result Maps collection already contains value  
        for 
        com.erp.webservice.inter.UsersMapper.BaseResultMap 
       
        at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java: 
        113 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLMapperBuilder.parse(XMLMapperBuilder.java: 
        88 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.mapperElement(XMLConfigBuilder.java: 
        325 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java: 
        105 
        ) 
       
        ...  
        4 
        more 
       
        Caused by: java.lang.IllegalArgumentException: Result Maps collection already contains value  
        for 
        com.erp.webservice.inter.UsersMapper.BaseResultMap 
       
        at org.apache.ibatis.session.Configuration$StrictMap.put(Configuration.java: 
        710 
        ) 
       
        at org.apache.ibatis.session.Configuration$StrictMap.put(Configuration.java: 
        682 
        ) 
       
        at org.apache.ibatis.session.Configuration.addResultMap(Configuration.java: 
        473 
        ) 
       
        at org.apache.ibatis.builder.MapperBuilderAssistant.addResultMap(MapperBuilderAssistant.java: 
        204 
        ) 
       
        at org.apache.ibatis.builder.ResultMapResolver.resolve(ResultMapResolver.java: 
        44 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLMapperBuilder.resultMapElement(XMLMapperBuilder.java: 
        277 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLMapperBuilder.resultMapElement(XMLMapperBuilder.java: 
        244 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLMapperBuilder.resultMapElements(XMLMapperBuilder.java: 
        236 
        ) 
       
        at org.apache.ibatis.builder.xml.XMLMapperBuilder.configurationElement(XMLMapperBuilder.java: 
        109 
        ) 
       
        ...  
        7 
        more 
       
        Exception in thread  
        "main" 
        java.lang.NullPointerException 
       
        at com.erp.webservice.test.Test.main( Test.java: 
        29 
        )

后来发现是我运行了多次自动生成代码的程序，导致了com/erp/webservice/mapper/UsersMapper.xml的内容多出来很多，原来自动生成代码的时候生成的XML代码不是覆盖原来的，而是附加的XML的尾部的。

第一次运行自动生成代码程序：

第二次运行自动生成代码程序：

看看，XML文件明显大了很多，只要删掉原来的XML然后重新运行自动生成代码的程序即可。

或者去工作空间吧生成的东西都删除一边重新生成

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JAVA高级面试进阶训练营视频教程

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mybatis generator自动生成代码报The error occurred while processing mapper_resultMap[BaseResultMap]错误的解决方法