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

今天在用mybatis自动生成代码之后遇到了一个错误：

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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