异常背景:

在使用mybatis的时候,出现的异常

异常信息:

The error may exist in com/zuoyueer/dao/UserMapper.java (best guess)
### Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.binding.BindingException: Type interface com.zuoyueer.dao.UserMapper is already known to the MapperRegistry.

	at org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:30)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:80)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:64)
	Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.binding.BindingException: Type interface com.zuoyueer.dao.UserMapper is already known to the MapperRegistry.
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:121)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:99)
	at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:78)
	... 24 more
Caused by: org.apache.ibatis.binding.BindingException: Type interface com.zuoyueer.dao.UserMapper is already known to the MapperRegistry.
	at org.apache.ibatis.binding.MapperRegistry.addMapper(MapperRegistry.java:63)
	at org.apache.ibatis.binding.MapperRegistry.addMappers(MapperRegistry.java:97)
	at org.apache.ibatis.binding.MapperRegistry.addMappers(MapperRegistry.java:105)
	at org.apache.ibatis.session.Configuration.addMappers(Configuration.java:737)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.mapperElement(XMLConfigBuilder.java:364)
	at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:119)
	... 26 more

主要信息是:Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.binding.BindingException: Type interface com.zuoyueer.dao.UserMapper is already known to the MapperRegistry.

异常分析

• 全局配置文件配置出现异常,下面的是: SqlMapConfig.xml全局配置文件中的一部分

  <mappers>
        <!--引入一个映射文件-->
        <mapper resource="com/zuoyueer/dao/UserMapper.xml"></mapper>
        <!--映射文件和接口的名字一致,路径一致,就可以直接引入name属性值表示的包下的全部映射文件-->
        <package name="com.zuoyueer.dao"/>
    </mappers>

同时配置了一个映射文件,和包映射文件,两者冲突了

• 映射文件配置出现异常