配置mybatis 出现的异常

Question

网上找的结果都没解决 例如
第一个解决方法 失败

我的代码

第二个解决方法 连接 数据库 失败

matches criteria [is assignable to Object] 
Exception in thread "main" org.apache.ibatis.exceptions.PersistenceException: 
### Error building SqlSession.
### The error may exist in com/itheima/mapper/UserMapper.java (best guess)
### Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.binding.BindingException: Type interface com.itheima.mapper.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)
    at com.itheima.MyBatisDemo.main(MyBatisDemo.java:24)
Caused by: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.binding.BindingException: Type interface com.itheima.mapper.UserMapper is already known to the MapperRegistry.
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:122)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.parse(XMLConfigBuilder.java:99)
    at org.apache.ibatis.session.SqlSessionFactoryBuilder.build(SqlSessionFactoryBuilder.java:78)
    ... 2 more
Caused by: org.apache.ibatis.binding.BindingException: Type interface com.itheima.mapper.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:106)
    at org.apache.ibatis.binding.MapperRegistry.addMappers(MapperRegistry.java:118)
    at org.apache.ibatis.session.Configuration.addMappers(Configuration.java:815)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.mapperElement(XMLConfigBuilder.java:367)
    at org.apache.ibatis.builder.xml.XMLConfigBuilder.parseConfiguration(XMLConfigBuilder.java:120)
    ... 4 more

Answer 1

将mappers里面的两行删除，换成我这个，其中的name值就是你的mapper所在的包名，这样就不需要多次配置

<mappers>
        <!--Mapper代理方式-->
        <package name="com.itheima.mapper"/>
    </mappers>