MyBatis 基于接口编程学习笔记

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异常：

Exception in thread "main" org.apache.ibatis.binding.BindingException: Type interface com.yihaomen.mybatis.inter.IUserOperation is not known to the MapperRegistry.
at org.apache.ibatis.binding.MapperRegistry.getMapper(MapperRegistry.java:42)
at org.apache.ibatis.session.Configuration.getMapper(Configuration.java:655)
at org.apache.ibatis.session.defaults.DefaultSqlSession.getMapper(DefaultSqlSession.java:218)
at com.yihaomen.test.Test.main(Test.java:33)

原因：User.xml 文件中 mapper中：错误如下红色字体为错误命名空间，接口编程中应对应接口所在路径，绿色为正确配置。

<--------?xml version="1.0" encoding="UTF-8" ?>
<--------!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<--------!--namespace="com.yihaomen.mybatis.inter.IUserOperation"  -->
<--------mapper namespace="com.yihaomen.mybatis.models.UserMapper" >
    <--------select id="selectUserByID" parameterType="int" resultType="User">
        select * from `user` where id = #{id}
    <--------/select>
<--------/mapper>

注意：增加，更改，删除的时候要调用session.commit()，这样才会真正对数据库进行操作，否则是没有提交的。

多对一遇到的异常：在xml文件中多方的

中type 不能直接写Article 而要写全其路径：com.yihaomen.mybatis.model.Article

org.apache.ibatis.exceptions.PersistenceException:
### Error building SqlSession.
### The error may exist in com/yihaomen/mybatis/model/User.xml
### The error occurred while processing mapper_resultMap[resultUserArticleList]
### Cause: org.apache.ibatis.builder.BuilderException: Error parsing SQL Mapper Configuration. Cause: org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: org.apache.ibatis.builder.BuilderException: Error resolving class. Cause: org.apache.ibatis.type.TypeException: Could not resolve type alias 'Article'. Cause: java.lang.ClassNotFoundException: Cannot find class: Article
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.yihaomen.test.Test.(Test.java:22)……
... 13 more
Exception in thread "main" java.lang.NullPointerException
at com.yihaomen.test.Test.getUserArticles(Test.java:142)
at com.yihaomen.test.Test.main(Test.java:35)

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