Mybatis学习笔记

首先要有jar包：mybatis-3.2.8.jar,以及连接数据库的jar包,根据连接数据库的不同而选择。

数据库中建表,项目中建model:User.java,同时建立这个User 的映射文件 User.xml

< ?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">

< mapper namespace="com.gch.UserMapper">
    <select id="selectUserByID"parameterType="int" resultType="User">
        select * from `user` where id =#{id}
    </select>
< /mapper>

设置mybatis配置文件:Configuration.xml

< ?xml version="1.0" encoding="UTF-8" ?>
< !DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
< configuration>

<!--别名-->
   <typeAliases> 
        <typeAlias alias="User"type="com.gch.model.User"/> 
    </typeAliases> 

    <environments default="development">
        <environmentid="development">
        <transactionManagertype="JDBC"/>
           <dataSource type="POOLED">
            <propertyname="driver" value="com.mysql.jdbc.Driver"/>
            <propertyname="url" value="jdbc:mysql://1192.168.254.128:3306/mybatis" />
            <propertyname="username" value="root"/>
            <propertyname="password" value="root"/>
           </dataSource>
        </environment>
    </environments>
    
    <mappers>
        <mapperresource="com/gch/model/User.xml"/>
    </mappers>
< /configuration>

测试的主要代码：

Reader reader   = Resources.getResourceAsReader("Configuration.xml");
SqlSessionFactory  sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
SqlSession session =sqlSessionFactory.openSession();
User user = (User)session.selectOne("com.gch.models.UserMapper.selectUserByID",1);
System.out.println(user.getUserAddress());

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以上的代码，简单的实现mybatis操作数据，但离实际的工作开发有点远

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使用接口方式：

建立接口类 IUserOperation.java

public interface IUserOperation {    
    public User selectUserByID(int id); 
}

修改<mapper namespace="com.gch.dao.inter.IUserOperation">

请注意，这里面有一个方法名selectUserByID 必须与 User.xml 里面配置的select 的id 对应（<select id="selectUserByID"）

测试的主要代码：

IUserOperationuserOperation=session.getMapper(IUserOperation.class);
User user =userOperation.selectUserByID(1);

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