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最新推荐文章于 2025-06-13 15:06:56 发布

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最新推荐文章于 2025-06-13 15:06:56 发布

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文章标签： mybatis java 开发语言

本文链接：https://blog.youkuaiyun.com/weixin_44434594/article/details/130888816

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文章展示了如何使用MyBatis框架进行简单操作，包括创建User实体类，配置MyBatis的核心XML文件，定义UserMapper接口，编写mapper.xml查询语句，以及最后进行测试，从数据库中获取User列表。

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第一个程序MyBatis

1.编写实体类

package com.jiang.pojo;

import lombok.Data;

@Data
public class User {
    private  int id;
    private String username;
    private String password;
    private String gender;
    private String addr;
    
}

2.编写核心配置文件

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

<!--configuration核心配置文件-->

<configuration>
    <typeAliases>
         <package name="com.jiang.pojo" />
    </typeAliases>
    <environments default="development">
      <environment id="development">
        <transactionManager type="JDBC"/>
         <dataSource type="POOLED">
           <property name="driver" value="com.mysql.jdbc.Driver"/>
           <property name="url" value="jdbc:mysql://localhost:3306/mybatis?tb_user"/>
           <property name="username" value="root"/>
           <property name="password" value="123456"/>
       </dataSource>
      </environment>
   </environments>

    <mappers>
        <mapper class="com.jiang.mapper.UserMapper"/>
    </mappers>
</configuration>

3.编写接口

package com.jiang.mapper;

import com.jiang.pojo.User;

import java.util.List;

public interface UserMapper {
    public List<User> selectUser();
}

4.编写mapper.xml文件

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

<!--configuration核心配置文件-->
<mapper namespace="com.jiang.mapper.UserMapper">

   <select id="selectUser" resultType="user">
       select * from tb_user;
   </select>
</mapper>

5.测试

import com.jiang.mapper.UserMapper;
import com.jiang.pojo.User;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
import org.apache.ibatis.io.Resources;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyTest {
    @Test
    public void test() throws IOException {
        String resources = "mybatis-config.xml";
        InputStream in = Resources.getResourceAsStream(resources);

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);

        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = mapper.selectUser();
        for (User user : userList) {
            System.out.println(user);
            
        }

        sqlSession.close();
    }
}