MyBatis的增删改查操作(详细代码)

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1.pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>MyBatis-Demo1</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>


</project>

2.User

package com.jkj.domain;

public class User { 
    private int id;
    private String username;
    private String password;

    public int getId() { 
        return id;
    }

    public void setId(int id) { 
        this.id = id;
    }

    public String getUsername() { 
        return username;
    }

    public void setUsername(String username) { 
        this.username = username;
    }

    public String getPassword() { 
        return password;
    }

    public void setPassword(String password) { 
        this.password = password;
    }

    @Override
    public String toString() { 
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

3.user数据表

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4.mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--configuration core file-->
       <configuration>
    <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/mybatisthree?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <!--加载sql映射文件-->
    <mappers>
        <mapper resource="com/jkj/mapper/UserMapper.xml"/>
    </mappers>
</configuration>

5.UserMapper.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="userMapper">
   <!-- 查询-->
    <select id="findAll" resultType="com.jkj.domain.User">
        select * from user
    </select>
   <!-- 插入-->
    <insert id="save" parameterType="com.jkj.domain.User">
        insert into user values(#{ id},#{ username},#{ password})
    </insert>
   <!-- 修改-->
    <update id="update" parameterType="com.jkj.domain.User">
        update user set username=#{ username},password=#{ password} where id=#{ id}
    </update>
   <!-- 删除-->
    <delete id="delete" parameterType="com.jkj.domain.User">
        delete from user where id=#{ id}
    </delete>

</mapper>

6.MyBatisTest测试类

package com.jkj.test;

import com.jkj.domain.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

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

public class MyBatisTest { 
    //查询
    @Test
    public void test() throws IOException { 
        //1.加载MyBatis的核心配置文件获取sqlSessionFactory
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.获取sqlSession,执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.执行sql
        List<User> users = sqlSession.selectList("userMapper.findAll");
        System.out.println(users);
        //4.释放资源
        sqlSession.close();
    }
    //插入
    @Test
    public void save() throws IOException { 
        //模拟User对象
        User user = new User();
        user.setUsername("科比");
        user.setPassword("123456");
        //1.加载MyBatis的核心配置文件获取sqlSessionFactory
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.获取sqlSession,执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.执行sql
       sqlSession.insert("userMapper.save",user);
       //4.提交事务
        sqlSession.commit();
        //5.释放资源
        sqlSession.close();
    }
    //修改
    @Test
    public void update() throws IOException { 
        //模拟User对象
        User user = new User();
        user.setId(5);
        user.setUsername("RC");
        user.setPassword("555555");
        //1.加载MyBatis的核心配置文件获取sqlSessionFactory
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.获取sqlSession,执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.执行sql
       sqlSession.update("userMapper.update",user);
        //4.提交事务
        sqlSession.commit();
        //5.释放资源
        sqlSession.close();
    }
    //删除
    //修改
    @Test
    public void delete() throws IOException { 
        //1.加载MyBatis的核心配置文件获取sqlSessionFactory
        InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.获取sqlSession,执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.执行sql
        sqlSession.delete("userMapper.delete",5);
        //4.提交事务
        sqlSession.commit();
        //5.释放资源
        sqlSession.close();
    }

}
  • 删除语句使用delete标签
  • Sql语句中使用#{任意字符串}方式引用传递的单个参数
  • 删除操作使用的API是sqlSession.delete(“命名空间.id”,Object)
  • 修改语句使用update标签
  • 修改操作使用的API是sqlSession.update(“命名空间.id”,实体对象)
  • 插入语句使用insert标签
  • 在映射文件中使用parameterType属性指定要插入的数据类型
  • Sql语句中使用#{实体属性名}方式引用实体中的属性值
  • 插入操作使用的API是sqlSession.insert(“命名空间.id”,实体对象);
  • 插入操作涉及数据库数据变化,所以要使用sqlSession对象显示的提交事务,即sqlSession.commit()
本文为互联网自动采集或经作者授权后发布,本文观点不代表立场,若侵权下架请联系我们删帖处理!文章出自:https://blog.csdn.net/qq_43514330/article/details/125584866
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