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Mybatis使用xml及纯注解实现增删改查操作

article 2024/12/22 8:36:50

文章目录

MyBatis 的基本使用
- 1 案例讲解：使用xml文件配置，实现对数据的增删改查，MyBatis----xml配置使用
- - （1）代码目录：
  - 导入项目依赖
  - （2）创建pojo类：
  - （3）编写mybatis 核心配置文件： mybatis-config.xml
  - （4）编写SQL映射文件：DeptMapper.xml
  - （4）编写工具类：MyUtils.java
  - （5）开始使用：App.java
- 2 案例演示：MyBatis的纯注解开发，实现对数据的增删改查。
- - （1）将 DeptMapper.xml 文件全部进行注释即可
  - （2）将工具类 MyUtils.java 保留以下部分，其他注释掉即可
  - （3）接口 DeptMapper 使用注解
  - （4）App.java 进行运行
- 由以上2个案例，可以体会到纯注解开发的快捷之处，希望大家好好体会。

MyBatis 的基本使用

什么是 MyBatis ？

MyBatis 是一款优秀的持久层框架，用于简化 JDBC 开发
MyBatis 本是 Apache 的一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code，并且改名为MyBatis 。2013年11月迁移到Github官网：https://mybatis.org/mybatis-3/zh/index.html

1 案例讲解：使用xml文件配置，实现对数据的增删改查，MyBatis----xml配置使用

（1）代码目录：

在这里插入图片描述

id 列为自增长。

导入项目依赖

pom.xml 文件：

<?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>com.xbf</groupId>
    <artifactId>mybatis</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.34</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.33</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.9</version>
        </dependency>
    </dependencies>

</project>

（2）创建pojo类：

package com.xbf.pojo;

public class Dept implements java.io.Serializable{
    private int id;
    private String name;
    private int age;
    private String sex;
    private String address;

    public String getName() {
        return name;
    }

    public int getId() {
        return id;
    }

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

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Dept{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

（3）编写mybatis 核心配置文件： 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>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <!-- 数据库连接相关配置 ,db.properties文件中的内容-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/demo01?useSSL=true&amp;useUnicode=true&amp;
characterEncoding=GBK"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>


    <mappers>
        <package name="com.xbf.mapper"/>
    </mappers>

</configuration>

（4）编写SQL映射文件：DeptMapper.xml

<?xml version="1.0" encoding="UTF8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.xbf.mapper.DeptMapper">
    <!-- 根据id查询图书信息 -->
    <select id="selectAll" parameterType="Integer"
            resultType="com.xbf.pojo.Dept">
        SELECT * from table1
    </select>
<!--       新增-->
    <insert id="insertDept" parameterType="com.xbf.pojo.Dept">
        insert into table1(`name`,`age`,`sex`,`address`) values(#{name},#{age},#{sex},#{address})
    </insert>
<!-- 删除-->
    <delete id="deleteDept" parameterType="int">
        delete from table1 where id=#{id}
    </delete>
    <!-- 修改-->
    <update id="updateDept" parameterType="com.xbf.pojo.Dept">
        update table1 set name=#{name},age=#{age},sex=#{sex},address=#{address} where id=#{id}
    </update>
</mapper>

（4）编写工具类：MyUtils.java

package com.xbf.utils;

import com.xbf.mapper.DeptMapper;
import com.xbf.pojo.Dept;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyUtils {
    public static SqlSession getSqlSession() {
        SqlSession sqlSession = null;

        try {
            InputStream is =
                    Resources.getResourceAsStream("mybatis-config.xml");

            SqlSessionFactory build =
                    new SqlSessionFactoryBuilder().build(is);
            sqlSession = build.openSession();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        return sqlSession;
    }

    //修改
    public static void updateDept(int id, String name, int age, String sex,
                                  String address, DeptMapper mapper, SqlSession sqlSession) {
        //SqlSession sqlSession = getSqlSession();
        Dept dept = new Dept();
        dept.setId(id);
        dept.setName(name);
        dept.setAge(age);
        dept.setSex(sex);
        dept.setAddress(address);
        mapper.updateDept(dept);
        if (sqlSession != null) {
            sqlSession.commit();
            // sqlSession.close();
        }
        System.out.println("修改成功");
    }

    //插入数据
    public static void insertDept(String name, int age, String sex,
                                  String address, DeptMapper mapper, SqlSession sqlSession) {

        //SqlSession sqlSession = getSqlSession();
        Dept dept = new Dept();
        dept.setName(name);
        dept.setAge(age);
        dept.setSex(sex);
        dept.setAddress(address);
        mapper.insertDept(dept);
        if (sqlSession != null) {
            sqlSession.commit();
            // sqlSession.close();
        }
        System.out.println("插入成功");
    }

    //删除数据
    public static void deleteDept(int id, DeptMapper mapper, SqlSession sqlSession) {

        //SqlSession sqlSession = getSqlSession();
        mapper.deleteDept(id);
        if (sqlSession != null) {
            sqlSession.commit();
            // sqlSession.close();
        }
        System.out.println("删除成功");
    }
}

（5）开始使用：App.java

package com.xbf;

import com.xbf.mapper.DeptMapper;
import com.xbf.pojo.Dept;
import com.xbf.utils.MyUtils;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class App {
    public static void print(DeptMapper mapper) {
        List<Dept> depts = mapper.selectAll();
        for (Dept dept : depts) {
            System.out.println(dept);
        }
    }

    public static void main(String[] args) throws IOException {
        SqlSession sqlSession = MyUtils.getSqlSession();
        DeptMapper mapper = sqlSession.getMapper(DeptMapper.class);
        //查询
        print(mapper);

        //增加
        MyUtils.insertDept("熊21", 23, "男", "北京", mapper,sqlSession);
        print(mapper);

        //修改
        MyUtils.updateDept(12, "熊5", 23, "男", "北京", mapper, sqlSession);
        print(mapper);

        //删除
        MyUtils.deleteDept(11, mapper, sqlSession);
        print(mapper);

        sqlSession.close();


    }
}

运行结果：注意，下图结果为博主多次测试的结果，和上面代码运行结果不一定完全符合。

在这里插入图片描述

2 案例演示：MyBatis的纯注解开发，实现对数据的增删改查。

在上一个案例的基础上进行修改：

（1）将 DeptMapper.xml 文件全部进行注释即可

（2）将工具类 MyUtils.java 保留以下部分，其他注释掉即可

package com.xbf.utils;

import com.xbf.mapper.DeptMapper;
import com.xbf.pojo.Dept;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MyUtils {
    public static SqlSession getSqlSession() {
        SqlSession sqlSession = null;

        try {
            InputStream is =
                    Resources.getResourceAsStream("mybatis-config.xml");

            SqlSessionFactory build =
                    new SqlSessionFactoryBuilder().build(is);
            sqlSession = build.openSession();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        return sqlSession;
    }
}

（3）接口 DeptMapper 使用注解

package com.xbf.mapper;

import com.xbf.pojo.Dept;
import org.apache.ibatis.annotations.*;

import java.util.List;

public interface DeptMapper {
    @Select("select * from table1")
    //查询所有
    List<Dept> selectAll();

    //添加
    @Insert("insert into table1(`name`,`age`,`sex`,`address`) values(#{name},#{age},#{sex},#{address})")
    int insertDept(@Param(value = "name") String name,
                   @Param(value = "age") int age,
                   @Param(value = "sex") String sex,
                   @Param(value = "address") String address);
    //@Param(value="name")String name,@Param(value="hobby")String hobby

    //根据id 删除记录
    @Delete("delete from table1 where id=#{id}")
    int deleteDept(Integer id);

    //根据id修改信息
    @Update("update table1 set name=#{name},age=#{age},sex=#{sex},address=#{address} where id=#{id}")
    int updateDept(@Param(value = "id") Integer id,
            @Param(value = "name") String name,
                   @Param(value = "age") int age,
                   @Param(value = "sex") String sex,
                   @Param(value = "address") String address);

}

（4）App.java 进行运行

package com.xbf;

import com.xbf.mapper.DeptMapper;
import com.xbf.pojo.Dept;
import com.xbf.utils.MyUtils;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class App {
    public static void print(DeptMapper mapper) {
        List<Dept> depts = mapper.selectAll();
        for (Dept dept : depts) {
            System.out.println(dept);
        }
    }

    public static void main(String[] args) throws IOException {
        SqlSession sqlSession = MyUtils.getSqlSession();
        DeptMapper mapper = sqlSession.getMapper(DeptMapper.class);

        //查询
        print(mapper);
        System.out.println("查询成功");

        //增加
        mapper.insertDept("熊21", 23, "男", "北京");
        print(mapper);
        sqlSession.commit();
        System.out.println("增加成功");

        //删除
        mapper.deleteDept(12);
        print(mapper);
        sqlSession.commit();
        System.out.println("删除成功");

        //修改
        mapper.updateDept(2, "熊10", 23, "男", "萍乡");
        print(mapper);
        sqlSession.commit();
        System.out.println("修改成功");

        sqlSession.close();
    }
}