MyBatis01

MyBatis01

MyBatis（原名为iBatis）是一个开源的持久化框架，用于将Java对象映射到关系数据库中。它通过XML或注解的方式配置SQL语句和结果映射，提供了灵活和强大的数据库访问功能。MyBatis提供了SQL的完全控制权限，同时也提供了许多便利的特性，使得数据库操作更加简单和高效。它被广泛应用于Java web开发和企业级应用中，是一个非常受欢迎的框架之一。

1.入门

1.创建一个maven工程 pom文件中导包

  org.mybatis
  mybatis
  x.x.x


      mysql
      mysql-connector-java
      8.0.33
    
    
      org.projectlombok
      lombok
      1.18.28


2.创建一个resources文件夹 并make
	创建一个 mybatis-config.xml文件
	
	




    
    
        
        
            
            
            
            
                
                
                
                
            
        
    

    
        
    



3.在文件夹下创建一个mapper文件夹并创建StudentMapper.xml文件





    

2.使用mybatis实现增删改查

StudentMapper.xml

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.aaa.mapper.StudentMapper">

    <insert id="saveStudent">
        insert into student
        values (null, '新数据', 18, '郑州', 1)
    insert>

    <delete id="delStudent">
        delete
        from student
        where id = 2
    delete>

    <update id="updateStudent">
        update student
        set sname = '张三'
        where id = 1
    update>

    <select id="listStudent" resultType="com.aaa.dto.Student">
        select *
        from student
    select>

mapper>

JavaTest

package com.aaa.test;

import com.aaa.dto.Student;
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;

/**
 * @Author Grg
 * @Date 2023/9/12 9:01
 * @PackageName:com.aaa.test
 * @ClassName: JavaTest
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public class JavaTest {
    @Test
    public void test() throws IOException {
        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        int i = sqlSession.insert("com.aaa.mapper.StudentMapper.saveStudent");
        System.out.println(i);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();

    }

    @Test
    public void test1() throws IOException {
        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        int i = sqlSession.delete("com.aaa.mapper.StudentMapper.delStudent");
        System.out.println(i);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();
    }
    @Test
    public void test2() throws IOException {
        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        int i = sqlSession.update("com.aaa.mapper.StudentMapper.updateStudent");
        System.out.println(i);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void test3() throws IOException {
        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        List<Student> data = sqlSession.selectList("com.aaa.mapper.StudentMapper.listStudent");
        System.out.println(data);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();
    }
}

3.sql语句传参CRUD

创建学生实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Student implements Serializable {
    private Integer id;
    private String sname;
    private String sage;
    private String saddress;
    private Integer sgid;
}

StudentMapper.xml

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.aaa.mapper.StudentMapper">

    <insert id="saveStudent" parameterType="com.aaa.entity.Student">
        insert into student
        values (null, #{name}, #{age}, #{address}, 1)
    insert>

    <delete id="delStudent" parameterType="java.lang.Integer">
        delete
        from student
        where id = #{id}
    delete>

    <update id="updateStudent" parameterType="com.aaa.entity.Student">
        update student
        set name=#{name},
            age=#{age},
            address=#{address},
            gid=#{gid}
        where id = #{id}
    update>

    <select id="getOne" parameterType="java.lang.Integer" resultType="com.aaa.entity.Student">
        select *
        from student
        where id = #{id}
    select>

    <select id="listStudent" resultType="com.aaa.entity.Student">
        select *
        from student
    select>

mapper>

JavaTest

package com.aaa.test;

import com.aaa.entity.Student;
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;

/**
 * @Author Grg
 * @Date 2023/9/12 9:01
 * @PackageName:com.aaa.test
 * @ClassName: JavaTest
 * @Description: 又是码代码的一天
 * @Version plus max 宇宙无敌终极版本
 */
public class JavaTest {
    @Test
    public void test() throws IOException {
        Student student = new Student(null, "haha", 18, "dddd", 1);

        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        int i = sqlSession.insert("com.aaa.mapper.StudentMapper.saveStudent",student);
        System.out.println(i);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();

    }

    @Test
    public void test1() throws IOException {
        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        int i = sqlSession.delete("com.aaa.mapper.StudentMapper.delStudent",3);
        System.out.println(i);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void test2() throws IOException {
        Student student = new Student(5, "qweqwrqwreq", 19, "beijing", 3);

        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
        SqlSession sqlSession = sqlSessionFactory.openSession();

        int i = sqlSession.update("com.aaa.mapper.StudentMapper.updateStudent",student);
        System.out.println(i);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();
    }

    @Test
    public void test3() throws IOException {
        //读取配置文件
        String resource = "mybatis-config.xml";
        // 获取资源输入流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        // 创建会话工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        // 通过工厂获取SqlSession 相当于拿到一个连接对象 进行数据库操作
          SqlSession sqlSession = sqlSessionFactory.openSession();
//        Student s = sqlSession.selectOne("com.aaa.mapper.StudentMapper.getOne",1);
//        System.out.println(s);
        List<Student> data = sqlSession.selectList("com.aaa.mapper.StudentMapper.listStudent");
        System.out.println(data);

        //mybatis自带的实务操作
        sqlSession.commit();
        sqlSession.close();
    }
}