利用MyBatis实现对数据库操作的流程

1. 连接到数据库

<!--环境配置，连接的数据库，这里使用的是MySQL-->
<environments default="mysql">
    <environment id="mysql">
        <!--指定事务管理的类型，这里简单使用Java的JDBC的提交和回滚设置-->
        <transactionManager type="JDBC"></transactionManager>
        <!--dataSource 指连接源配置，POOLED是JDBC连接对象的数据源连接池的实现-->
        <dataSource type="POOLED">
            <property name="driver" value="com.mysql.cj.jdbc.Driver"></property>
            <property name="url" value="jdbc:mysql://127.0.0.1:3306/books?serverTimezone=GMT%2B8"></property>
            <property name="username" value="winds"></property>
            <property name="password" value="winds970118"></property>
        </dataSource>
    </environment>
</environments>

2.实体类

package com.zzy.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Book {
    private int id;
    private String name;
    private String auth;

}

3. 接口的设置

package com.zzy.repository;

import com.zzy.entity.Book;

import java.util.List;

public interface BookRepository {
    public int add(Book book);
    public List<Book> findAll();
    public int delete(int id);
}

4.配置Mapper文件

<?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.zzy.repository.BookRepository">
    <insert id="add" parameterType="com.zzy.entity.Book">
        insert into book(id,name,auth) values (#{id},#{name},#{auth})
    </insert>
    <select id="findAll" resultType="com.zzy.entity.Book">
        select * from book;
    </select>
    <delete id="delete" parameterType="int">
        delete from book where id = #{id}
    </delete>

</mapper>

5. 在Config.xml中设置Mapper文件的路径

<mappers>
    <!--这是告诉Mybatis区哪找持久化类的映射文件，对于在src下的文件直接写文件名，
        如果在某包下，则要写明路径,如：com/mybatistest/config/User.xml-->
    <mapper resource="com/zzy/mapper/BookMapper.xml"></mapper>
    <mapper resource="com/zzy/repository/Mapper.xml"></mapper>
</mappers>

6. 使用Mapper代理实现自定义接口

@Test
    //Mapper代理实现自定义接口
    public void test2(){
        InputStream inputStream = MyBatisTest.class.getClassLoader().getResourceAsStream("config.xml");
        SqlSessionFactoryBuilder sqlSessionFactoryBuilder = new SqlSessionFactoryBuilder();
        SqlSessionFactory sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        BookRepository  bookRepository = sqlSession.getMapper(BookRepository.class);
        //添加操作
//        Book book = new Book(11,"《骆驼祥子》","老舍");
//        System.out.println(bookRepository.add(book));
        //只要对数据库有修改，都要执行commit操作，数据库才能最终被修改
//        sqlSession.commit();
//        List<Book> res = bookRepository.findAll();
//        for(int i = 0 ;i < res.size();i++){
//            System.out.print(res);
//        }
        //对数据库的删除操作
        bookRepository.delete(10);
        sqlSession.commit();
       
       sqlSession.close();