Day9——使用MyBatis实现基本的CRUD操作

悠悠 2023-07-04 11:28 5阅读 0赞

# 一. 知识储备 #

增删改查分别在SQL映射文件使用`<insert>`、`<delete>`、`<update>`、`<select>`标签

### [前往免费下载源码][Link 1] ###

# 二. 例子 #

EmployeeMapper.java

package com.atguigu.mybatis.dao;
    
    import com.atguigu.mybatis.beans.Employee;
    
    public interface EmployeeMapper { 
    
    	public Employee selectEmployeeById(Integer id);
    	
        public void insertEmployee(Employee employee);
        
        public void updateEmployee(Employee employee);
        
        public void deleteEmployeeById(Integer id);
    	
    }

EmployeeMapper.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="com.atguigu.mybatis.dao.EmployeeMapper">
    	
    	<select id="selectBlog" resultType="com.atguigu.mybatis.beans.Employee"> 
    	  select id, last_name lastName, email, gender from tbl_employee where id = #{id}  
    	</select>
    	
    	
    	<select id="selectEmployeeById" resultType="com.atguigu.mybatis.beans.Employee">
    	    select id, last_name, email, gender from tbl_employee where id = #{id}
    	</select>
    	
    	
    	 
    	 <insert id="insertEmployee" parameterType="com.atguigu.mybatis.beans.Employee">
    	     insert into tbl_employee (last_name, email, gender) values (#{lastName}, #{email}, #{gender})
    	 </insert>
    	
    	
    	
    	<update id="updateEmployee">
    	     update tbl_employee set
    	        last_name = #{lastName},
    	        email = #{email},
    	        gender = #{gender}
    	     where id = #{id}
    	</update>
    	
    	
    	
    	<delete id="deleteEmployeeById">
    	    delete from tbl_employee where id = #{id}
    	</delete>
    	
    </mapper>

TestMyBatis.java

package com.atguigu.mybatis.test;
    
    import java.io.InputStream;
    
    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 com.atguigu.mybatis.beans.Employee;
    import com.atguigu.mybatis.dao.EmployeeMapper;
    
    public class TestMyBatis { 
    
    	@Test
    	public void testCRUD() throws Exception{ 
    		String resource = "mybatis-config.xml"; 
    		InputStream inputStream = 
    				Resources.getResourceAsStream(resource); 
    		SqlSessionFactory sqlSessionFactory = 
    				new SqlSessionFactoryBuilder().build(inputStream);
    		
    		SqlSession session = sqlSessionFactory.openSession(); 
    		
    		try { 
    			EmployeeMapper mapper = session.getMapper(EmployeeMapper.class);
    			
    			//1. 插入
    // Employee employee = new Employee(null, "婷姐", "tj@atguigu.com", "0");
    // mapper.insertEmployee(employee);
    			
    			//2. 修改
    // Employee employee = new Employee(1003, "婷婷", "tt@sina.com", "0");
    // mapper.updateEmployee(employee);
    			
    			//3.删除
    			mapper.deleteEmployeeById(1003);
    			
    			//增删改操作需要提交
    			session.commit();
    			
    		} finally { 
    			// TODO: handle finally clause
    			session.close();
    		}
    		
    	}
    	
    }

[Link 1]: https://me.csdn.net/download/qq_40634846