增删改查

Posted 2020-10-20 Dong诗原

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1、项目结构

2、主要代码

　　①EmployeeMapper.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">
<!-- 
namespace:名称空间;  指定接口全类名
id:唯一标识
resultType：返回值类型
#{id}：从传递过来的参数中取出id值 

public Employee getEmpById();
-->
  <select id="getEmpById" resultType="com.atguigu.mybatis.bean.Employee">
    select id,last_name lastName,email,gender from tbl_employee where id = #{id}
  </select>
  
    <!-- public void addEmp(Employee employee) ;
            parameterType:传入参数类型，可以省略
            resultType：接收参数类型
     -->
    
    <insert id="addEmp" parameterType="com.atguigu.mybatis.bean.Employee">
        insert into tbl_employee(last_name,email,gender) 
            values(#{lastName},#{email},#{gender})
    </insert>
    
    <!-- public void updateEmp(Employee employee) ; -->
    <update id="updateEmp">
        update tbl_employee 
            set last_name=#{lastName},email=#{email},gender=#{gender} 
                where id=#{id}
    </update>
    
    <!-- public void deleteEmpById(Integer id) ; -->
      <delete id="deleteEmpById">
          delete from tbl_employee where id=#{id}
      </delete>
  
  
</mapper>

parameterType:传入参数类型，可以省略
resultType：接收参数类型，可以省略
　　②MybatisTest.java

package com.atguigu.mybatis.test;

import java.io.IOException;
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.bean.Employee;
import com.atguigu.mybatis.dao.EmployeeMapper;
import com.atguigu.mybatis.dao.EmployeeMapperAnnotation;

public class MybatisTest {
    
    private SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(inputStream);
    }
    /*
     * 1、Mybatis允许增删改查直接定义以下类型返回值
     *         integer、Long、Boolean、void
     * 2、手动提交数据
     * 
    */
    @Test
    public void test04() throws IOException {
        SqlSessionFactory sqlSessionFactory =getSqlSessionFactory();
        //1、获取到的SqlSession不会自动提交
        SqlSession openSession= sqlSessionFactory.openSession();
        try {
            /*2.获取接口的实现对象*/
            EmployeeMapper mapper= openSession.getMapper(EmployeeMapper.class);
            //mapper为代理对象，执行增删改查
            Employee employee=new Employee(2, "jerry", "jerry@atguigu.com", "0");
            //添加信息
            /*mapper.addEmp(employee);*/
            //更新信息
            /*mapper.updateEmp(employee);*/
            //删除信息
            mapper.deleteEmpById(3);
            //3、手动提交
            openSession.commit();
            
        } finally {
            openSession.close();
        }
        
    }
}