IDEA+mybatis实现增删改查(CURD)

原文链接：这里

0.前言

操作mybaits和mysql进行增删改查是必备的一步，今天写一篇文章简单记录一下mybatis的增删改查操作。

本文源代码放在github上。

1.具体操作

studnetsMapper文件

package com.cat.dao;

 

import com.cat.pojo.Students;

import java.util.List;

 

public interface StudentsMapper {

//所有学生

List<Students> listAllStudents();

 

//删除一名学生信息

int deleteStudent(int id);

 

//新增一名学生

int addStudent(Students students);

 

//修改一名学生信息

int updateStudentById(Students students);

 

 

}

StudentsMapper.xml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.cat.dao.StudentsMapper">

<!--展示所有学生-->

<select id="listAllStudents" resultType="com.cat.pojo.Students">

select * from students;

</select>

 

<!--删除一条学生信息-->

<delete id="deleteStudent" parameterType="int">

delete from students where id = #{id}

</delete>

 

<!--增加一名学生信息-->

<insert id="addStudent" parameterType="com.cat.pojo.Students">

insert into students(stu_name,stu_sex,class_id,age)

values (#{stu_name},#{stu_sex},#{class_id},#{age})

</insert>

<!--更新一名学生的信息-->

<update id="updateStudentById" parameterType="com.cat.pojo.Students">

update students set

stu_name= #{stu_name},

stu_sex= #{stu_sex},

class_id =#{class_id},

age=#{age}

where id =#{id}

</update>

</mapper>

Test文件

package com.cat.test;

import com.cat.dao.StudentsMapper;

import com.cat.pojo.Students;

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.HashMap;

import java.util.List;

import java.util.Map;

 

public class MyBatisTest {

 

//输出所有学生信息

@Test

public void test() throws IOException{

//获得核心配置文件

InputStream in = Resources.getResourceAsStream("MyBatisConfig.xml");

//获得session工厂对象

SqlSessionFactoryBuilder builder =new SqlSessionFactoryBuilder();

SqlSessionFactory factory=builder.build(in);

SqlSession session =factory.openSession();

//获得会话对象

List<Students> students =session.selectList("listAllStudents");

System.out.println(students);

session.close(); //关闭

}

 

//测试删除一名学生信息

@Test

public void deleteStudent() throws IOException{

//获得核心配置文件

InputStream in = Resources.getResourceAsStream("MyBatisConfig.xml");

//获得session工厂对象

SqlSessionFactoryBuilder builder =new SqlSessionFactoryBuilder();

SqlSessionFactory factory=builder.build(in);

SqlSession session =factory.openSession();

//获得会话对象

StudentsMapper studentsMapper = session.getMapper(StudentsMapper.class);

studentsMapper.deleteStudent(1000); //调用deleteStudent方法，删除id是1000的这个学生

session.close(); //关闭

}

 

//新增一名学生信息

@Test

public void addStudent() throws IOException{

//获得核心配置文件

InputStream in = Resources.getResourceAsStream("MyBatisConfig.xml");

//获得session工厂对象

SqlSessionFactoryBuilder builder =new SqlSessionFactoryBuilder();

SqlSessionFactory factory=builder.build(in);

SqlSession session =factory.openSession();

//获得会话对象

StudentsMapper studentsMapper = session.getMapper(StudentsMapper.class);

//构造一个新的学生

Students s =new Students();

 

s.setStu_name("呵呵");

s.setClass_id(1042);

s.setAge(16);

s.setStu_sex("男");

 

int res = studentsMapper.addStudent(s); //调用

 

session.commit(); //增删改必须提交事务

session.close(); //关闭

}

 

//修改一名学生信息

@Test

public void updateStudent() throws IOException{

//获得核心配置文件

InputStream in = Resources.getResourceAsStream("MyBatisConfig.xml");

//获得session工厂对象

SqlSessionFactoryBuilder builder =new SqlSessionFactoryBuilder();

SqlSessionFactory factory=builder.build(in);

SqlSession session =factory.openSession();

//获得会话对象

StudentsMapper studentsMapper = session.getMapper(StudentsMapper.class);

 

//把原来的学生信息修改

Students s= new Students();

s.setId(1001); //定向修改id是1001的学生

s.setStu_name("李十三"); //这个人的名字改成李十三

s.setStu_sex("男"); //性别改为男

s.setAge(24); //年龄修改为24

s.setClass_id(3002);

 

int res = studentsMapper.updateStudentById(s); //调用

session.commit(); //增删改必须提交事务

session.close(); //关闭

}

 

}