Mybatis 注解配置和接口方式增删改查-SQL语句写入到接口类中

本文介绍了一个使用 MyBatis 框架实现增删改查（CRUD）操作的 Java 示例项目，包括接口定义、XML 映射文件配置及测试用例。

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1、接口类代码

package javastudy;

import java.util.List;

import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;

public interface UserMapper {
	@Select("select * from user where id = #{id}")
	public User selectUser(int id);
	@Select(" select * from user")
	public List<User> selectAll();
	@Insert("insert into user (userName,userPwd) values (#{userName},#{userPwd})")
	public void addUser(User user);
	@Update("update user set userName=#{userName},userPwd=#{userPwd} where id=#{id}")
	public void updateUser(User user);
	@Delete("delete from user where id=#{id}")
	public void deleteUser(int id);

}

2、修改userMapper.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="javastudy.UserMapper">
 
</mapper>

说明：这里的配置不能与注解方式冲突，一般全部SQL写在XML或接口类中，当然也可以把一部分SQL写在XML，一部分写在接口类中，但是同一个SQL不能两个地方同时写。

3、mybtis-config.xml文件不用变

4、测试类代码

package test;

import java.io.IOException;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import javastudy.User;
import javastudy.UserMapper;
import utility.MyBatisUtils;
public class MyTest {
	@Test
	public void testSelect() throws IOException {
		SqlSession session=MyBatisUtils.openSession();
		UserMapper userMapper=session.getMapper(UserMapper.class);
		User user=userMapper.selectUser(1);
		System.out.println(user);
		session.close();
	}
	@Test
	public void testSelectAll() throws IOException {
		SqlSession session=MyBatisUtils.openSession();
		UserMapper userMapper=session.getMapper(UserMapper.class);
		List<User> list=userMapper.selectAll();
		System.out.println(list);
		session.close();
	}
	@Test
	public void testInsert() throws IOException {
		SqlSession session=MyBatisUtils.openSession();
		UserMapper userMapper=session.getMapper(UserMapper.class);
		User user=new User();
		user.setUserName("tangbin");
		user.setUserPwd("168888");
		userMapper.addUser(user);
		session.commit();
		session.close();
	}
	@Test
	public void testUpdate() throws IOException {
		SqlSession session=MyBatisUtils.openSession();
		UserMapper userMapper=session.getMapper(UserMapper.class);
		User user=new User();
		user.setId(5);
		user.setUserName("王五");
		user.setUserPwd("wangwu123456");
		userMapper.updateUser(user);
		session.commit();
		session.close();
	}
	@Test
	public void testDelete() throws IOException {
		SqlSession session=MyBatisUtils.openSession();
		UserMapper userMapper=session.getMapper(UserMapper.class);
		userMapper.deleteUser(4);
		session.commit();
		session.close();
	}
	
}