MyBatis编写映射文件实现增删改操作 附说明及代码

1.看一下我们接口

package cn.bdqn.mybatis.dao;

import org.apache.ibatis.annotations.Select;

import cn.bdqn.mybatis.been.Emp;
/**
 * 这个接口不用写实现类,是用来给empMapper.xml进行动态绑定的
 * @author Administrator
 *
 */
public interface EmpMapper {

	public Emp getEmpById(Integer id);
	public void addEmp(Emp emp);
	/**
	 * MyBatis允许增删改直接定义一下类型返回值
	 * int long boolean 以及相应的包装类,
	 * 在接口中定义方法的时候,直接定义相应的返回值即可,无其他操作
	 * @param emp
	 * @return
	 */
	public boolean updateEmp(Emp emp);
	public void deleteEmpById(Integer id);
}

　　

2.编写mapper

<?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">
<!--namespace:名称空间 -->
<mapper namespace="cn.bdqn.mybatis.dao.EmpMapper">
	<!-- id,唯一标识 resultType:返回值类型,bean的全限定名称 #{id},从传递过来的参数中取出id值,相当于换位符 public
		Emp getEmpById(Integer id); -->
	<select id="getEmpById" resultType="cn.bdqn.mybatis.been.Emp"
		databaseId="mysql">
		select * from emp where id = #{id}
	</select>
	<select id="getEmpById" resultType="cn.bdqn.mybatis.been.Emp"
		databaseId="oracle">
		select * from emp where id = #{id}
	</select>
	<!-- public void addEmp(Emp emp); insert标签: id:对应我们javaBean的方法名 parameterType
		可以省略,如果要写就是javaBean的全限定名称 insert into emp(last_name,gender,email) values(#{last_name},#{gender},#{email})
		结尾不需要分号,values值的#{对应的javaBean的属性名} -->
	<insert id="addEmp" parameterType="cn.bdqn.mybatis.been.Emp">
		insert into emp(last_name,email,gender)
		values(#{last_name},#{email},#{gender})
	</insert>
	<!-- update标签: public void updateEmp(Emp emp); id:对应我们javaBean的方法名 parameterType
		可以省略,如果要写就是javaBean的全限定名称 update emp set last_name=#{last_name},email=#{email},gender=#{gender}
		while id=#{id} 结尾不需要分号,#{}相当于占位符,等于我们传过来的值 -->
	<update id="updateEmp">
		update emp set last_name=#{last_name},email=#{email},gender=#{gender}	where
		id=#{id}
	</update>
	<!-- delet标签: public void deleteEmpById(Integer id); -->
	<delete id="deleteEmpById">
		delete from emp where id=#{id}
	</delete>

</mapper>

　　3.编写测试类

package cn.bdqn.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 cn.bdqn.mybatis.been.Emp;
import cn.bdqn.mybatis.dao.EmpMapper;

public class MyBatisTest_02 {
	public static void main(String[] args) throws IOException {
		//获取SqlSessionFactory实例
		String resource="mybatis-config.xml";
		InputStream is = Resources.getResourceAsStream(resource);
		 SqlSessionFactory build = new SqlSessionFactoryBuilder().build(is);
		 //获取到的sqlsession不会自动提交
		 SqlSession openSession = build.openSession();
		 try{
			 //测试添加
			 EmpMapper mapper = openSession.getMapper(EmpMapper.class);
		 /*	 Emp emp = new Emp(null,"liyuanfeng","liyuanfeng@qq.com","1");
			 mapper.addEmp(emp);*/
			 //测试修改
			 Emp emp = new Emp(1,"liyuanfeng","liyuanfeng@qq.com","1");
			 mapper.updateEmp(emp);

			 //进行手动提交
			 openSession.commit();
		 }finally{
			 openSession.close();
		 }

	}

}