详解MyBatis开发Dao层的两种方式（Mapper动态代理方式）

<?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.xyfer.mapper.usermapper" >

   <!-- 根据id查询用户 -->

   <select id= "getuserbyid" parametertype= "int" resulttype= "com.xyfer.po.user" >

     select * from user where id = #{id}

   </select>

   <!-- 添加用户 -->

   <insert id= "insertuser" parametertype= "com.xyfer.po.user" >

   <selectkey keyproperty= "id" order= "after" resulttype= "java.lang.integer" >

     select last_insert_id()

   </selectkey>

    insert into user(username,birthday,sex,address)

    values(#{username},#{birthday},#{sex},#{address})

   </insert>

   <!-- 修改用户 -->

   <update id= "updateuser" parametertype= "com.xyfer.po.user" >

     update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address}

     where id=#{id}

   </update>

   <!-- 删除用户 -->

   <delete id= "deleteuserbyid" parametertype= "int" >

     delete from user where id=#{id}

   </delete>

  </mapper>

package com.xyfer.mapper;

import com.xyfer.po.user;

public interface usermapper {

   public user getuserbyid( int id);  //根据id值查询一个用户

   public void insertuser(user user); //新增一个用户

   public void updateuser(user user); //修改一个用户

   public void deleteuser( int id);  //删除一个用户

}

<mappers>

   <mapper resource= "usermapper.xml" />

</mappers>

package com.xyfer.mapper;

import static org.junit. assert .*;

import java.io.inputstream;

import java.util.date;

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.before;

import org.junit.test;

import com.xyfer.po.user;

import junit.framework.testcase;

public class usermappertest extends testcase{

   private sqlsessionfactory sqlsessionfactory;

   protected void setup() throws exception {

     sqlsessionfactorybuilder sessionfactorybuilder = new sqlsessionfactorybuilder();

     inputstream inputstream = resources.getresourceasstream( "sqlmapconfig.xml" );

     sqlsessionfactory = sessionfactorybuilder.build(inputstream);

   }

   @test

   public void testgetuserbyid() {

     //获取sqlsession

     sqlsession sqlsession = sqlsessionfactory.opensession();

     //获取usermapper接口代理对象

     usermapper usermapper = sqlsession.getmapper(usermapper. class );

     //调用代理对象方法

     user user = usermapper.getuserbyid( 10 );

     //打印结果

     system.out.println(user);

     //关闭sqlsession

     sqlsession.close();

   }

   @test

   public void testinsertuser() {

     //获取sqlsession

     sqlsession sqlsession = sqlsessionfactory.opensession();

     //获取usermapper接口代理对象

     usermapper usermapper = sqlsession.getmapper(usermapper. class );

     //新建一个对象

     user user = new user();

     user.setusername( "小谢" );

     user.setsex( "男" );

     user.setbirthday( new date());

     user.setaddress( "浙江省杭州市" );

     //调用代理对象方法

     usermapper.insertuser(user);

     //关闭sqlsession

     sqlsession.close();

   }

   @test

   public void testupdateuser() {

     //获取sqlsession

     sqlsession sqlsession = sqlsessionfactory.opensession();

     //获取usermapper接口代理对象

     usermapper usermapper = sqlsession.getmapper(usermapper. class );

     //新建一个对象

     user user = new user();

     user.setusername( "小谢" );

     user.setsex( "男" );

     user.setbirthday( new date());

     user.setaddress( "上海市" );

     //调用代理对象方法

     usermapper.updateuser(user);

     //关闭sqlsession

     sqlsession.close();

   }

   @test

   public void testdeleteuser() {

     //获取sqlsession

     sqlsession sqlsession = sqlsessionfactory.opensession();

     //获取usermapper接口代理对象

     usermapper usermapper = sqlsession.getmapper(usermapper. class );

     //调用代理对象方法

     usermapper.deleteuser( 6 );

     //关闭sqlsession

     sqlsession.close();

   }

}