mybatis開發(fā)原始dao層請(qǐng)閱讀我的上一篇博客：mybatis開發(fā)dao層的兩種方式（原始dao層開發(fā)）
接上一篇博客繼續(xù)介紹mybatis開發(fā)dao層的第二種方式：mapper動(dòng)態(tài)代理方式
mapper接口開發(fā)方法只需要程序員編寫mapper接口（相當(dāng)于dao接口），由mybatis框架根據(jù)接口定義創(chuàng)建接口的動(dòng)態(tài)代理對(duì)象，代理對(duì)象的方法體同上一篇博客中dao接口實(shí)現(xiàn)類方法。
mapper接口開發(fā)需要遵循以下規(guī)范：
（1）mapper.xml文件中的namespace與mapper接口的類路徑相同。
（2）mapper接口方法名和mapper.xml中定義的每個(gè)statement的id相同
（3）mapper接口方法的輸入?yún)?shù)類型和mapper.xml中定義的每個(gè)sql 的parametertype的類型相同
（4）mapper接口方法的輸出參數(shù)類型和mapper.xml中定義的每個(gè)sql的resulttype的類型相同
1、定義mapper映射文件usermapper.xml（內(nèi)容同user.xml），需要修改namespace的值為 usermapper接口路徑。將usermapper.xml放在classpath 下sqlmapperr目錄下。
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<?xml version="1.0" encoding="utf-8" ?><!doctype mapperpublic "-//mybatis.org//dtd mapper 3.0//en""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.xyfer.mapper.usermapper"> <!-- 根據(jù)id查詢用戶 --> <select id="getuserbyid" parametertype="int" resulttype="com.xyfer.po.user"> select * from user where id = #{id} </select> <!-- 添加用戶 --> <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> <!-- 修改用戶 --> <update id="updateuser" parametertype="com.xyfer.po.user"> update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id} </update> <!-- 刪除用戶 --> <delete id="deleteuserbyid" parametertype="int"> delete from user where id=#{id} </delete> </mapper> |
2、usermapper.java接口文件
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package com.xyfer.mapper;import com.xyfer.po.user;public interface usermapper { public user getuserbyid(int id); //根據(jù)id值查詢一個(gè)用戶 public void insertuser(user user); //新增一個(gè)用戶 public void updateuser(user user); //修改一個(gè)用戶 public void deleteuser(int id); //刪除一個(gè)用戶} |
接口定義有如下特點(diǎn)：
（1）usermapper接口方法名和mapper.xml中定義的statement的id相同
（2）usermapper接口方法的輸入?yún)?shù)類型和mapper.xml中定義的statement的parametertype的類型相同
（3） usermapper接口方法的輸出參數(shù)類型和mapper.xml中定義的statement的resulttype的類型相同
3、在sqlmapconfig.xml文件中加載usermapper.xml文件
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<mappers> <mapper resource="usermapper.xml"/></mappers> |
4、測(cè)試
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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() { //獲取sqlsession sqlsession sqlsession = sqlsessionfactory.opensession(); //獲取usermapper接口代理對(duì)象 usermapper usermapper = sqlsession.getmapper(usermapper.class); //調(diào)用代理對(duì)象方法 user user = usermapper.getuserbyid(10); //打印結(jié)果 system.out.println(user); //關(guān)閉sqlsession sqlsession.close(); } @test public void testinsertuser() { //獲取sqlsession sqlsession sqlsession = sqlsessionfactory.opensession(); //獲取usermapper接口代理對(duì)象 usermapper usermapper = sqlsession.getmapper(usermapper.class); //新建一個(gè)對(duì)象 user user = new user(); user.setusername("小謝"); user.setsex("男"); user.setbirthday(new date()); user.setaddress("浙江省杭州市"); //調(diào)用代理對(duì)象方法 usermapper.insertuser(user); //關(guān)閉sqlsession sqlsession.close(); } @test public void testupdateuser() { //獲取sqlsession sqlsession sqlsession = sqlsessionfactory.opensession(); //獲取usermapper接口代理對(duì)象 usermapper usermapper = sqlsession.getmapper(usermapper.class); //新建一個(gè)對(duì)象 user user = new user(); user.setusername("小謝"); user.setsex("男"); user.setbirthday(new date()); user.setaddress("上海市"); //調(diào)用代理對(duì)象方法 usermapper.updateuser(user); //關(guān)閉sqlsession sqlsession.close(); } @test public void testdeleteuser() { //獲取sqlsession sqlsession sqlsession = sqlsessionfactory.opensession(); //獲取usermapper接口代理對(duì)象 usermapper usermapper = sqlsession.getmapper(usermapper.class); //調(diào)用代理對(duì)象方法 usermapper.deleteuser(6); //關(guān)閉sqlsession sqlsession.close(); }} |
以上步驟，完成mybatis框架以mapper動(dòng)態(tài)代理方式開發(fā)dao層，并對(duì)數(shù)據(jù)庫進(jìn)行增刪改查操作。
需要注意的是，上文提到的config文件夾和sqlmapper文件夾均為資源文件夾（source folder），默認(rèn)會(huì)加載該路徑下的文件。希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：http://www.cnblogs.com/xyfer1018/p/10117227.html
