mybatis入门例子

mybatis是由ibatis发展而来的，是一个很好用的javaee持久化框架，很容易学，下面是一个增删改查的小例子

简单的pojo类

 package com.own.entity;

public class Goods {
  
	public int getGoodsId() {
		return goodsId;
	}
	public void setGoodsId(int goodsId) {
		this.goodsId = goodsId;
	}
	public String getGoodName() {
		return goodName;
	}
	public void setGoodName(String goodName) {
		this.goodName = goodName;
	}
	public double getPrice() {
		return price;
	}
	public void setPrice(double price) {
		this.price = price;
	}
	private int goodsId;
	private String goodName;
	private double price;
	
}

  

数据库sql语句

  /*
Navicat MySQL Data Transfer

Source Server         : mysql
Source Server Version : 50165
Source Host           : localhost:3306
Source Database       : testdb

Target Server Type    : MYSQL
Target Server Version : 50165
File Encoding         : 65001

Date: 2012-09-11 12:46:12
*/

SET FOREIGN_KEY_CHECKS=0;

-- ----------------------------
-- Table structure for `goods`
-- ----------------------------
DROP TABLE IF EXISTS `goods`;
CREATE TABLE `goods` (
  `goodsId` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `price` double(10,2) NOT NULL,
  `goodName` varchar(20) NOT NULL,
  PRIMARY KEY (`goodsId`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of goods
-- ----------------------------
INSERT INTO `goods` VALUES ('1', '1.54', '冰激凌');
INSERT INTO `goods` VALUES ('2', '3.60', '面包');
INSERT INTO `goods` VALUES ('7', '5200.00', 'thinkpad笔记本');
INSERT INTO `goods` VALUES ('8', '5200.00', 'thinkpad笔记本');

和hibernate一样，它也需要一个全局配置文件,用于指定程序正常运行所需的设置和参数信息。它也需要一个数据库表和javabean的映射信息文件，称之为映射文件

全局配置文件 configuration.xml

   <?xml version="1.0" encoding="UTF-8"?>  
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">  
<configuration>     
   
   <!--为java类指定别名，可以再xml文件中用别名取代java类的全限定名 -->
    <typeAliases>  
        <typeAlias alias="Goods" type="com.own.entity.Goods"/>  
    </typeAliases>  
      
    <environments default="development">  
        <environment id="development">  
            <transactionManager type="JDBC"/>  
            <dataSource type="POOLED">  
                <property name="driver" value="com.mysql.jdbc.Driver"/>  
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/testdb"/>  
                <property name="username" value="root"/>  
                <property name="password" value="zyp"/>  
            </dataSource>  
        </environment>  
    </environments>  
    
    <!-- 引入sql映射文件 -->  
    <mappers>  
        <mapper resource="com/own/entity/goodsMapper.xml"/>  
    </mappers>  
    
    
</configuration>  

sql映射文件

goodsMapper.xml

  <?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.own.GoodsMapper">   
    
    <!--  java 对象与数据库字段对应，如果数据库字段与java对象属性名称一样，可以不写 -->
    <resultMap type="Goods" id="goodsId">
     <result column="goodsId" property="goodsId" javaType="int" />
     <result column="goodName" property="goodName" javaType="string" />
     <result column="price" property="price" javaType="float" />
    </resultMap> 
    
    <!-- 查询语句，parameterType为sql语句参数的类型,resultType 为执行这个 语句的返回类型-->
   <select id="selectGoods" parameterType="int" resultType="Goods">    
       select goodsId,goodName from goods where goodsId = #{goodsId}
    </select>
     
    <insert id="insertGoods" parameterType="Goods" useGeneratedKeys="true" keyProperty="goodsId"  keyColumn="goodsId"  >
      insert into goods(goodName,price) values(#{goodName},#{price})
    </insert>
    
    <delete id="deleteGoods" parameterType="int"  >
     delete from goods where goodsId=#{goodsId}
    </delete>
    <!-- 传递多个参数，使用javaBean 这里要注意参数的名字(也就是#{}里面的参数)一定要和javaBean属性名字一样，否则会抛出异常（mybatis要调用getxxx给参数赋值）  -->
    <update id="updateGoods" parameterType="Goods"  >
        update goods set price=#{price} where goodsId=#{goodsId}
    </update>
    <!-- 使用map传递多个参数   参数名称为的key -->
    <update id="updateGoodsByMapParam" parameterType="map" >
      update goods set price=#{price} where goodsId=#{id};
    </update>
</mapper> 
  

mybatis为我们提供了SqlSessionFactory接口，用来创建SqlSession，一个用来获得
SqlSession的类

   package com.own.util;

import java.io.IOException;
import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MybatisHelper {
  
	private static SqlSessionFactory sqlSessionFactory;
	
	static{
		
		String resourceLocation = "mybatis-config.xml";

		Reader reader = null;
		try {
			//Resources  mybatis 用来加载各种配置文件，这里我们从类路径加载
			reader = Resources.getResourceAsReader(resourceLocation);
			sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	  
		
		
	}
	
	public static SqlSession getSqlSession(){
		return sqlSessionFactory.openSession();
	}
	
	
	
}

dao类

  package com.own.dao;

import java.util.Map;

import com.own.entity.Goods;

public interface GoodsDao {
    /**
     *  根据id得到商品
     * @param id
     * @return
     */
	Goods getGoodsById(int id);
   /**
    * 存放商品
    * @param good
    * @return
    */
	int  saveGoods(Goods good);
	/**
	 * 删除id删除商品
	 * @param id
	 * @return
	 */
	int deleteGoodsById(int id);
	/*
	 * 更新一个商品
	 */
	int updateGoodsById(Goods good);
	
	/*
	 * 根据map参数更新对象
	 */
	int updateGoodsById(Map<String,Object> map);
	
}

dao实现类

  package com.own.dao.impl;

import java.util.Map;

import org.apache.ibatis.session.SqlSession;
import com.own.dao.GoodsDao;
import com.own.entity.Goods;
import com.own.util.MybatisHelper;

public class GoodsDaoImpl implements GoodsDao {

	
	@Override
	public Goods getGoodsById(int id) {
		// TODO Auto-generated method stub

		SqlSession sqlSession = MybatisHelper.getSqlSession();
		Goods goods = null;
		try {
			goods = sqlSession.selectOne("com.own.GoodsMapper.selectGoods",id);
			sqlSession.commit();
		}finally {
          sqlSession.close();
		}

		return goods;

	}

	@Override
	public int saveGoods(Goods good) {
		// TODO Auto-generated method stub
		SqlSession sqlSession = MybatisHelper.getSqlSession();
		int result = -1;
		
		try {
		   result =	sqlSession.insert("com.own.GoodsMapper.insertGoods",good);
		   sqlSession.commit();
		}finally {

			sqlSession.close();

		}
     return result;
	
	}

	@Override
	public int deleteGoodsById(int id) {
		// TODO Auto-generated method stub
		SqlSession sqlSession = MybatisHelper.getSqlSession();
		int result = -1;
		
		try {
		   result =	sqlSession.delete("com.own.GoodsMapper.deleteGoods",id);
		   sqlSession.commit();
		}finally {

			sqlSession.close();

		}
     return result;
	}

	@Override
	public int updateGoodsById(Goods goods) {
		// TODO Auto-generated method stub
	   
		SqlSession sqlSession = MybatisHelper.getSqlSession();
		int result = -1;
		
		try {
		   result =	sqlSession.update("com.own.GoodsMapper.updateGoods",goods);
		   sqlSession.commit();
		}finally {
			sqlSession.close();

		}
     return result;
		
		
	}

	@Override
	public int updateGoodsById(Map<String, Object> map) {
		// TODO Auto-generated method stub
		 
		SqlSession sqlSession = MybatisHelper.getSqlSession();
		int result = -1;
		
		try {
		   result =	sqlSession.update("com.own.GoodsMapper.updateGoodsByMapParam",map);
		   sqlSession.commit();
		}finally {
			sqlSession.close();

		}
     return result;
	}
	

}

测试类

  package com.own.dao.impl;

import static org.junit.Assert.*;

import java.util.HashMap;
import java.util.Map;

import org.junit.Before;
import org.junit.Test;

import com.own.dao.GoodsDao;
import com.own.entity.Goods;

public class GoodsDaoImplTest {
   
	private GoodsDao goodsDao = null;
	
	@Before
	public void setUp(){
		goodsDao = new GoodsDaoImpl();
	}
	
	
	@Test
	public void testGetGoodsById() {
		Goods goods = goodsDao.getGoodsById(2);
		System.out.print(goods.getPrice());
	}
   
	@Test
	public void testInsertGoods(){
		Goods goods = new Goods();
		goods.setGoodName("thinkpad笔记本");
		goods.setPrice(5200);
		int actual = goodsDao.saveGoods(goods);
		assertEquals(1,actual);
	}
	
	
	@Test
	public void testDeleteGoodsById(){
		int id = 1;
		int actual = goodsDao.deleteGoodsById(id);
	    assertEquals(1,actual);
	}
	
	@Test
	public void testUpdateGoodsById1(){
		Goods goods = new Goods();
		goods.setGoodsId(2);
		goods.setPrice(3250.20);
		Map<String,Object> map = new HashMap<String,Object>();
	    map.put("price",5521);
		map.put("id",2);
		int actual = goodsDao.updateGoodsById(map);
	   assertEquals(1,actual);
	}
	

	@Test
	public void testUpdateGoodsById(){
		Goods goods = new Goods();
		goods.setGoodsId(2);
		goods.setPrice(36.20);
	    int actual = goodsDao.updateGoodsById(goods);
	   assertEquals(1,actual);
	}
	
	

	
	
}