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
数据库sql语句
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
sql映射文件
goodsMapper.xml
mybatis为我们提供了SqlSessionFactory接口，用来创建SqlSession，一个用来获得
SqlSession的类
dao类
dao实现类
测试类
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);
}
}