mybatis入门——mybatis使用实例

mybatis区别于其他ORM工具的地方是，他不需要dao成实现类，只提供接口，数据库操作的方法写到配置文件中。
贴个例子来理解下：
测试项目结构：

mybatis-config.xml:

<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<environments default="yitu">
<environment id="yitu">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/yitu"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<!-- 
 配置映射文件
 -->
<mappers>
<mapper resource="com/etoak/dao/CityDaoIf-mapper.xml"/>
</mappers>
</configuration>

CityDaoIf-mapper.xml

<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 
 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 
<mapper namespace="com.etoak.dao.CityDaoIf" >
<insert id="addCity" parameterType="com.etoak.bean.City">
        insert into city values(null,#{pid},#{name});
</insert>
<delete id="delCityById" parameterType="java.lang.Integer">
        delete from city where id=#{id};
</delete>
<update id="updateCity" parameterType="com.etoak.bean.City">
        update city set pid=#{pid},name=#{name} where id=#{id};
</update>
<!-- 
 resultMap： 返回数据类型 
 需要在下文中解释
 -->
<select id="selectCityById" parameterType="java.lang.Integer" resultMap="city">
        select * from city where id=#{id};
</select>
<!-- 
 这里返回的是list，但list里面存放的还是city对象，所以还是city
 -->
<select id="selectAllCitys" resultMap="city">
        select * from city;
</select>
<select id="selectCityCount" resultType="java.lang.Integer">
        select count(*) from city;
</select>
<select id="selectCityByPage" parameterType="java.util.Map" resultMap="city">
        select * from city limit #{start},#{max};
</select>   


<!-- 
 返回类型解释
 -->
<resultMap type="com.etoak.bean.City" id="city">
<result property="id" column="id"/>
<result property="pid" column="pid"/>
<result property="name" column="name"/>
</resultMap>
</mapper>

CityDaoIf.java

package com.etoak.dao;

import java.util.List;
import java.util.Map;

import com.etoak.bean.City;

public interface CityDaoIf {
/**
 * 使用mybatis时需注意：
 * 1 添加、删除、修改 返回值为 int类型 
 * 影响的行数 ==1 判断是否成功
 * 2 如果方法涉及到传入的参数量多余一条；需要封装成map
 */
public int addCity(City city);
public int delCityById(Integer id);
public int updateCity(City city);
public City selectCityById(Integer id);
public List<City> selectAllCitys();
public int selectCityCount();
// map: start end
public List<City> selectCityByPage(Map map);
}

MybatisFactory.java

package com.etoak.factory;

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

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

public class MybatisFactory {   
private static SqlSessionFactory factory;
static{
try {
            Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
            factory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
public static SqlSessionFactory getSqlSessionFactory(){
return factory;
    }
}

实体类City.java

package com.etoak.bean;


public class City implements java.io.Serializable {



private Integer id;
private Integer pid;
private String name;


public City() {
    }

public City(Integer pid, String name) {
this.pid = pid;
this.name = name;
    }

public Integer getId() {
return this.id;
    }

public void setId(Integer id) {
this.id = id;
    }

public Integer getPid() {
return this.pid;
    }

public void setPid(Integer pid) {
this.pid = pid;
    }

public String getName() {
return this.name;
    }

public void setName(String name) {
this.name = name;
    }

}

测试类：

package com.etoak.test;

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

import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import com.etoak.bean.City;
import com.etoak.dao.CityDaoIf;
import com.etoak.factory.MybatisFactory;

public class Test {
public static void main(String[] args){
        SqlSessionFactory factory = MybatisFactory.getSqlSessionFactory();
        SqlSession session = factory.openSession();
        CityDaoIf dao = session.getMapper(CityDaoIf.class);
int add = dao.addCity(new City(55,"e"));
int del = dao.delCityById(4);
        City c = new City();
        c.setId(3);
        c.setPid(1);
        c.setName("aaaa");
int update = dao.updateCity(c);
        City city = dao.selectCityById(3);
        Map map = new HashMap();
        map.put("start", 1);
        map.put("max", 5);
//List list = dao.selectCityByPage(new Map());

//System.out.println("add="+add+"del="+del+"update="+update);
        System.out.println(dao.selectCityByPage(map));
        session.commit();
        session.close();

    }
}