create database mybatisonetomany;

use mybatisonetomany;

CREATE TABLE user (

  id int(10) unsigned NOT NULL AUTO_INCREMENT,

  username varchar(64) NOT NULL DEFAULT '',

  mobile int(10) unsigned NOT NULL DEFAULT '0',

  created datetime NOT NULL DEFAULT '0000-00-00 00:00:00',

  PRIMARY KEY (id)

) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;

INSERT INTO user VALUES ('1', 'yiibai', '100', '2015-09-23 20:11:23');

CREATE TABLE post (

  post_id int(10) unsigned NOT NULL AUTO_INCREMENT,

  userid int(10) unsigned NOT NULL,

  title varchar(254) NOT NULL DEFAULT '',

  content text,

  created datetime NOT NULL DEFAULT '0000-00-00 00:00:00',

  PRIMARY KEY (post_id)

) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8;

INSERT INTO post VALUES ('1', '1', 'MyBatis关联数据查询', '在实际项目中，经常使用关联表的查询，比如：多对一，一对多等。这些查询是如何处理的呢，这一讲就讲这个问题。我们首先创建一个 post 表，并初始化数据.', '2015-09-23 21:40:17');

INSERT INTO post VALUES ('2', '1', 'MyBatis开发环境搭建', '为了方便学习，这里直接建立java 工程，但一般都是开发 Web 项目。', '2015-09-23 21:42:14');

INSERT INTO post VALUES ('3', '2', '这个是别人发的', 'content,内容...', '0000-00-00 00:00:00');

package mybatis.bean;

import java.io.Serializable;

public class Post implements Serializable{

	private int id;

	private User user;

	private String title;

	private String content;

	public int getId() {

		return id;

	}

	public void setId(int id) {

		this.id = id;

	}

	public User getUser() {

		return user;

	}

	public void setUser(User user) {

		this.user = user;

	}

	public String getTitle() {

		return title;

	}

	public void setTitle(String title) {

		this.title = title;

	}

	public String getContent() {

		return content;

	}

	public void setContent(String content) {

		this.content = content;

	}

}

package mybatis.bean;

import java.io.Serializable;

import java.util.Date;

import java.util.List;

public class User implements Serializable{

	private int id;

	private String username;

	private String mobile;

	private List<Post> posts;

	public int getId() {

		return id;

	}

	public void setId(int id) {

		this.id = id;

	}

	public String getUsername() {

		return username;

	}

	public void setUsername(String username) {

		this.username = username;

	}

	public String getMobile() {

		return mobile;

	}

	public void setMobile(String mobile) {

		this.mobile = mobile;

	}

	public List<Post> getPosts() {

		return posts;

	}

	public void setPosts(List<Post> posts) {

		this.posts = posts;

	}

	@Override

	public String toString() {

		return "User [id=" + id + ", name=" + username + "]";

	}

}

<?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>

<typeAliases>

		<typeAlias alias="User" type="mybatis.bean.User" />

		<typeAlias alias="Post" type="mybatis.bean.Post" />

</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://localhost:3306/mybatisonetomany"/>

		<property name="username" value="root"/>

		<property name="password" value="123456"/>

		</dataSource>

		</environment>

</environments>

<mappers>

	    <!-- // power by http://www.yiibai.com -->

	    <mapper resource="mybatis/bean/User.xml" />

</mappers>

</configuration>

<?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.zk.userMaper">

	<!-- User 级联文章查询 方法配置 (一个用户对多个文章)  -->

	<resultMap type="User" id="resultUserMap">

		<result property="id" column="user_id" />

		<result property="username" column="username" />

		<result property="mobile" column="mobile" />

		<collection property="posts" ofType="mybatis.bean.Post" column="userid">

			<id property="id" column="post_id" javaType="int" jdbcType="INTEGER"/>

            <result property="title" column="title" javaType="string" jdbcType="VARCHAR"/>

            <result property="content" column="content" javaType="string" jdbcType="VARCHAR"/>

		</collection>

	</resultMap>

	<select id="getUser" resultMap="resultUserMap" parameterType="int">

		SELECT u.*,p.*

		FROM user u, post p

		WHERE u.id=p.userid AND id=#{user_id}

  </select>

</mapper>

package MainApp;

import java.io.Reader;

import java.text.MessageFormat;

import java.util.List;

import mybatis.bean.Post;

import mybatis.bean.User;

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 Main {

	private static SqlSessionFactory sqlSessionFactory;

	private static Reader reader;

	static {

		try {

			reader = Resources.getResourceAsReader("config/config.xml");

			sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

		} catch (Exception e) {

			e.printStackTrace();

		}

	}

	public static SqlSessionFactory getSession() {

		return sqlSessionFactory;

	}

	/**

	 * @param args

	 */

	public static void main(String[] args) {

		// TODO Auto-generated method stub

		SqlSession session = sqlSessionFactory.openSession();

		try {

			int userid = 1;

			User user = session.selectOne("com.zk.userMaper.getUser", 1);

		     System.out.println("username: "+user.getUsername()+",");

                     List<Post> posts = user.getPosts();

                     for(Post p : posts) {

                         System.out.println("Title:" + p.getTitle());

                         System.out.println("Content:" + p.getContent());

                      }

		 } finally {

			session.close();

		 }

	}

}