Mybatis多表连接多对多例子工程（补充易百教程缺失部分）

一、工程目录如下：

 二、

（一）Main.java

import java.io.Reader;
import java.text.MessageFormat;
import java.util.List;

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 com.yiibai.maper.GroupMaper;
import com.yiibai.maper.UserGroupMaper;
import com.yiibai.maper.UserMaper;
import com.yiibai.pojo.Group;
import com.yiibai.pojo.User;
import com.yiibai.pojo.UserGroup;

public class Main {
    private static SqlSessionFactory sqlSessionFactory;
    private static Reader reader;

    static {
        try {
            reader = Resources.getResourceAsReader("config/Configure.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
        // testAddGroup();
        // testAddUser();
        //testAddUserGroup();
        testGetGroupAndUsers();
        
    }
    
    /*
    public static void testGetGroupAndUsers() {
        UserGroup userGroup = new UserGroup();
        SqlSession session = sqlSessionFactory.openSession();
        try {
            GroupMaper groupMaper = session.getMapper(GroupMaper.class);
            Group group = groupMaper.getGroup(1);
            System.out.println("Group => " + group.getGroupName());
            List<User> users = group.getUsers();
            for (User user : users) {
                System.out.println("\t:" + user.getId() + "\t"
                        + user.getUsername());
            }
        } finally {
            session.close();
        }
    }
    */
    public static void testGetGroupAndUsers() {
        UserGroup userGroup = new UserGroup();
        userGroup.getUserId();
        SqlSession session = sqlSessionFactory.openSession();
        try {
            GroupMaper groupMaper = session.getMapper(GroupMaper.class);
            Group group = groupMaper.getGroups(1);
            System.out.println("Group => " + group.getGroupName());
            List<User> users = group.getUsers();
            for (User user : users) {
                System.out.println("\t:" + user.getId() + "\t"
                        + user.getUsername());
            }
        } finally {
            session.close();
        }
    }
    
/*
    public static void testAddUserGroup() {
        UserGroup userGroup = new UserGroup();
        userGroup.setGroupId(1);
        userGroup.setUserId(2);
        SqlSession session = sqlSessionFactory.openSession();
        try {
            UserGroupMaper userGroupMaper = session
                    .getMapper(UserGroupMaper.class);
            userGroupMaper.insertUserGroup(userGroup);

            session.commit();
        } finally {
            session.close();
        }

    }
*/

    public static void testAddUser() {
        // TODO Auto-generated method stub
        SqlSession session = sqlSessionFactory.openSession();
        try {
            User user = new User();
            user.setUsername("User-name-1");
            user.setMobile("13838009988");
            UserMaper userMaper = session.getMapper(UserMaper.class);
            userMaper.insertUser(user);
            session.commit();
            // System.out.println(user.getGroupId());
        } finally {
            session.close();
        }
    }

    public static void testAddGroup() {
        // TODO Auto-generated method stub
        SqlSession session = sqlSessionFactory.openSession();
        try {
            Group group = new Group();
            group.setGroupName("用户组-1");
            GroupMaper groupMapper = session.getMapper(GroupMaper.class);
            groupMapper.insertGroup(group);
            session.commit();
            System.out.println(group.getGroupId());
        } finally {
            session.close();
        }
    }
}

（二）GroupMaper.java

package com.yiibai.maper;

import com.yiibai.pojo.Group;

public interface GroupMaper {
    
    public Group getGroups(int groupId);
    
    public Group insertGroup(Group group);
}

（三）UserGroupMaper.java

package com.yiibai.maper;

import java.util.List;

import com.yiibai.pojo.Group;
import com.yiibai.pojo.User;
import com.yiibai.pojo.UserGroup;

public interface UserGroupMaper {
    public User getUsersByGroupId(int groudId);
    public List<Group> getGroupListByUserId(int userId);
    public List<User> getUserListByGroupId(int groupId);
    
    //public UserGroup insertUserGroup(UserGroup userGroup);
    public Group getGroupsByUserId(int userId);
}

（四）UserMaper .java

package com.yiibai.maper;

import java.util.List;

import com.yiibai.pojo.User;


/**
 * @author wuchao
 * @time 上午9:44:06
 *
 */
public interface UserMaper {

    public User getUser(int userId);
    public User insertUser(User user);
    public List<User> getAllUserGroupe();
}

（五）GroupMaper.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.yiibai.maper.GroupMaper">

	<parameterMap type="Group" id="parameterGroupMap">
		<parameter property="groupId"/>
		<parameter property="groupName"/>
	</parameterMap>
	<insert id="insertGroup" parameterMap="parameterGroupMap">
		INSERT INTO `group` (group_name)
		VALUES(#{groupName}); 
	</insert>

	<resultMap type="Group" id="resultGroupMap_1">
		<result property="id" column="id" />
		<result property="groupName" column="group_name" />
		<collection property="users" column="group_id"
			select="com.yiibai.maper.UserGroupMaper.getUsersByGroupId" />
	</resultMap>
	<select id="getGroups" resultMap="resultGroupMap_1"
		parameterType="int">
		SELECT *
		FROM `group`
		WHERE group_id=#{id}
	</select>
</mapper>	

（六）UserGroupMaper.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.yiibai.maper.UserGroupMaper">
	<parameterMap type="UserGroup" id="parameterUserGroupMap">
		<parameter property="userId"/>
		<parameter property="groupId"/>
	</parameterMap>
	
	<insert id="insertUserGroup"  parameterMap="parameterUserGroupMap">
		INSERT INTO user_group(user_id, group_id)
		VALUES(#{userId},#{groupId})
	</insert>
	
	<!-- 根据一个用户组ID,查看这个用户组下的所有用户 -->
	<resultMap type="User" id="resultUserMap_2">
		<result property="id" column="id"/>
		<result property="username" column="username"/>
		<result property="mobile" column="mobile"/>
	</resultMap>
	
	<select id="getUsersByGroupId" resultMap="resultUserMap_2" parameterType="int">
		SELECT u.*, ug.group_id
		FROM user u, user_group ug
		WHERE u.id=ug.user_id AND ug.group_id=#{group_id}
	</select>
	
	<!-- 根据一个用户ID,查看这个用户所对应的组-->
	<resultMap type="Group" id="resultGroupMap_2">
		<result property="groupId" column="group_id"/>
		<result property="groupName" column="group_name"/>
	</resultMap> 
	
	<select id="getGroupsByUserId" resultMap="resultGroupMap_2" parameterType="int">
		SELECT g.*, u.user_id
		FROM group g, user_group u
		WHERE g.group_id=u.group_id AND u.user_id=#{user_id}
	</select>
</mapper>	

（七）UserMaper.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.yiibai.maper.UserMaper">
	<parameterMap type="User" id="parameterUserMap">
		<parameter property="id"/>
		<parameter property="username"/>
		<parameter property="mobile"/>
	</parameterMap>
	
	<insert id="insertUser" parameterMap="parameterUserMap">	
		INSERT INTO user(username,mobile)
		VALUES(#{username},#{mobile});
	</insert>   
	
	<resultMap type="User" id="resultUser">
		<result property="id" column="group_id"/>
		<result property="name" column="name"/>
		<collection property="groups" column="id" select="com.yiibai.maper.UserGroupMaper.getGroupsByUserId"/>
	</resultMap>
	
	<select id="getUsers" resultMap="resultUser" parameterType="int">
		SELECT *
		FROM user
		WHERE id=#{id}
	</select>    
</mapper>

（八）Group.java

package com.yiibai.pojo;

import java.util.List;

/** 
 * @describe: Group
 * @author: Yiibai 
 * @version: V1.0
 * @copyright http://www.yiibai.com
 */  
public class Group {
	private int groupId;
	private String groupName;
	private List<User> users;
	
	public List<User> getUsers() {
		return users;
	}
	public void setUsers(List<User> users) {
		this.users = users;
	}
	public int getGroupId() {
		return groupId;
	}
	public void setGroupId(int groupId) {
		this.groupId = groupId;
	}
	public String getGroupName() {
		return groupName;
	}
	public void setGroupName(String groupName) {
		this.groupName = groupName;
	}
	
}

（九）User.java

package com.yiibai.pojo;

import java.util.List;

/** 
 * @describe: User
 * @author: Yiibai 
 * @version: V1.0
 * @copyright http://www.yiibai.com
 */  
public class User {
	private int id;
	private String username;
	private String mobile;
	private List<Group> groups;
	public List<Group> getGroups() {
		return groups;
	}
	public void setGroups(List<Group> groups) {
		this.groups = groups;
	}
	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;
	}
	
}

（十）UserGroup.java

package com.yiibai.pojo;

public class UserGroup {
	private int userId;  
    private int groupId;
	public int getUserId() {
		return userId;
	}
	public void setUserId(int userId) {
		this.userId = userId;
	}
	public int getGroupId() {
		return groupId;
	}
	public void setGroupId(int groupId) {
		this.groupId = groupId;
	}
 
    
}

（十一）Configure.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>
	<typeAliases>
		<typeAlias alias="User" type="com.yiibai.pojo.User" />
		<typeAlias alias="UserGroup" type="com.yiibai.pojo.UserGroup" />
		<typeAlias alias="Group" type="com.yiibai.pojo.Group" />
	</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/yiibai" />
			    <property name="username" value="root" />
			    <property name="password" value="root" />
                       </dataSource>
		</environment>
	</environments>

	<mappers>
	     <!-- // power by http://www.yiibai.com -->
	     <mapper resource="com/yiibai/maper/UserMaper.xml" />
		 <mapper resource="com/yiibai/maper/GroupMaper.xml" />
		 <mapper resource="com/yiibai/maper/UserGroupMaper.xml" />
	</mappers>
</configuration>