iBatis2学习笔记：多对多映射(双向)

环境：
MySQL5.51b
iBatis 2.3
Spring 2.5.4
 
这个多对多不容易，费了好大劲才实现。
 
一、模型
 
用户（User）和角色（Role）之间是多对多的关系。
iBatis2学习笔记：多对多映射(双向)
 
二、SQL
/*==============================================================*/ 
/* Table: role                                                  */ 
/*==============================================================*/ 
create table role 
( 
   id                   bigint not null auto_increment, 
   rolename             varchar(24), 
   descp                varchar(240), 
   primary key (id) 
); 

alter table role comment '角色 
'; 

/*==============================================================*/ 
/* Table: tlink                                                 */ 
/*==============================================================*/ 
create table tlink 
( 
   userId               bigint not null, 
   roleId               bigint not null 
); 

alter table tlink comment '连接表'; 

/*==============================================================*/ 
/* Table: user                                                  */ 
/*==============================================================*/ 
create table user 
( 
   id                   bigint not null auto_increment, 
   username             varchar(24), 
   remark               varchar(240), 
   primary key (id) 
); 

alter table user comment '用户'; 

alter table tlink add constraint FK_r foreign key (roleId) 
      references role (id) on delete restrict on update restrict; 

alter table tlink add constraint FK_u foreign key (userId) 
      references user (id) on delete restrict on update restrict; 
 
三、POJO
/** 
* Created by IntelliJ IDEA.<br> 
* <b>User</b>: leizhimin<br> 
* <b>Date</b>: 2008-6-16 0:12:13<br> 
* <b>Note</b>: 用户角色多对多模型：角色 
*/ 
public class User { 
    private Long id; 
    private String username; 
    private String remark; 
    private List<Role> roleList = new ArrayList<Role>(); 


    public String toString() { 
        return "User{" + 
                "id=" + id + 
                ", username='" + username + '\'' + 
                ", remark='" + remark + '\'' + 
                ", roleList='" + roleList.size() + '\'' + 
                '}'; 
    } 

    public String out() { 
        StringBuffer sb = new StringBuffer(); 
        sb.append("User{" + 
                "id=" + id + 
                ", username='" + username + '\'' + 
                ", remark='" + remark + '\'' + 
                ", roleList='" + roleList.size() + '\''); 
        for (Role role : roleList) { 
            sb.append("\n\t").append(role.toString()); 
        } 
        return sb.toString(); 
    }
 
public class Role { 
    private Long id; 
    private String rolename; 
    private String descp; 
    private List<User> userList= new ArrayList<User>(); 

    public String toString() { 
        return "Role{" + 
                "id=" + id + 
                ", rolename='" + rolename + '\'' + 
                ", descp='" + descp + '\'' + 
                ", userList=" + userList.size() + 
                '}'; 
    } 

    public String out(){ 
        StringBuffer sb= new StringBuffer(); 
        if(userList.size()>0){ 
            sb.append("Role{" + 
                "id=" + id + 
                ", rolename='" + rolename + '\'' + 
                ", descp='" + descp + '\'' + 
                ", userList=" + userList.size()); 
            for(User u: userList){ 
                sb.append("\n\t").append(u.toString()); 
            } 
            sb.append("\n}"); 
        } 
        return sb.toString(); 
    } 
 
/** 
* Created by IntelliJ IDEA.<br> 
* <b>User</b>: leizhimin<br> 
* <b>Date</b>: 2008-6-16 0:17:15<br> 
* <b>Note</b>: 用户角色多对多模型：连接表 
*/ 
public class Tlink { 
    private Long id; 
    private Long userId; 
    private Long roleId;
 
四、SqlMap
User.xml
<?xml version="1.0" encoding="UTF-8" ?> 
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd" > 
<sqlMap namespace="user"> 
    <typeAlias alias="user" type="com.lavasoft.ssi.domain.User"/> 
    <resultMap id="result_basc" class="user"> 
        <result property="id" column="id"/> 
        <result property="username" column="username"/> 
        <result property="remark" column="remark"/> 
    </resultMap> 

    <resultMap id="result" class="user" extends="result_basc"> 
        <result property="roleList" column="id" select="role.getByUserId"/> 
    </resultMap> 


    <insert id="insert" parameterClass="user"> 
        insert into user(username,remark) values(#username#,#remark#) 
        <selectKey keyProperty="id" resultClass="long"> 
            select LAST_INSERT_ID() 
        </selectKey> 
    </insert> 
    <select id="getById" parameterClass="long" resultMap="result_basc"> 
        select * from user where id = #value# 
    </select> 

    <select id="getWithCashWithRoleList" parameterClass="long" resultMap="result"> 
        select * from user where id = #value# 
    </select> 

    <select id="getByRoleId" parameterClass="long" resultMap="result_basc"> 
        select u.* from user u where u.id in 
        (select userId from tlink where roleId=#value#) 
    </select> 


</sqlMap>
 
Role.xml
<?xml version="1.0" encoding="UTF-8" ?> 
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd" > 
<sqlMap namespace="role"> 
    <typeAlias alias="role" type="com.lavasoft.ssi.domain.Role"/> 
    <resultMap id="result_basc" class="role"> 
        <result property="id" column="id"/> 
        <result property="rolename" column="rolename"/> 
        <result property="descp" column="descp"/> 
    </resultMap> 
    <resultMap id="result" class="role" extends="result_basc"> 
        <result property="userList" column="id" select="user.getByRoleId"/> 
    </resultMap> 
    <insert id="insert" parameterClass="role"> 
        insert into role(rolename,descp) values(#rolename#,#descp#) 
        <selectKey keyProperty="id" resultClass="long"> 
            select LAST_INSERT_ID() 
        </selectKey> 
    </insert> 
    <select id="getById" parameterClass="long" resultMap="result_basc"> 
        select * from role where id = #value# 
    </select> 

    <select id="getRoleByIdWithCashUser" parameterClass="long" resultMap="result"> 
        select * from role where id = #value# 
    </select> 

    <!--为多对多配置--> 
    <select id="getByUserId" parameterClass="long" resultClass="role" resultMap="result_basc"> 
        select r.* from role r where r.id in 
        (select roleId from tlink where userId=#value#) 
    </select> 
</sqlMap>
 
Tlink.xml
<?xml version="1.0" encoding="UTF-8" ?> 
<!DOCTYPE sqlMap PUBLIC "-//ibatis.apache.org//DTD SQL Map 2.0//EN" "http://ibatis.apache.org/dtd/sql-map-2.dtd" > 
<sqlMap namespace="tlink"> 
    <typeAlias alias="tlink" type="com.lavasoft.ssi.domain.Tlink"/> 
    <resultMap id="result" class="tlink"> 
        <result property="id" column="id"/> 
        <result property="userId" column="userId"/> 
        <result property="roleId" column="roleId"/> 
    </resultMap> 
    <insert id="insert" parameterClass="tlink"> 
        insert into tlink(userId,roleId) values(#userId#,#roleId#) 
        <selectKey keyProperty="id" resultClass="long"> 
            select LAST_INSERT_ID() 
        </selectKey> 
    </insert> 
    <select id="getByUserId" parameterClass="long" resultMap="result"> 
        select * from tlink where userId = #value# 
    </select> 
    <select id="getByRoleId" parameterClass="long" resultMap="result"> 
        select * from tlink where roleId = #value# 
    </select> 
    <delete id="delete" parameterClass="tlink"> 
        delete from tlink where userId = #userId# and roleId = #roleId# 
    </delete> 

</sqlMap>
 
五、DAO
public interface UserDAO { 
    public Long insert(User user); 
    public Object getById(Long id); 
    public Object getWithCashById(Long id); 
    public User getWithCashWithRoleList(Long id); 
} 
 
public interface RoleDAO { 
    public Long insert(Role role); 
    public Role getById(Long id); 
    public Role getRoleByIdWithCashUser(Long id); 
    public List<Role> getByUserId(Long userId); 
}
 
public interface TlinkDAO { 
    public void insert(Long userId,Long roleId); 
    public int delete(Long userId,Long roleId); 
    public int update(Long userId,Long roleId); 
}
 
public class UserDAOImpl extends SqlMapClientDaoSupport implements UserDAO { 
    public Long insert(User user) { 
        return (Long) getSqlMapClientTemplate().insert("user.insert",user); 
    } 

    public Object getById(Long id) { 
        return getSqlMapClientTemplate().queryForList("user.getById",id); 
    } 

    public Object getWithCashById(Long id) { 
        return getSqlMapClientTemplate().queryForList("user.getWithCashById",id); 
    } 

    public User getWithCashWithRoleList(Long userId) { 
        return (User) getSqlMapClientTemplate().queryForObject("user.getWithCashWithRoleList",userId); 
    } 
}
 
public class RoleDAOImpl extends SqlMapClientDaoSupport implements RoleDAO { 
    public Long insert(Role role) { 
        return (Long) getSqlMapClientTemplate().insert("role.insert",role); 
    } 

    public Role getById(Long id) { 
        return (Role) getSqlMapClientTemplate().queryForObject("role.getById",id); 
    } 

    public Role getRoleByIdWithCashUser(Long id) { 
        return (Role) getSqlMapClientTemplate().queryForObject("role.getRoleByIdWithCashUser",id); 
    } 

    public List<Role> getByUserId(Long userId) { 
        return getSqlMapClientTemplate().queryForList("role.getByUserId",userId); 
    } 
}
 
public class TlinkDAOImpl extends SqlMapClientDaoSupport implements TlinkDAO { 
    public void insert(Long userId, Long roleId) { 
        Tlink tlink = new Tlink(userId, roleId); 
        getSqlMapClientTemplate().insert("tlink.insert",tlink); 
    } 

    public int delete(Long userId, Long roleId) { 
        Tlink tlink = new Tlink(userId, roleId); 
        return getSqlMapClientTemplate().delete("tlink.delete",tlink); 
    } 

    public int update(Long userId, Long roleId) { 
        return 0; 
    } 
}
 
 
六、测试类
public class UserDAOTest{ 
    private UserDAO userDAO = (UserDAO) ApplicationContextUtils.getApplicationContext().getBean("userDAO"); 

    public void testInsert() { 
        System.out.println("-------insert(User user)--------"); 
        User user = new User(); 
        user.setUsername("熔岩"); 
        user.setRemark("系统用户"); 
        Long pk = userDAO.insert(user); 
        System.out.println("所插入数据ID=" + pk); 
    } 

    public void testGetById() { 
        System.out.println("-------getById(Long id)-------"); 
        Object object = userDAO.getById(3L); 
        System.out.println(object); 
    } 

    public void testGetWithCashById() { 
        System.out.println("-------getWithCashById(Long id)-------"); 
        Object object = userDAO.getWithCashById(1L); 
        System.out.println(object); 
    } 

    public void getWithCashWithRoleList(){ 
        System.out.println("-------getWithCashWithRoleList()-------"); 
        User user = userDAO.getWithCashWithRoleList(1L); 
        System.out.println(user.out()); 
    } 

    public static void main(String args[]){ 
        System.out.println("正在测试UserDAO"); 
        UserDAOTest userDAOTest  = new UserDAOTest(); 
        userDAOTest.testInsert(); 
        userDAOTest.testGetById(); 
        userDAOTest.getWithCashWithRoleList(); 
    } 
}
 
/** 
* Created by IntelliJ IDEA.<br> 
* <b>User</b>: leizhimin<br> 
* <b>Date</b>: 2008-6-16 1:05:57<br> 
* <b>Note</b>: 用户角色多对多模型：角色 
*/ 
public class RoleDAOTest{ 
    RoleDAO roleDAO = (RoleDAO) ApplicationContextUtils.getApplicationContext().getBean("roleDAO"); 
    public void testInsert() { 
        System.out.println("------insert(Role role)-----"); 
        Role role = new Role(); 
        role.setRolename("admin"); 
        role.setDescp("管理员"); 
        Long pk = roleDAO.insert(role); 
        System.out.println("所插入数据ID="+pk); 
    } 

    public void testGetById() { 
        System.out.println("------getById(Long id)-----"); 
        Object obj = roleDAO.getById(1L); 
        System.out.println("查询结果"+obj); 
    } 

    public void testGetRoleByIdWithCashUser() { 
        System.out.println("------getRoleByIdWithCashUser(Long id)-----"); 
        Role obj = roleDAO.getRoleByIdWithCashUser(1L); 
        System.out.println("查询结果"+obj.out()); 
    } 

    public void testGetByUserId(){ 
        System.out.println("------getByUserId(Long userId)-----"); 
        List<Role> roleList= roleDAO.getByUserId(1L); 
        for(Role r: roleList){ 
            System.out.println(r); 
        }         
    } 

    public static void main(String args[]){ 
        System.out.println("正在测试RoleDAO"); 
        RoleDAOTest roleDAOTest = new RoleDAOTest(); 
        roleDAOTest.testInsert(); 
        roleDAOTest.testGetById(); 
        roleDAOTest.testGetRoleByIdWithCashUser(); 
        roleDAOTest.testGetByUserId(); 
    } 
}
 
public class TlinkDAOTest { 
    TlinkDAO tlinkDAO = (TlinkDAO) ApplicationContextUtils.getApplicationContext().getBean("tlinkDAO"); 

    public void testInsert(){ 
        tlinkDAO.insert(1L,1L); 
        tlinkDAO.insert(1L,2L); 
        tlinkDAO.insert(1L,3L); 
    } 

    public static void main(String args[]){ 
        TlinkDAOTest tlinkDAOTest = new TlinkDAOTest(); 
        tlinkDAOTest.testInsert(); 
    } 
}
 
七、测试结果
正在测试UserDAO 
log4j:WARN No appenders could be found for logger (org.springframework.context.support.ClassPathXmlApplicationContext). 
log4j:WARN Please initialize the log4j system properly. 
-------insert(User user)-------- 
所插入数据ID=10 
-------getById(Long id)------- 
[User{id=3, username='熔岩', remark='系统用户', roleList='0'}] 
-------getWithCashWithRoleList()------- 
User{id=1, username='熔岩', remark='系统用户', roleList='3' 
    Role{id=1, rolename='r1', descp='aaa', userList=0} 
    Role{id=2, rolename='r2', descp='bbb', userList=0} 
    Role{id=3, rolename='r3', descp='ccc', userList=0} 

Process finished with exit code 0
 
 
正在测试RoleDAO 
log4j:WARN No appenders could be found for logger (org.springframework.context.support.ClassPathXmlApplicationContext). 
log4j:WARN Please initialize the log4j system properly. 
------insert(Role role)----- 
所插入数据ID=10 
------getById(Long id)----- 
查询结果Role{id=1, rolename='r1', descp='aaa', userList=0} 
------getRoleByIdWithCashUser(Long id)----- 
查询结果Role{id=1, rolename='r1', descp='aaa', userList=3 
    User{id=1, username='熔岩', remark='系统用户', roleList='0'} 
    User{id=2, username='熔岩', remark='系统用户', roleList='0'} 
    User{id=3, username='熔岩', remark='系统用户', roleList='0'} 
} 
------getByUserId(Long userId)----- 
Role{id=1, rolename='r1', descp='aaa', userList=0} 
Role{id=2, rolename='r2', descp='bbb', userList=0} 
Role{id=3, rolename='r3', descp='ccc', userList=0} 

Process finished with exit code 0
 
测试结果表明：双向多对多彻底搞定！
 

本文转自 leizhimin 51CTO博客，原文链接：http://blog.51cto.com/lavasoft/83905，如需转载请自行联系原作者

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