MyBatis進行一對多的關聯表操作

一、准備t_role 、t_role_promission、t_promission表

CREATE TABLE `t_role` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `sn` varchar(255) NOT NULL,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=19 DEFAULT CHARSET=utf8;

CREATE TABLE `t_permission` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `url` varchar(255) NOT NULL,
  `sn` varchar(255) NOT NULL,
  `systemmenu_id` bigint(20) DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `qwe` (`systemmenu_id`),
  CONSTRAINT `qwe` FOREIGN KEY (`systemmenu_id`) REFERENCES `t_systemmenu` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=utf8;

CREATE TABLE `t_role_permission` (
  `role_id` bigint(20) NOT NULL DEFAULT '0',
  `permission_id` bigint(20) NOT NULL DEFAULT '0',
  PRIMARY KEY (`role_id`,`permission_id`),
  KEY `wl` (`permission_id`),
  CONSTRAINT `wl` FOREIGN KEY (`permission_id`) REFERENCES `t_permission` (`id`),
  CONSTRAINT `wq` FOREIGN KEY (`role_id`) REFERENCES `t_role` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

二、准備role和permission的domain表，

public class Role {

    private Long id;

    private String sn;//編碼  admin

    private String name;//名稱  超級管理員

    private List<Permission> permissions;//角色對應的權限

    //省略了get、set      
}

public class Permission {
    private Long id;

    private String name;

    private String url;//權限路徑  /employee/save

    private String sn;//編碼  employee:save

    private Long systemmenuId;//菜單
  
 　　// 省略get、set    
}

由於mabatis沒有級聯操作，所以我們將中間表也需要建立一個domain

public class RolePermission {

    private Role role;
    private Permission permission;
  
　　//省略get、set    
}

三、mabatis一對多關聯查詢

RoleMapper.xml

<mapper namespace="com.wangshifu.car_repair.mapper.RoleMapper" >
  <resultMap id="BaseResultMap" type="com.wangshifu.car_repair.domain.Role" >
    <id column="id" property="id" jdbcType="BIGINT" />
    <result column="sn" property="sn" jdbcType="VARCHAR" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <collection property="permissions" ofType="com.wangshifu.car_repair.domain.Permission"
      column="id" select="com.wangshifu.car_repair.mapper.PermissionMapper.selectPermission"
    >
     <!-- <id column="pid" property="id" />
      <result column="pname" property="name" />
      <result column="purl" property="url" />
      <result column="psn" property="sn" />-->
    </collection>
  </resultMap>
<!--分頁查詢-->
  <select id="selectQuery" resultMap="BaseResultMap" parameterType="com.wangshifu.car_repair.query.RoleQuery" >
    /*select r.id, r.sn, r.name,p.id pid,p.name pname,p.url purl,p.sn psn
    from t_role r left join t_role_permission rp ON r.id=rp.role_id
    left JOIN t_permission p ON p.id =rp.permission_id*/
    select distinct id, sn, name
    from t_role
    /*高級查詢*/
  <where>
    <if test="name !=null and name!=''">
      and r.name like concat('%',#{name},'%')
    </if>
  </where>
  </select>

<!--  permission.xml     查詢角色權限-->
  <select id="selectPermission" resultMap="BaseResultMap"  parameterType="com.wangshifu.car_repair.domain.Role">
  select p.*
    from t_role r join t_role_permission rp ON r.id=rp.role_id
  JOIN t_permission p ON p.id =rp.permission_id where r.id=#{id}
  </select>

四、mabatis關聯查詢出現的分頁問題

在上面我這里分別用了嵌套查詢（注釋部分）和嵌套結果，最開始使用的是嵌套查詢，發現前台的分頁是先將數據查詢出來然后進行的分頁，這樣就導致的分頁的錯誤信息，

 

所以得使用嵌套結果，將這倆條sql獨立，先將需要進行分頁的數據進行分頁，再將關聯表的數據加入進來，分頁信息就ok了。

 

五、mabatis一對多關聯增、刪、改

<!--   roleMapper.xml   角色權限添加-->
  <insert id="insertRoleAndPermission" parameterType="com.wangshifu.car_repair.domain.RolePermission">
    insert into t_role_permission (role_id, permission_id)
    values (#{role.id}, #{permission.id});
  </insert>
  <!--角色權限修改-->
  <update id="updateRoleAndPermission" parameterType="com.wangshifu.car_repair.domain.RolePermission">
    update t_role_permission
    set  permission_id = #{permission.id}
    where role_id = #{role.id,jdbcType=BIGINT}
    and permission_id=#{permission.id,jdbcType=BIGINT}
  </update>
  <!--角色權限刪除-->
  <delete id="deleteRoleAndPermission" parameterType="com.wangshifu.car_repair.domain.RolePermission" >
    delete from t_role_permission
    where role_id = #{role.id,jdbcType=BIGINT}
    and permission_id=#{permission.id,jdbcType=BIGINT}
  </delete>

六、mabatis一對多關聯增、刪、改java代碼部分

@Controller
@RequestMapping("/role")
public class RoleController {

    @Autowired
    private IRoleService roleService;
    @Autowired
    private IPermissionService permissionService;


    @RequestMapping("/delete")
    @ResponseBody
    public AjaxResult delete(Long id){
        try {
            //查詢角色
            Role role = roleService.findOne(id);
            //查詢權限
            List<Permission> permissionsList = permissionService.selectPermission(role);
            permissionsList.forEach(e->{
                //先刪除中間表
                roleService.deleteRoleAndPermission(new RolePermission(role, e));
            });
            //再刪除角色表
            roleService.delete(id);
            return new AjaxResult();
        } catch (Exception e) {
            e.printStackTrace();
            return new AjaxResult(e.getMessage());
        }
    }


    @RequestMapping("/save")
    @ResponseBody
    public AjaxResult save(Role role){
        try {
            //該角色權限（只有id，前台傳過來的）
            List<Permission> permissions = role.getPermissions();
            //保存角色返回主鍵（需要在對應mapper.xml配置屬性）
            roleService.save(role);
            //如果有權限
            if(permissions.size()>0){
                permissions.forEach(e->{
                    //保存中間表
                    roleService.insertRoleAndPermission(new RolePermission(role, e));
                });
            }
            return new AjaxResult();
        } catch (Exception e) {
            e.printStackTrace();
            return new AjaxResult(e.getMessage());
        }
    }

    @RequestMapping("/update")
    @ResponseBody
    public AjaxResult update(Role role){
        try {
            //該角色最新的權限（有id）
            List<Permission> permissions = role.getPermissions();
            //原來的權限
            List<Permission> permissionList = permissionService.selectPermission(role);
            if(permissionList.size()>0){
                permissionList.forEach(e->{
                    //先刪除原有關系中間表
                    roleService.deleteRoleAndPermission(new RolePermission(role, e));
                });
            }
           if( permissions!=null  && permissions.size()>0 ){
               permissions.forEach(p->{
                   //添加最新的權限中間表
                   roleService.insertRoleAndPermission(new RolePermission(role, p));
               });
           }
            //最后修改角色表（因為外鍵關聯、需要在中間表操作后才操作）
            roleService.update(role);
            return new AjaxResult();
        } catch (Exception e) {
            e.printStackTrace();
            return new AjaxResult(e.getMessage());
        }
    }
}