JVAVA递归查询数据库,生成tree菜单

亦凉 2024-03-25 20:06 40阅读 0赞

### **serviceImpl.java(业务实现层代码)** ###

/**
         * 根据用户名username和系统systemName去查询菜单信息
         * @param username 用户名
         * @param systemName 系统名称
         * @param parentId 父id(第一次默认传null,表示第一次查的是第一级菜单)
         * @return
         */
        @Override
        public List<SysMenu> findMenusByUserName(String username,String systemName,Long parentId){
    
            List<SysMenu> listMenus;
            /*第一级*/
            listMenus = menuDao.findMenusByUserName(username,systemName,parentId);
            if(listMenus != null && !listMenus.isEmpty()){
                for (SysMenu menu:listMenus) {
                    setChildMenus(menu,username,systemName);
                }
            }
            return listMenus;
        }
    
    
        /**
         * 递归
         * @param sysMenu 菜单对象
         * @param username 用户名
         * @param systemName 系统名称
         */
        private void setChildMenus(SysMenu sysMenu,String username,String systemName){
            List<SysMenu> result = menuDao.findMenusByUserName(username, systemName,sysMenu.getId());
            if(result != null && !result.isEmpty()){
                sysMenu.setSubMenus(result);
                for (SysMenu menu:result) {
                    setChildMenus(menu,username,systemName);
                }
            }
        }

### **dao.java代码** ###

/**
         * 根据用户名username和系统systemName去查询菜单信息
         * @param username
         * @return
         */
        List<SysMenu> findMenusByUserName(@Param("username")String username,@Param("systemName")String systemName,@Param("parentId")Long parentId);

### **dao.xml代码** ###

<select id="findMenusByUserName" resultType="com.open.capacity.model.system.SysMenu">
            SELECT e.* from sys_user a
                LEFT JOIN sys_role_user b on a.id=b.userId
                LEFT JOIN sys_role c on c.id=b.roleId
                LEFT JOIN sys_role_menu d on d.roleId=c.id
                LEFT JOIN sys_menu e ON e.id=d.menuId
                LEFT JOIN sys_role_permission f ON f.roleId=c.id
                LEFT JOIN sys_permission g ON f.permissionId=g.id
                LEFT JOIN sys_system h ON h.id=g.systemId
                WHERE 1=1
                <if test="username!=null and username!=''">
                    AND a.username=#{username}
                </if>
                <if test="systemName!=null and systemName!=''">
                    AND h.name=#{systemName}
                </if>
                <if test="parentId == null">
                    AND e.parentId=-1
                </if>
                <if test="parentId != null and parentId != ''">
                    AND e.parentId=#{parentId}
                </if>
                AND e.id IS NOT NULL  GROUP BY e.id
        </select>

本文链接：[https://blog.csdn.net/yuanting\_/article/details/93189987][https_blog.csdn.net_yuanting_article_details_93189987]

[https_blog.csdn.net_yuanting_article_details_93189987]: https://blog.csdn.net/yuanting_/article/details/93189987