java 递归 树形

//菜单树形结构
   public JSONArray treeMenuList(JSONArray menuList, int parentId) {
       JSONArray childMenu = new JSONArray();
       for (Object object : menuList) {
           JSONObject jsonMenu = JSONObject.fromObject(object);
           int menuId = jsonMenu.getInt("id");
           int pid = jsonMenu.getInt("parentId");
           if (parentId == pid) {
               JSONArray c_node = treeMenuList(menuList, menuId);
               jsonMenu.put("childNode", c_node);
               childMenu.add(jsonMenu);
           }
       }
       return childMenu;
   }

public static void main(String args[]) {
       MenuCacheService menuCacheService = new MenuCacheService();
       JSONArray jsonArray = new JSONArray();
       Menu menu1 = new Menu();
       menu1.setId(1l);
       menu1.setParentId(0);
       menu1.setLevel(0);
       Menu menu2 = new Menu();
       menu2.setId(2l);
       menu2.setParentId(0);
       menu2.setLevel(0);
       Menu menu3 = new Menu();
       menu3.setId(3l);
       menu3.setParentId(2);
       menu3.setLevel(1);
       Menu menu4 = new Menu();
       menu4.setId(4l);
       menu4.setParentId(2);
       menu4.setLevel(1);
       Menu menu5 = new Menu();
       menu5.setId(5l);
       menu5.setParentId(4);
       menu5.setLevel(2);
       Menu menu6 = new Menu();
       menu6.setId(6l);
       menu6.setParentId(1);
       menu6.setLevel(1);

       jsonArray.add(menu1);
       jsonArray.add(menu2);
       jsonArray.add(menu3);
       jsonArray.add(menu4);
       jsonArray.add(menu5);
       jsonArray.add(menu6);

       System.out.print(menuCacheService.treeMenuList(jsonArray,0));
   }