java 递归遍历树形结构

好记性不如烂笔头，记录下。

//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));
}