關於有層級關係時返回前端樹狀json
阿新 • • 發佈：2018-12-04
結果 { "message": [ { "children": [ { "children": [ { "children": [ { "empno": "7876","ename": "ADAMS", "mgr": "7788", "sal": "1100" } ], "empno": "7788", "ename": "SCOTT","mgr": "7566", "sal": "3000" }, { "children": [ { "empno": "7369", "ename": "SMITH","mgr": "7902", "sal": "800" } ], "empno": "7902", "ename": "FORD", "mgr": "7566", "sal": "3000" } ], "empno": "7566", "ename": "JONES", "mgr": "7839", "sal": "2975" }, { "children": [ { "empno": "7499", "ename": "ALLEN", "mgr": "7698", "sal": "1600" }, { "empno": "7521", "ename": "WARD", "mgr": "7698", "sal": "1250" }, { "empno": "7654", "ename": "MARTIN", "mgr": "7698", "sal": "1250" }, { "empno": "7844", "ename": "TURNER", "mgr": "7698", "sal": "1500" }, { "empno": "7900", "ename": "JAMES", "mgr": "7698", "sal": "950" } ], "empno": "7698", "ename": "BLAKE", "mgr": "7839", "sal": "2850" }, { "children": [ { "empno": "7934", "ename": "MILLER", "mgr": "7782", "sal": "1300" } ], "empno": "7782", "ename": "CLARK", "mgr": "7839", "sal": "2450" } ], "empno": "7839", "ename": "KING", "mgr": "0", "sal": "5000" } ] }
1：資料庫為Oracle的emp表找出King的所有下屬
<select id="testBigDecimal25" resultType="com.mayi.vo.Menu"> select empno, ename, sal, mgr from emp </select>
一個javaBean
public class Menu { private String empno; private String ename; private String sal; private String mgr; //選單標識 // private Meta meta; //子選單 private List<Menu> children; get set自補
遞迴查子
public JSONObject getInfo() {
System.out.println("iiiii");
List<Menu> list=dao.testBigDecimal24(s1.concat(".testBigDecimal25"), null);
System.out.println(list);
//呼叫TreeTest工具類方法生成樹形結構的List集合
List<Menu> treeList = TreeUtil.listToTree(list);
//使用fastjson對樹形list件序列化轉成json字串,過濾掉屬性值為null的屬性
String message = JSON.toJSONString(treeList,SerializerFeature.PrettyFormat);
JSONObject returnData = new JSONObject();
//重新將json字串轉成jsonObject物件,返回給前端
returnData.put("message",JSON.parse(message));
//return CommonUtil.successJson(returnData);
return returnData;
}
utils
//用List構建帶有層次結構的json資料 //List父子節點構造樹形Json public class TreeUtil { //將list集合轉成樹形結構的list集合 public static List<Menu> listToTree(List<Menu> list) { //用遞迴找子。 List<Menu> treeList = new ArrayList<Menu>(); for (Menu tree : list) { if (tree.getMgr().equals("0")) { //這個地方注意報空指標====== treeList.add(findChildren(tree, list)); } } return treeList; } //尋找子節點 private static Menu findChildren(Menu tree, List<Menu> list) { for (Menu node : list) { if (node.getMgr().equals(tree.getEmpno())) { if (tree.getChildren() == null) { tree.setChildren(new ArrayList<Menu>()); } tree.getChildren().add(findChildren(node, list)); } } return tree; } }