jquery-easyui中创建异步加载树

jquery-easyui中创建异步加载树

objectexceptionasynchronousintegernullclass

easyui中的树可以从标记中建立，也可以通过指定一个URL属性读取数据建立。如果想建立一棵异步树，需要为每个节点指定一个id属性值，这样在加载数据时会自动向后台传递id参数。

Html代码

1.

编写前台代码：

Js代码

1.$('#tt').tree({

2. url:'/demo2/node/getNodes'// The url will be mapped to NodeController class and getNode

s method

3.});

为测试用，建立一个节点的数据模型：

Java代码

1.@Table(name="nodes")

2.public class Node extends ActiveRecordBase{

3.@Id public Integer id;

4.@Column public Integer parentId;

5.@Column public String name;

6.

7.public boolean hasChildren() throws Exception{

8.long count = count(Node.class, "parentId=?", new Object[]{id});

9.return count > 0;

10. }

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11.}

编写后台的控制器代码：

Java代码

1.public class NodeController extends ApplicationController{

2./**

3. * get nodes, if the 'id' parameter equals 0 then load the first level nodes,

4. * otherwise load the children nodes

5. * @param id the parent node id value

6. * @return the tree required node json format

7. * @throws Exception

8. */

9.public View getNodes(int id) throws Exception{

10. List nodes = null;

11.

12.if (id == 0){ // return the first level nodes

13. nodes = Node.findAll(Node.class, "parentId=0 or parentId is null", null);

14. } else { // return the children nodes

15. nodes = Node.findAll(Node.class, "parentId=?", new Object[]{id});

16. }

17.

18. List> items = new ArrayList>();

19.for(Node node: nodes){

20. Map item = new HashMap();

21. item.put("id", node.id);

22. item.put("text", https://www.360docs.net/doc/5211068905.html,);

23.

24.// the node has children,

25.// set the state to 'closed' so the node can asynchronous load children nodes

26.if (node.hasChildren()){

27. item.put("state", "closed");

28. }

29. items.add(item);

30. }

31.

32.return new JsonView(items);

33. }

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34.}

运行测试程序：http://localhost:8080/demo2/

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