Ext.tree.panel 后端动态加载json数据

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首先建一个bean类，如：

package ***.bean;

import java.io.Serializable;
import java.util.List;

public class Menu implements Serializable {

 private static final long serialVersionUID = 1L;
 private String id;
 private String parentId;//设置父id和子id用来拼接children，设成字符串有利于自主生成
 private String a;
 private String b;

..........//设置自己需要传到前端的变量
 private boolean leaf;
 private boolean expanded;
 private List<Menu> children;
 
 public String getId() {
  return id;
 }
 public void setId(String id) {
  this.id = id;
 }
 public String getParentId() {
  return parentId;
 }
 public void setParentId(String parentId) {
  this.parentId = parentId;
 }
 public List<Menu> getChildren() {
  return children;
 }
 public void setChildren(List<Menu> children) {
  this.children = children;
 }
 public boolean isExpanded() {
  return expanded;
 }
 public void setExpanded(boolean expanded) {
  this.expanded = expanded;
 }
 public boolean isLeaf() {
  return leaf;
 }
 public void setLeaf(boolean leaf) {
  this.leaf = leaf;
 }

}

在service层把dao层查出来的数据拼接

List<String> areaList = dao.getNameList();
 Iterator<String> strIter = areaList.iterator();
  List<Menu> subMenus = new ArrayList<Menu>();
  while(strIter.hasNext()){
   String key = strIter.next();
   Menu menu = new Menu();
   menu.setLeaf(false);
   menu.setExpanded(false);
   menu.setId(key);
   menu.setParentId("-1");
     try {
   　　 menu.setChildren(this.fanfa(areaTimeHglMap,start_time,end_time,key,selecttype));
   } catch (ParseException e) {
   　　 e.printStackTrace();
   　　 menu.setChildren(null);
   }
  　　 subMenus.add(menu);
  }  

在action层传给前端就可以了

balanceStatistics = service.getBusBalanceStatistics(start_time, end_time, areaID, selecttype,areaName);
   JSONObject jsonObject = new JSONObject();
   jsonObject.put("children", balanceStatistics);
   retValue = jsonObject.toString(); 

！注意： 这里的名称要写children因为前端是默认不显示根节点的

前端treepanel数据源：

var treeStore = Ext.create(‘Ext.data.TreeStore‘, {
    model: ‘Task‘,
    proxy: {
        type: ‘ajax‘,
        url: getBusBalanceStatisticsURL,
        reader: {
            type: ‘json‘,
            root : "children"
        }
    },
    fields: ["id",  "parentid", "city"],
    folderSort: true
});

就可以得到想要的树状图统计表：

Ext.tree.panel 后端动态加载json数据

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原文地址：http://www.cnblogs.com/lf90/p/5073357.html