遍历hashmap

List dataList = VirtualDataGenerator.getVirtualResult();    
    
  // 节点列表（散列表，用于临时存储节点对象）  
  HashMap nodeList = new HashMap();  
  // 根节点  
  Node root = null;  
  // 根据结果集构造节点列表（存入散列表）  
  for (Iterator it = dataList.iterator(); it.hasNext();) {  
   Map dataRecord = (Map) it.next();  
   Node node = new Node();  
   node.id = (String) dataRecord.get("id");  
   node.text = (String) dataRecord.get("text");  
   node.parentId = (String) dataRecord.get("parentId");  
   nodeList.put(node.id, node);  
  }  
  // 构造无序的多叉树  
  Set entrySet = nodeList.entrySet();  
  for (Iterator it = entrySet.iterator(); it.hasNext();) {  
   Node node = (Node) ((Map.Entry) it.next()).getValue();  
   if (node.parentId == null || node.parentId.equals("")) {  
    root = node;  
   } else {  
    ((Node) nodeList.get(node.parentId)).addChild(node);  
   }  
  }