@RequestMapping(value = "/tree")
 public void tree(HttpServletRequest request, HttpServletResponse response) throws IOException {
  this.writeJson(response, bookService.getTree());
 }

 /**
  * 獲取樹
  */
 @Override
 public List<Tree> getTree(){
  try {
   List<Tree> trees = new ArrayList<Tree>();
   List<TBookType> root = this.search(0);
   if(root != null && root.size() > 0){
    for(TBookType tb : root){
     Tree rootnode = this.getNode(tb);
     rootnode.setState("open");
     trees.add(rootnode);
    }
   }
   return trees;
  } catch (Exception e) {
   e.printStackTrace();
   return null;
  }
 }
 /**
  * 遞歸
  */
 private Tree getNode(TBookType node){
  if(node == null){
   return null;
  }
  try {
   Tree treenode = new Tree();
   treenode.setId(String.valueOf(node.getId()));
   treenode.setText(node.getName());
   treenode.setPid(String.valueOf(node.getPid()));
   List<TBookType> children = this.search(node.getId());
   if(children != null && children.size() > 0){
    treenode.setState("closed");
    for(TBookType child : children){
     Tree childnode = this.getNode(child);
     if(childnode != null){
      treenode.getChildren().add(childnode);//遞歸
     }
    }
   }
   return treenode;
  } catch (Exception e) {
   throw new BusinessException("獲取數據出錯!", e);
  }
 }