请问如何实现tree的右键菜单??

//右键点击事件    jPopupMenu = new JPopupMenu();
    JMenuItem item1 = new JMenuItem("添加子节点");
    JMenuItem item2 = new JMenuItem("编辑节点");
    JMenuItem item3 = new JMenuItem("删除节点");    jPopupMenu.add(item1);
    jPopupMenu.add(item2);
    jPopupMenu.add(item3);    item1.addActionListener(new ActionListener() {
      public void actionPerformed(ActionEvent ae) {
        addNode();
      }
    });
tree.add(jPopupMenu);
    tree.addMouseListener(new MouseAdapter() {
      public void mouseReleased(MouseEvent er) {
        try {
          //是否右键单击
          if (er.getClickCount() == 1 && SwingUtilities.isRightMouseButton(er)) {
            TreePath path = tree.getPathForLocation(er.getX(), er.getY());
            if (path == null)
              return;
            tree.setSelectionPath(path);
            jPopupMenu.show(tree, er.getX(), er.getY());
          }          else if (er.getClickCount() == 1) {
            TreePath path = tree.getPathForLocation(er.getX(), er.getY());
            if (path == null)
              return;
            if (tree.isExpanded(path)) {
              tree.collapsePath(path);
            }
            else {
              tree.expandPath(path);
            }
            return;
          }
        }
        catch (Exception ex) {
          ex.printStackTrace();
        }
      }
    });