jstree 主页 :
http://www.jstree.com/

其中提供了一种从后台取数据渲染成树的形式：

 $("#mytree").tree({
      data  : {
        type  : "json",
        url : "${ctx}/user/power!list.do"
      }
});

对于url中返回的值必须是它定义的json数据形式:

$("#demo2").tree({
  data  : {
    type  : "json",
    json  : [ 
      { attributes: { id : "pjson_1" }, state: "open", data: "Root node 1", children : [
        { attributes: { id : "pjson_2" }, data: { title : "Custom icon", icon : "../media/images/ok.png" } },
        { attributes: { id : "pjson_3" }, data: "Child node 2" },
        { attributes: { id : "pjson_4" }, data: "Some other child node" }
      ]}, 
      { attributes: { id : "pjson_5" }, data: "Root node 2" } 
    ]
  }
});

这里需要一个从后台实例集合转换为它规定的json数据的形式.

/**
     * 无限递归获得jsTree的json字串
     * 
     * @param parentId
     *            父权限id
     * @return
     */
    private String getJson(long parentId)
    {
        // 把顶层的查出来
        List<Action> actions = actionManager.queryByParentId(parentId);
        for (int i = 0; i < actions.size(); i++)
        {
            Action a = actions.get(i);
            // 有子节点
            if (a.getIshaschild() == 1)
            {
                str += "{attributes:{id:\"" + a.getAnid()
                        + "\"},state:\"open\",data:\"" + a.getAnname() + "\" ,";
                str += "children:[";
                // 查出它的子节点
                List<Action> list = actionManager.queryByParentId(a.getAnid());
                // 遍历它的子节点
                for (int j = 0; j < list.size(); j++)
                {
                    Action ac = list.get(j);
                    //还有子节点(递归调用)
                    if (ac.getIshaschild() == 1)
                    {
                        this.getJson(ac.getParentid());
                    }
                    else
                    {

                        str += "{attributes:{id:\"" + ac.getAnid()
                                + "\"},state:\"open\",data:\"" + ac.getAnname()
                                + "\" " + "   }";
                        if (j < list.size() - 1)
                        {
                            str += ",";
                        }
                    }
                }
                str += "]";
                str += "   }";
                if (i < actions.size() - 1)
                {
                    str += ",";
                }
            }
        }
        return str;
    }

调用:

@org.apache.struts2.convention.annotation.Action(results =
    { @Result(name = "success", location = "/main/user/action-list.jsp") })
    public String list()
    {
        String str = "[";
        // 从根开始
        str += this.getJson(0);
        str += "]";
        this.renderJson(str);
        return null;
    }

其中Action是菜单类或权限类等的实体。
效果图: