JS unlimited navigation menu implementation method

private int id; //id
  private String dept_name;  //Department name  private int pid;  //The superior department id  private int sort_num;  //Sort values  private int create_id; //Create  private String create_time; //Creation time  private int modify_id; //Modify  private String modify_time; //Last modified time  private int is_del; // Whether to delete 0 Not deleted 1 Deleted  private int status; //status
  private String remark; //remark
  private List<Dept> deptChild = new ArrayList<>(); //Department iteration

List<Dept> selectDeptForJsonMenu();

<resultMap type="" >
    <result column="id" property="id" javaType="" />
    <result column="dept_name" property="dept_name" javaType="" />
    <result column="sort_num" property="sort_num" javaType="" />
    <result column="create_time" property="create_time" javaType="" />
    <result column="modify_id" property="modify_id" javaType="" />
    <result column="modify_time" property="modify_time" javaType="" />
    <result column="is_del" property="is_del" javaType="" />
    <result column="status" property="status" javaType="" />
    <result column="remark" property="remark" javaType="" />
    <collection column="id" property="deptChild" javaType="" select="selectDeptForJsonMenuChild"/>
  </resultMap>
  <!-- Query department menu tree -->
  <select  resultMap="deptFirst">
    SELECT * FROM sys_dept WHERE pid = 0 AND is_del = 0 ORDER BY sort_num
  </select>
  <select  resultMap="deptFirst" parameterType="">
    select * FROM sys_dept where pid = #{id} AND is_del = 0 ORDER BY sort_num
  </select>

public List<Dept> selectDeptForJsonMenu(){
    return ();
  }

@RequestMapping(value = "selectDeptForJsonMenu",method={,})
  @ResponseBody
  public List<Dept> selectDeptForJsonMenu(){
    return ();
  }

<div >
</div>

$(function(){
  $.ajax({
    method:'post',
    url:getPath+"dept/selectDeptForJsonMenu",
    dataType:'json',
    success:function(data){
      if( > 0){
        var showlist = $('<ul class="layui-nav layui-nav-tree"></ul>');
        showall(data, showlist);
        $("#leftMenu").html(showlist);
      }else{ 
        $('#leftMenu').html('<span class="layui-btn layui-btn-primary" >Add</span>') ;      }
    }
  });
  //json is json data  //parent is the final html splicing content  function showall(json, parent) {
    for (var i in json) {
      //There are child nodes traversal      if (json[i]. &gt; 0) {
        //Create li        var li = $('&lt;li class="layui-nav-item layui-nav-itemed"&gt;&lt;/li&gt;');
        $(li).append('&lt;a href="javascript:;" rel="external nofollow" rel="external nofollow" &gt;'+json[i].dept_name+'&lt;/a&gt;');
        $(li).append('&lt;ul class="layui-nav-child"&gt;&lt;/ul&gt;').appendTo(parent);
        //Select UL Callback        showall(json[i].deptChild, $(li).children().eq(1));
      }
      //No children      else {
        $('&lt;li&gt;&lt;/li&gt;').append('&lt;a href="javascript:;" rel="external nofollow" rel="external nofollow" &gt;'+json[i].dept_name+'&lt;/a&gt;').appendTo(parent);
      }
    }
  }
});