JavaScript Ajax Json realizes the linkage effect of upper and lower drop-down boxes example code_javascript skills

I recently tried to create a drop-down box linkage function between departments and personnel. The corresponding relationship between departments and personnel is 1:N

Copy code The code is as follows:

Department< ;/div>

Please select

People

The onchange() event of the department drop-down box takes an AJAX method and returns a JSON object (the JSON contains a LIST).

How to write js method on this page:

Copy code The code is as follows:

The data returned here contains a list (see list below). The list contains two attributes: the person's code and the person's name. Then empty() the personnel drop-down box first, and add a new drop-down box element through the select control append method.

Backend code:

Copy code

The code is as follows:

public String departmentChangeEvent() throws Exception{
  userList=service.queryForList("Workorder.queryUserByDepartmentCode", departmentCode);
  if(userList!=null&&userList.size()>0)
  {
   HttpServletResponse response = ServletActionContext.getResponse();
   response.setContentType("text/html;charset=utf-8");
   response.setHeader("Pragma","No-cache");
   response.setHeader("Cache-Control","no-cache");
   response.setHeader("Cache-Control", "no-store");
   PrintWriter writer = response.getWriter();
   JSONObject json = new JSONObject();
   Map map = new HashMap();
      map.put("list",userList);
      JSONObject jso = JSONObject.fromObject(map);
   writer.write(jso.toString());
      writer.flush();
      writer.close();  }
         return null; 
   } 

这个方法是部门切换事件，通过departmentCode(field域，有set,get)来求的当前部门下的用户放到userList中。

然后通过标准写法把userList放到一个定义好的HashMap中，KEY为list。

复制代码 代码如下:

JSONObject jso = JSONObject.fromObject(map); 

这是最为关键的一步，有的json对象创建方法也可以为JSONObject jso = new JSONObject() ； 然后把list里的记录放入到jso中。。。

在这里是行不通的，前台会认为返回的是个字符串。。。

struts中 返回类型为json

复制代码 代码如下:

 
      
    
       

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