js gets the method of JSONArray of the map type returned by ajax

for(var i in datares){ 
if (datares.hasOwnProperty(i)) { 
sel.append("<option value='"+datares[i].deptid+"'>"+datares[i].deptname+"</option>"); 
} 

} 

ajax requests a map back and traverses it

$.ajax({
       type: "POST",
url: "<%=path%>/account/queryRolesAndGroups.action",
data: "enterpriseId="+eid,
success: function(msg){
var obj=eval("(" + msg + ")");
$.each(obj.groupList, function(i,item){      
alert(item.groupName); 
  })
}
})  
})

Send a request to the background, and then the background through a variety of operations, to get the corresponding data

If the data is map, map contains more than one list,

pw.print(net.sf.json.JSONObject.fromObject(returnMap.get("map")).toString());

The background is converted like this, and then the fore desk is converted: var obj=eval ("""

You can traverse the data inside (note: net.sf.json.JSONArray.fromObject ("list") so that it applies when converting a single collection, and then the fore desk traverses directly, without the need for a strong turn

success: function(msg){
alert（msg.length）;
$.each(msg, function(i,item){      
alert(item.name); 
   })
}

JSONArray applies when turning a map that contains multiple lists.

There is also the use of background pw.print and pw.println should also note that when a single data 0,1 to the background judgment, pw.println will bring line breaks, never equal to 0,1.

response.setContentType("text/plain;charset=UTF-8");
     PrintWriter pw =response.getWriter();

These two sentences should also pay special attention to the order of return garbled processing.

PrintWriter pw =response.getWriter(); In the first words, the conversion also does not work!