用ajax上传文件

//上传文件，在action中
 public void loadfile(){
  try{
   JSONObject json = new JSONObject();
   String gameName = g_packagepath.substring(g_packagepath.lastIndexOf("."));
   String newgameName = request.getRealPath("/")+"/ifreame/resource/images/"+g_gamename+ gameName;
   //路径格式转换统一格式
   File newgame_name = new File(newgameName);
   String newFileGameName = newgame_name.getCanonicalPath();
   //调用文件上传工具类
   if (UploadUtils.uploadFile(g_packagepath, newFileGameName, 1024*1024)) {
    // success
    request.setAttribute("msg", "图片上传成功!");
   } else {
    // fail
    request.setAttribute("msg", "图片上传失败!");
   }
   //页面上获取值时给json  put值
   json.put("newFileGameName", newFileGameName);
   response.getWriter().print(json);
   }catch(Exception e){
    e.printStackTrace();
   }
 }

界面上

$('#loadfile').click(
     function() {

$.ajax( {
       type : "post",
       url : "${pageContext.request.contextPath}/gamemanage!loadfile.action",
       data : {
        'g_gamename'  : $('#g_gamename').val(),
        'g_packagepath' : $('#g_packagepath').val()
       },
       dataType : "json",
       success : function(msg) {
       alert(msg.newFileGameName)
         $('#hiddengame').val(msg.newFileGameName);
        
       }
     });

   });

//界面中的demo

<tr>
     <td id="packagepath">游戏文件路径：</td>
     <td><input type="file"  name="g_packagepath" id="g_packagepath" />
     </td>
     
     <td><input type="button" value="上传文件" id="loadfile"/>
          </td>
     
    </tr>
    
    <tr>
    <td>
    <input type="text" id="hiddengame"  name="hiddengame" /></td>
    </tr>