关于Ajax中通过response在后台传递数据问题

var System = { 
 getHttpRequest: function(url, callback, options) { 
 if (url.length < 0) return; 
 var option = { 
 url: url, 
 type: "get", 
 dataType: "json", 
 cache: false, 
 timeout: 30000, 
 beforeSend: function(XHR) { 
 }, 
 complete: function(XHR, textStatus) { 
 XHR.abort(); 
 }, 
 error: function(XMLHttpRequest, textStatus, errorThrown) { 
 //alert("网络连接不通，请稍后再试！"); 
 }, 
 success: function(data) { 
 callback(data, options); 
 } 
 }; 
 if ( !! options) { 
 option = $.extend(option, options); 
 } 
 $.ajax(option); 
 } 
}; 

public String getRejectReason() throws Exception{ 
 String rowId = getParameterAndPut("rowId",null,0).toString(); 
 String jsonData = ""; 
 if (StringUtils.isNotEmpty(rowId)) { 
 jsonData = newOwnerInfoService.getRejectReasonJsonData(rowId); 
 } 
 this.getResponse().setCharacterEncoding("utf-8"); 
 this.getResponse().getWriter().write(jsonData); 
 return null; 
}