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; 
}