jQuery在请求后发送表单数据，但是当我修改servlet以返回json并修改jQuery以接受json servlet时未收到null

Question

My im sending jquery to a servlet and try to connect with db. it is working good. But when I try to return json from servlet and modify jsp to accept json type. the parameters received by servlet are null why?? Waiting for the solution...

Here is my code:

function submitData()
{
    alert('Called');
    $('document').ready(function(){
        $.ajax({
            url:'/DashBoard/FetchAlerts',  
            type:'post',
            dataType:'json',
            data: $('#dataForm').serialize(),
            cache: false,
            contentType: 'application/json',
            success: function(data) {
                alert('Yes!');
                $.each(data.obj,function(index,obj)
                        {
                    alert('Date:'+obj.date+'Hour:'+obj.hours);
                    })
            } 
            });
    });
}

if i remove lines datatype and contentType or set contentType to application/www-x-urlencoded servlet is receiving parameters.

Here is my servlet code:

 response.setContentType("application/json"); int startHour,startMinute,endHour,endMinute; String temp[]; Calendar cal; out=response.getWriter(); System.out.println("Url Called"); String startDate=request.getParameter("startDate"); System.out.println(request.getParameter("startDate")); System.out.println(request.getAttribute("startDate")); Timestamp startTDate,endTDate; if(startDate==null||startDate.trim().isEmpty()) { startDate=new Date()+""; } String endDate=request.getParameter("endDate"); if(endDate==null||endDate.trim().isEmpty()) { endDate=new Date()+""; } String color=request.getParameter("color"); if(color==null||color.trim().isEmpty()) { color="Red"; } String startTime=request.getParameter("startTime"); if(startTime==null||startTime.trim().isEmpty()) { startTime=new Date().getTime()+""; } temp=startTime.split(" "); temp=temp[0].split(":"); try{ startHour=Integer.parseInt(temp[0]); }catch(NumberFormatException ne){ startHour=0; } if(startHour+""=="12") startMinute=Integer.parseInt(temp[1]); else startMinute=Integer.parseInt(temp[1])+12; String endTime=request.getParameter("endTime"); if(endTime==null||endTime.trim().isEmpty()) { endTime=new Date().getTime()+""; } temp=endTime.split(" "); temp=temp[0].split(":"); try{ endHour=Integer.parseInt(temp[0]); }catch(NumberFormatException ne){ endHour=0; } if(endHour+""=="12") endMinute=0; else endMinute=Integer.parseInt(temp[1]); String searchText=request.getParameter("searchTextBox"); if(searchText.trim().isEmpty()) { searchText=""; } String radio1=request.getParameter("radio1"); if(radio1.trim().isEmpty()) { radio1="All"; } System.out.println("Status:"+radio1); try{ SimpleDateFormat from=new SimpleDateFormat("MM/dd/yyyy"); SimpleDateFormat to=new SimpleDateFormat("yyyy-MM-dd"); Date date=from.parse(startDate); System.out.println("Date:"+date); startDate=to.format(date); cal=GregorianCalendar.getInstance(); cal.set(Calendar.DATE, date.getDate()); cal.set(Calendar.MONTH, date.getMonth()); cal.set(Calendar.YEAR, date.getYear()+1900); cal.set(Calendar.HOUR, date.getHours()); cal.set(Calendar.MINUTE, date.getMinutes()); startTDate=new Timestamp(cal.getTimeInMillis()); date=from.parse(endDate); System.out.println("Date1:"+date); cal=GregorianCalendar.getInstance(); cal.set(Calendar.DATE, date.getDate()); cal.set(Calendar.MONTH, date.getMonth()); cal.set(Calendar.YEAR, date.getYear()+1900); cal.set(Calendar.HOUR, date.getHours()); cal.set(Calendar.MINUTE, date.getMinutes()); endTDate=new Timestamp(cal.getTimeInMillis()); endDate=to.format(date); sql="select * from alerts where Date BETWEEN '"+startTDate+"' AND '"+endTDate+"' AND color='"+color+"'AND Status='"+radio1+"'"; } catch(ParseException p){ } catch(NullPointerException ne){ } try{ Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection(DB_URL,USER,PASS); stmt=conn.createStatement(); rs=stmt.executeQuery(sql); JSONObject json=new JSONObject(); JSONArray obj; obj=new JSONArray(); while(rs.next()){ JSONObject ob1=new JSONObject(); Timestamp tem=rs.getTimestamp("Date"); SimpleDateFormat s1=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); try{ Date d1=s1.parse(tem+""); int hour=d1.getHours(); int min=d1.getMinutes(); s1=new SimpleDateFormat("dd-MM-yyyy"); ob1.put("Date", d1); ob1.put("Hours",hour); ob1.put("Minutes",min); ob1.put("Status", rs.getString("Status")); ob1.put("Color",rs.getString("Color")); ob1.put("Description", rs.getString("Description")); }catch(ParseException p){ } catch(JSONException je){ } } json.put("obj", obj); out.print(json); rs.close(); stmt.close(); conn.close(); } catch(SQLException sq){ } catch(ClassNotFoundException ce){ } catch(JSONException je){ } 

Answer 1

我找到了解决方案的人...我用此应用程序/ x-www-form-urlencoded替换了内容类型，它现在正在工作...谢谢