Spring MVC cannot get the parameters and values of Ajax post

How can it be this way

A very simple idea, Ajax submits a form in post, Spring MVC parsing. Yet again and again the printing of NULL tortured me for a whole day ...

The final Solution now appears to be a clear question, "just disconsolate" ...

It is boundless! It is boundless! It is boundless!

Second, simple original sin

Ajax commits the following code:

1<script type="Text/javascript">2 $ (document). Ready (function () {3$("#submit"). Click (function (e) {4 E.preventdefault ();5         varobj = $ ( This);6         varName = $ ("input[name= ' name ']"). Val ();7         varPhone = $ ("input[name= ' phone ']"). Val ();8 $.ajax ({9Url:"Userask",TenType:"POST", OneContentType:"Application/json;charset=utf-8", A data: {Name:name,phone:phone}, -           //dataType: "Text", - success:function (result, status, req) { the$(". Noticeinfo"). CSS ("Display","Block"); -           }, - error:function (req, status, reason) { -$(". Noticeinfo"). CSS ("Display","Block"). Text ('Error:'+reason); +           } -         }) +         return false; A       }) at     }); -</script>

Third, the tangled backstage

By the way, review the values of Spring MVC:

1. Get the value in the URL by annotating pathvariable.

1  @RequestMapping (value="user/{id}/{name}", method=requestmethod.get)2 public    string Mycontroller (@PathVariable string ID, @PathVariable string name, Modelmap model) { /c9>3      ... 4      return " OK " ; 5  }

2. Get the value passed through the annotation requestparam.

1@RequestMapping (value ="/test", method =requestmethod.post)2  PublicString MyTest (@RequestParam ("name") String name, @RequestParam ("Phone") String phone, modelmap model) {3 ...4     return "OK";5}

3. Use the source httpservletrequest to get the value yourself.

1@RequestMapping (value="/test"METHOD =requestmethod.post)2  PublicStringGet(HttpServletRequest request, httpservletresponse response) {3String name = Request.getparameter ("name")); 4     return "OK"; 5}

4. Use annotations to modelattribute the parameters in the form directly to Pojo.

Note: For the time being, I use JSON to serialize the situation.

The above method I tried various, has been ruthless print null.

Four, do you suspect that the background has received data?

1 bufferedreader BR;2         Try {3BR =Req.getreader ();4String str, wholestr ="";5              while(str = br.readline ())! =NULL){6Wholestr + =str;7             }8System. out. println (WHOLESTR);9}Catch(IOException e) {Ten e.printstacktrace (); One}

The printed string is identical to the data sent by the front end ...

Five, the final truth ...

I used the most primitive method to re-write an identical form, which was submitted using the form without Ajax. The background can print out the data!

Compared with two front-end HTTP request data, modified the data format of AJAX submission, resolved:

1 " application/x-www-form-urlencoded ",

That is: When an AJAX request is received, Spring MVC resolves the received request in JSON format, based on the data type indication.

But it seems name=lings&phone=13899999999 this string submitted in form data format does not match JSON parsing.

Once the data type is re-indicated, the above method of fetching is feasible.

Spring MVC cannot get the parameters and values of Ajax post