send json data from ajax and parse in servlet - javascript

Hi I am a newbie in servlet and trying to send object from javascript to servlet using ajax. javascript code looks like this:
$.ajax({
url:'GetUserServlet',
contentType: "application/json",
data: JSON.stringify(response),
type:'post',
cache:false,
success:function(data){
//alert(data);
$('#somediv').text("user info sent successfully");
},
error:function(){
$('#somediv').text("some error occured");
}
}
);
Here response is object received from facebook api. It is:
reponse={ first_name: "Jhon", last_name: "Doe", id: "19862217575855" }
The doPost method of GetUserServlet is defined as:
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Gson gson = new Gson();
User user = gson.fromJson(request.getParameter(response), User.class);
System.out.println(user);
}
User.class is another class containing getter and setter for first_name, last_name and id
But the program is not getting compiled. I have used many syntax changes but cannot find the correct value. How can i get the response object inside servlet?

// 1. get received JSON data from request
BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));
String json = "";
if(br != null){
json = br.readLine();
}
// 2. initiate jackson mapper
ObjectMapper mapper = new ObjectMapper();
// 3. Convert received JSON to User
User user = mapper.readValue(json, User.class);
// 4. Set response type to JSON
response.setContentType("application/json");
System.out.println("..user.." + user);

Related

Ajax post request in Spring MVC

I am currently trying to call an ajax request from a JavaScript onchange handler to call a Spring MVC controller. I believe the way I am currently calling the URL in my view is wrong since I get an 404 error on the browser when the event is triggered and call for url. Can anyone shine some light if I have everything setup correctly?
Here is my code:
#Controller
public class DataTableController
{
#RequestMapping(value = "/table", method = RequestMethod.GET)
public String home(Model model) throws JsonGenerationException, JsonMappingException, IOException
{
List<String> gpnList = new ArrayList<GPN>();
gpnList.add("GPN-1"); gpnList.add("GPN-2"); gpnList.add("GPN-3");
model.addAttribute("gpnList", mapper.writeValueAsString(gpnList));
return "index"; //name of my view
}
#RequestMapping(value = "/getsector", method = RequestMethod.POST)
public #ResponseBody String getSector(#RequestParam("market")String market) throws JsonGenerationException, JsonMappingException, IOException
{
List<String> sectors = new ArrayList<String>();
sectors.add("Auto"); sectors.add("Industrial"); sectors.add("Analog");
ObjectMapper mapper = new ObjectMapper();
return mapper.writeValueAsString(sectors);
}
}
Jquery Code:
$(document).ready(function()
{
document.getElementById("markets").onchange = function()
{
var market = $("select[id='markets'").find('option:selected').text();
var filters = { "market" : market }
filters = JSON.stringify(filters);
$.ajax({
url: "/getsector",
type: "POST",
dataType : 'json',
contentType : "application/json",
data: JSON.stringify(filters),
success: function(response)
{
console.log("sucess!");
},
error: function(e){
console.log("ERROR: ", e);
}
});
}
});
The main thing I want to achieve is being able to call my controllers via ajax calls. Any other tips on Spring Controller Mapping and conventions will be appreciated.
If your a requesting information you should use GET requests, not POST.
You are mixing #RequestParam with a json payload. If you want to receive your filter as a request param it has to go at the url, not as a json payload, using something like:
$(document).ready(function()
{
document.getElementById("markets").onchange = function()
{
var market = $("select[id='markets'").find('option:selected').text();
$.ajax({
url: "/getsector?market="+market,
type: "GET",
success: function(response)
{
console.log("sucess!");
},
error: function(e){
console.log("ERROR: ", e);
}
});
}
});
#RequestMapping(value = "/getsector", method = RequestMethod.GET)
public #ResponseBody String getSector(#RequestParam("market")String market) throws JsonGenerationException, JsonMappingException, IOException
{
.... your logic.
}
On the other hand, if you really want to use POST requests with a json payload, you need to use #RequestBody at the controller and bind the json object to a bean with the same properties.
#RequestMapping(value = "/getsector", method = RequestMethod.POST)
public #ResponseBody String getSector(#RequestBody Market market) throws JsonGenerationException, JsonMappingException, IOException
{
List<String> sectors = new ArrayList<String>();
sectors.add("Auto"); sectors.add("Industrial"); sectors.add("Analog");
return sectors;
}
public class Market
{
String market;
//getter and setter...
}
Bear in mind your javascript is wrong as well, you are using JSON.stringify twice.
If you use #ResponseBody and spring is configured fine it will make the serialisation for you when returning the response, so you do not have to do it manually.
This code has not been tested, it is just for you to get an idea.

Passing Json object from java script to java

I am new to springs and ajax
I am having a json object in my java script which is created dynamically
I need to send this json object from java script using ajax or normal submit()
If it is a string we have hidden inputs.
as of my knowledge if I am not wrong
a JSON object we cannot store it in hidden
And I have to receive using java code.
This is my script
$(document).ready(function(){
// click on button submit
$("#save_btn").on('click', function(){
alert();
// send ajax
$.ajax({
url: 'project_reg_save', // url where to submit the request
type : "POST", // type of action POST || GET
dataType : 'json', // data type
data : $("#reg_form").serialize(), // post data || get data
success : function(result) {
// you can see the result from the console
// tab of the developer tools
console.log(result);
},
error: function(xhr, resp, text) {
console.log(xhr, resp, text);
}
})
});
});
and this is my java code
#Controller
public class Save {
#RequestMapping("/project_reg_save")
public ModelAndView mymethod(#RequestParam JSONObject obj)//which is not possible {
System.out.println(obj);
return new ModelAndView("Product_reg", "msg", "product Registration");
}
}
One solution is to
change your dataType : 'json' to dataType : 'text'
#RequestParam JSONObject obj to #RequestParam String obj
JsonObject JsonObj= new JsonParser().parse(obj).getAsJsonObject();
hence you get json object

how to reply to ajax post using servlet [duplicate]

This question already has answers here:
How should I use servlets and Ajax?
(7 answers)
Closed 6 years ago.
i have a username textbox that when a user input a name it takes that name and send to server and the server check if the username has not been taken by anybody else, if so i need to send back somedata and tell the client that the username has been taken else if it is not i need to turn the textbox border color to green, now i can do sending username value to server but i don't know how to send back and how to receive the sent data using jquery ajax.
here is my code:
client:
$(document).ready(function() {
$('#Registeration_Username_box').on('input', function() {
postUsernameToServer();
});
function postUsernameToServer() {
var formData = {
'username': $('input[name=UserName]').val(),
};
// process the form
$.ajax({
type: 'POST', // define the type of HTTP verb we want to use (POST for our form)
url: '../dusernameavailable', // the url where we want to POST
data: formData, // our data object
dataType: 'json', // what type of data do we expect back from the server
encode: true
}).done(function(data) {
console.log(data);
});
}
});
servlet:
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
String str = request.getReader().lines().collect(Collectors.joining(System.lineSeparator()));
System.out.println(str);
}
Add success and error to your ajax
function postUsernameToServer() {
var formData = {
'username': $('input[name=UserName]').val(),
};
// process the form
$.ajax({
type: 'POST', // define the type of HTTP verb we want to use (POST for our form)
url: '../dusernameavailable', // the url where we want to POST
data: formData, // our data object
dataType: 'json', // what type of data do we expect back from the server
encode: true,
success: function(data) {
//TODO make the box green or whatever your requirement is
},
error: function() {
//TODO username already taken
}
});
}
});
In servlet send appropriate response.
You will need to send a response code other than 200 for ajax to consider it as an error from the server.
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String str = request.getReader().lines().collect(Collectors.joining(System.lineSeparator()));
System.out.println(str);
//TODO - check if user name exists or not
if(user name already exists){
response.setProperty(response.HTTP_STATUS_CODE, "500");
PrintWriter out = response.getWriter();
out.println("error");
out.close();
}
else{
PrintWriter out = response.getWriter();
out.println("success");
out.close();
}
}
}
Add a success handler to your ajax call.
You can try something like below; where 'green' and 'red' are css classes you defined in your CSS file .
$.ajax({
type: 'POST', // define the type of HTTP verb we want to use (POST for our form)
url: '../dusernameavailable', // the url where we want to POST
data: formData, // our data object
dataType: 'json', // what type of data do we expect back from the server
encode: true,
success: function(response) {
if(response.isUserNameAvailable == true)
$('input[name=UserName]').addClass('green');
else
$('input[name=UserName]').addClass('red');
}
}).done(function(data) {
console.log(data);
});

Attempts to use an ajax call to the controller to insert search results into a table result in errors

Longer title would be:
"Attempts to use an ajax call to the controller to insert search results into a table result in errors while remaining on the same page results in "405" or "Direct self-reference leading to cycle... " errors"
I am trying to find a way to fill a table with search result while staying on same page using an ajax call to the controller.
ajaxCall->Controller->Service(completes search)->Controller(result from search)->back to ajax with response
I have an ajax call that is triggered on form submit after prevent default:
function ajaxGetSearchResults(link, form) {
var myList=[];
var jqxhr = $.ajax({
"url" : link,
"data" : form.serialize(),
"dataType" : 'json',
"type" : "POST",
"headers": {
'Content-Type': 'application/json'
},
"success" : function (response){
console.log("Ajax success");
fillTable(response);
console.log("Search results added to table: "+response);
},
"complete": function(response){
console.log("Ajax call to controller completed");
},
"error": function(){
console.log("Ajax call to controller triggered error");
}
});
}
In the controller I recieve the ajax request as such:
#RequestMapping(value = "/ajaxScriptSearch", method = RequestMethod.POST)
public #ResponseBody List<ResultViewDto> processAJAXRequestSearch(#RequestParam String a1,
#RequestParam String a2, #RequestParam String a3, #RequestParam String a4) {
SearchDto searchDto = new SearchDto();
searchDto.setAttribute1(a1);
searchDto.setAttribute2(a2);
searchDto.setAttribute3(a3);
searchDto.setAttribute4(a4);
try {
/*
calling Service, performing search using searchDto as a parameter, mapping result to resultViewDtos
*/
} catch(Exception e){
/* do something */
}
return resultViewDtos;
}
The call to the service is successfull.
An example of resultViewDtos would be: [viewDto1, viewDto2, viewDto3] where every view dto contains a number of string values which need to be inserted into a table.
I seem to be getting a "HTTP Status 405 - Request method 'GET' not supported" error, but my ajax call is "type: POST".
When I tried doing it with GET insted, I get an "Direct self-reference leading to cycle (through reference chain...)" error.
I am using jackson-core 2.6.2, jackson-databind 2.6.2, Spring 4, Hibernate 4.
I would appericiate any help I can get...
In the end I managed to create a workaround for this.
I have changed my ajax call as such:
function ajaxGetSearchResults(link, form) {
var jqxhr = $.ajax({
"url" : link,
"data" : form,
"dataType" : 'json',
"headers": {
'Accept' : 'application/json',
'Content-Type': 'application/json'
},
"type" : "GET",
"success" : function (response) {
console.log("Ajax success");
fillTable(response);
},
"complete": function(response) {
console.log("Ajax call to controller completed");
},
"error": function() {
console.log("Ajax call to controller triggered error");
}
});
}
And my controller as follows:
#RequestMapping(value = "/ajaxScriptSearch", method = RequestMethod.GET)
public #ResponseBody List<String> processAJAXRequestSearch(#RequestParam String a1,
#RequestParam String a2, #RequestParam String a3, #RequestParam String a4) {
SearchDto searchDto = new SearchDto();
searchDto.setAttribute1(a1);
searchDto.setAttribute2(a2);
searchDto.setAttribute3(a3);
searchDto.setAttribute4(a4);
List<String> result = new ArrayList<String>();
List<ResultViewDto> resultViewDtos = new ArrayList<ResultViewDto>();
try {
/*
calling Service, performing search using searchDto as a parameter, mapping result to resultViewDtos
*/
for(int i=0; i<resultViewDtos.size(); i++){
result.add(resultViewDtos.get(i).toResponseString()); //a new method
}
} catch(Exception e){
/* do something */
}
return result;
}
toResponseString() is a new method I have created in my resultViewDto that returns a string in which the attributes I need are separated by ":".
After filling the result and sending it back to ajax as a response, I then split the recieved response first on (',') to get the individual "rows" equivalent to a single resultViewDto, and then by (':') to get the values for each cell.
There might be a better way of solving it, but this woked like a charm.
I hope this will be usefull for someone else too.

Trying to get a JQuery Post to communicate with WCF, but the JSON data is not being accepted

I am using the following JQuery\JavaScript code to communicate with a WCF 4 REST service.
<script>
var serviceUrl = "http://services.xiine.com/Xiine/Live/AccountService/rest/json/Login";
var userInfo = {
"IsNotEncrypted":true,
"Password":null,
"UserName":null
};
var loginSuccess = function(data, textStatus, jqXHR){
console.log("yay");
};
var loginError = function(){
console.log("oh no");
};
$.post(serviceUrl , userInfo, loginSuccess);
$.post(serviceUrl , loginSuccess);
</script>
I am trying to establish why it is that the service will correctly return a false value when I do not pass the user data:
$.post(serviceUrl , loginSuccess);
As opposed to when I do pass user data, at which point it gives a POST 400 (Bad Request) error.
$.post(serviceUrl , userInfo, loginSuccess);
I am sure it has to do with how the JSON object, userInfo, is being built or interpreted, and I can post Fiddler 2 or WireShark dumps, if that will help. Just let me know...
I don't really have access to changing the WCF side of the service, so hopefully there is something I can do on my end to make this work.
Thanks!
Edit
I got a little more information... Apparently, the problem is that the server is responding with the following error:
The server encountered an error processing the request. The exception message is 'The incoming message >has an unexpected message format 'Raw'. The expected message formats for the operation are 'Xml', >'Json'. This can be because a WebContentTypeMapper has not been configured on the binding. See the >documentation of WebContentTypeMapper for more details.'. See server logs for more details. The >exception stack trace is:
at System.ServiceModel.Dispatcher.DemultiplexingDispatchMessageFormatter.DeserializeRequest(Message message, Object[] parameters) at System.ServiceModel.Dispatcher.UriTemplateDispatchFormatter.DeserializeRequest(Message message, Object[] parameters) at System.ServiceModel.Dispatcher.CompositeDispatchFormatter.DeserializeRequest(Message message, Object[] parameters) at System.ServiceModel.Dispatcher.DispatchOperationRuntime.DeserializeInputs(MessageRpc& rpc) at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc) at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)
So I am thinking I need to figure out how to get the object to go across the wire as a JSON object via a JQuery.post() method.
More information --- Again...
ok... There is no app.config or web.config, as such.
Here is what I can get as far as the contracts and code and what-not.
[ServiceContract]
public interface IAccount
{
[OperationContract]
bool Login(UserInformation user);
}
[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class AccountService : IAccount
{
public bool Login(UserInformation user)
{
//stuff...
}
}
[DataContract]
public class UserInformation
{
[DataMember(IsRequired = true)]
public string UserName;
[DataMember(IsRequired = true)]
public string Password;
[DataMember(IsRequired = true)]
public bool IsNotEncrypted;
}
public interface IUserInformation
{
UserInformation UserInformation { get; set; }
}
So, I found the answer to my question.
Someone attempted to point me in the right direction with a mention of the JSON.stringify() method, but it took me a little effort to get it implemented correctly.
In the end, I used WireShark to sniff out the http request, see what was actually being sent and received, and observe that not only did I need to stingify the data, but I also needed to specify the content type.
Here is the final code.
// This is the URL that is used for the service.
var serviceUrl = "http://services.xiine.com/Xiine/Live/AccountService/rest/json/Login";
// This is the JSON object passed to the service
var userInfo = {
"UserName": null,
"Password": null,
"IsNotEncrypted": true
};
// $.ajax is the longhand ajax call in JQuery
$.ajax({
type: "POST",
url: serviceUrl,
contentType: "application/json; charset=utf-8",
// Stringify the userInfo to send a string representation of the JSON Object
data: JSON.stringify(userInfo),
dataType: "json",
success: function(msg) {
console.log(msg);
}});
in the interface for your service, you need to have the OperationalContract attribute and in that attribute, you need to set the RequestFormat. Here is an example of what it might look like.
[OperationContract, WebInvoke(UriTemplate = "/runGenericMethodJSON", Method = "POST",
RequestFormat = WebMessageFormat.Json,
ResponseFormat = WebMessageFormat.Json,
BodyStyle = WebMessageBodyStyle.WrappedRequest)]

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