I am having a question that how can I send JSON Object from Springs MVC so that I can convert it into a JavaScript Object on my HTML Page.
In a traditional way I do it: Below is a snippet from Java Servlet which sets a request attribute and forward it to the JSP Page.
JSONObject jsonObj = new JSONObject();
jsonObj.put("name","test");
jsonObj.put("age",24);
request.setAttribute("jsonObj",jsonObj);
request.getRequestDispatcher("test.jsp").forward(request,response);
In JSP I retrieve as :
<script type="text/javascript">
var jsonObj =<%=request.getAttribute("jsonObj"); %>;
alert("name = "+jsonObj.name+" ; age = "+jsonObj.age); // This will output name and age from the JSON Object
</script>
So what I need to ask how can I do the same in Springs MVC. How can I send the JSONObject from Dispatcher Servlet, and convert it to JS object in my JSP page ?
An easy way to do this using the ObjectMapper. It will create an JSON String from your Object. And that you can send to your view/jsp.
I put an small example of a controller I do this (just snipped).
#Controller
public class UsersSettingsController {
#Autowired
UserSettingsDefaultService userSettingsService;
#RequestMapping(value="/userSettings/dynamic/userSettings", method=RequestMethod.GET)
public ModelAndView get() throws Exception {
ModelAndView mav = new ModelAndView();
ObjectMapper mapper = new ObjectMapper();
User user = (User)SecurityContextHolder.getContext().getAuthentication().getPrincipal();
UserSettings userSet = userSettingsService.getUserSettingsByUser(user);
mav.addObject("userSettingsJSON", mapper.writeValueAsString(userSet));
mav.setViewName("userSettings/dynamic/filter");
return mav;
}
}
Or course can you create your JSON Object in your Contoller step by step like you did in your example. Then you don't need the Mapper, just sending the String to your View.
In the JSP you load the json String like this into a JS var:
var jsonString = '${userSettingsJSON}';
To get elements from JSON String or parse, see: http://www.json.org/js.html.
I'm an KnockOut Framework Fan would do it with it.
I think you should use ajax(for example jquery),the following is spring mvc
#RequestMapping(value = "/admin/new/list", method = RequestMethod.GET)
#ResponseBody
public List<News> list()
{
return newsDao.findAll();
}
and in the jsp page,you may use ajax util (for example jquery)
$.ajax({
type: "GET",
url: '<c:url value="/admin/new/list"/>',
cache:false,
dataType :'json',
success: function(data){
alert(data);
}
});
the data is json object
I don't know whether the above is what you need
A much easier way to do this is to include the Jackson dependencies in maven and use #ResponseBody to return a JSON representation of the object, without having to manually write the manipulation.
Have a look at the example below, you shouldn't have to write any tranlation to JSON code.
http://www.mkyong.com/spring-mvc/spring-3-mvc-and-json-example/
As per your requirement, I suggest you to use AJAX call with JSON as data type.
For example :
$.ajax({
url: "getFormatIdDescMap?compId="+compId,
global: false,
type: "POST",
dataType:"json",
contanttype:'text/json',
async:false,
error:function(){
alert("Error during retrieving the foramt ID List");
},
success: function(data){
//REMOVE ALL THE OLD VALUES OF FORMAT DROP DOWN
removeDropDownVals('formatList');
var optn;
for(var index=0;index<data.formatKeys.length;index++){
optn = document.createElement("option");
document.getElementById("formatList").options.add(optn);
optn.text =data.formatDescs[index];
optn.value=data.formatKeys[index];
}
}
});
});
In the code above, I am preparing a new list of Formats based on company ID. You can iterate over the response.
It will give response text as per your requirements. But here note that .. if you are getting json Array in the response, it will contain that data in square bracket like..[1,2,3] and If you are getting response in JSON Object then it will be displayed in curly braces like {"data",[1,2,3]}.
Related
I have a simple JSP file with some radios, one text input and one button.
In the button onClick I am doing an Ajax request to a Spring controller as you can see bellow:
function callFiltrarViaAJAX() {
var filtro = $("#filtro").val();
var optFiltro = $('input[name=optFiltro]:checked').val();
$.ajax({
type : "GET",
url : "filtrar",
//dataType : "json",
data : {
filtro : filtro,
optFiltro : optFiltro
},
success: function(data) {
console.log("SUCCESS: ", data);
},
error: function(e) {
console.log("ERROR: ", e);
},
done: function(e) {
console.log("DONE");
}
});
}
In the Spring controller I am receiving this request with success with the following code:
#Controller
public class FiltroController {
#RequestMapping(value = "/filtrar", method = RequestMethod.GET)
public #ResponseBody String filtrarVacina(FiltroTO filtro, HttpServletResponse response, ModelAndView model) {
VacinaTO v = new VacinaTO();
v.setId(new Long(10));
v.setLote("Lote 1");
v.setNome("BCG");
model.addObject("vacina", v);
response.setStatus(200);
return "TEST OK";
}
}
As you can see in the code above, I'm adding a POJO object in the ModelAndView that I'am trying to use in the JSP to show the return of the Ajax request in a table.
My Ajax request returns with success too but the problem is that even returning with success I can't use the POJO object, when I try to access the object by expression language I got nothing.
I've been searching about this situation and I found a lot of contents but none of the solutions that I've found works for me, but I found an interesting answer:
JSP inside ListItems onclick
So, is it means that I can't get a new parameter in the same JSP file with a Ajax request ? If yes, would be a JSON file the better way to get the return from the Spring controller ?
You can't access the model because you're returning an arbitrary string from controller instead of the view in which you want to access model.
If you're trying to access vacine from some.jsp, then you should return some from the controller method.
Of course, what I said is valid if you have proper ViewResolver configuration.
I am using spring mvc. I need to pass a json object from my jsp page to controller.
My ajax code:
function createJSON() {
jsonObj = [];
item = {};
$(".values").each(function() {
var code = $(this).attr('id');
item[code] = $('#' + code).val();
});
var content=JSON.stringify(item)
$.ajax({
type: 'POST',
contentType : 'application/json; charset=utf-8',
url: "/pms/season/submit",
data: content,
dataType: "json",
success : function(data) {
alert(response);
},
error : function(e) {
alert('Error: ' + e);
}
});
}
My controller code:
#RequestMapping(value = "/submit", method = RequestMethod.POST)
public void saveNewUsers( #RequestParam ("json") String json) {
System.out.println( "json ::::"+json );
}
But it's not working.
#RequestParam("json") means that you are intending to include a request parameter called json in the URI, i.e. /submit?json=...
I think you intend to get the request body, i.e. #RequestBody.
I would then suggest that, unless you really need the raw JSON string, you would have the #RequestBody translated to a Java object for you:
public void saveNewUsers(#RequestBody MyDto myDto) {
...
}
where MyDto would have getters/setters and fields matching the JSON class.
You can over omit the #RequestBody annotation if you annotate the controller with #RestController, instead of #Controller.
If you definitely want the raw JSON string, then take a look at this previous question: Return literal JSON strings in spring mvc #ResponseBody
In servlet I got something like:
Map<String, String> myFruits = giveMeSomeFruits();
request.serAttribute("myFruits", myFruits);
And in .js I got:
<label ng-repeat='(key, value) in myFruits'>
<input type='checkbox' value='{{value}}' ng-click='eat(value)'/> {{key}}
</lable>
Now I need to pass the map myFruits from servlet to angularJs, is there any clean way to do that?
This might work.
1.Yes have an ajax call to the servlet from angular.
2.Convert the map
to Json in Java using JSONObject and send the response from
servlet as JSON.
return new JSONObject(myFruits);
$.ajax(
url : url, // Controller URL
success: function(resultJSON){
//Assign resultJSON to myFruits variable
$scope.myFruits = resultJSON;
}});
In your controller, define a function called getMap maybe. Make a call to the servlet using your url for the same, using Method 'GET'.
$scope.getMap = function () {
$http({method: 'GET', url: 'your url'}).
success(function (data, status, headers, config) {
console.log(data);
$scope.myFruits = {data: data};
}).
error(function (data, status, headers, config) {
console.log("error");
});
};
Now you have to override the doGet() function in your servlet, which retrieves this map for you through a query to your database.
Convert the map to Json using
response = gsonHelper.toJson(yourMap);
Send this json as response back to your controller and assign it to a variable defined in scope, say fruits.
Now you can use fruits in your markup to iterate through the map.
I am trying to POST to a Spring MVC controller method via ajax. Using Chrome's developer tools, I can tell that the values from the form are being sent, but in the method, the form values are null.
Here is the jquery call:
var form = $('#renegotiationForm').serialize();
$.ajax({
method:'POST',
url:'/renegotiate/wizard/startRenegotiation',
data:{'renegotiationForm': form},
success: function(data) { this.transitionTo(data); }
});
Here is the Spring MVC method (meant to return only a single string):
#RequestMapping(value="wizard/startRenegotiation", method = RequestMethod.POST)
public #ResponseBody String processStart(#ModelAttribute("renegotiationForm") RenegotiationForm form, BindingResult bindingResult) {
log.debug("Entered showStart(), method=POST");
RenegotiationType type = RenegotiationType.valueOf(form.getRenoType().trim().toUpperCase());
RenegotiationActivity activity = RenegotiationActivity.valueOf(form.getRenoActivity().trim().toUpperCase());
String result = "";
if (type == RenegotiationType.TYPE1 && activity == RenegotiationActivity.ACTIVITY1) {
result = "deleteType1";
}
return result;
}
The values are bound using the Spring Form taglib, and I have confirmed that the path attributes of the form tags match the fields of the RenegotiationForm.
I think it's because you are trying to send an "string" from ajax and you want to get and Object (RenegotiationForm), try to change it to String and Format in Server-side. I recommend you to add the type you are sending from client-side, too.
#RequestMapping(value = "wizard/startRenegotiation", method = RequestMethod.POST, produces="application/json")
Found the answer. Further on in my code, I had a function like this:
var ajaxcall = function() { $.ajax({
// ajax settings
});
}
Unfortunately, setting it up this way doesn't make it work as a jquery deferred, and specifically I couldn't use the .then() function to process of ajax requests.
Thanks for the help.
I'm trying to make a simple AJAX call in my Spring MVC project but am running into trouble. I am making my AJAX request by sending an String type argument and I'm wanting to get an ArrayList type back. I've read many tutorials at this point and can't figure out what's wrong with my AJAX/Controller configuration. I am using the ResponseBody annotation when trying to return my needed result back to the view. In this controller I am not returning an updated ModeAndView object, but this shouldn't matter since the page does not need to be refreshed because I'm using AJAX. Below is my AJAX call and controller code. I would really appreciate it if someone could give me a hint on what I'm doing wrong here.
function getdays() {
var monthSelected = $("#monthselect option:selected").text();
alert(monthSelected);
$.ajax({
url : '${pageContext.request.contextPath}/ajaxdays',
data: monthSelected,
success : function(data)
{
$('#daySelect').html(data);
alert(data);
}
});
}
Here is my controller class:
#Controller
#SessionAttributes
public class WorkstationController
{
#RequestMapping(value = "/ajaxdays", method = RequestMethod.GET)
public #ResponseBody
ArrayList<String> getTime(HttpServletRequest request)
{
ArrayList<String> retList = new ArrayList<>();
retList = this.getList();
return retList;
}
}
you have following errors
wrong url
change url : 'ajaxdays.html'to ${pageContext.request.contextPath}/ajaxdays
no parameter passed
you are not passing any data to server side so there is no need to write data: monthSelected
URL mentioned in ajax call should be the context path followed by the controller mapping. And '.html' should not be specified.
url: ${pageContext.request.contextPath}/ajaxdays