Need some help in the following case:
I have set an application as Liferay portlet and i am using JSF/Primefaces for builing my views. For data modelling i am using Hibernate.
In a certain view i load a so called "image annotator" which is using Javascript tools for gathering user input (annotation on an image canvas). This information i would like to be able to save in a file/database and then re-use when the user edits again a specific image.
Here is my view:
<h:head>
<script src="#{facesContext.externalContext.requestContextPath}/js/OpenLayers.js" />
<script src="#{facesContext.externalContext.requestContextPath}/js/image-viewer.js" />
<script src="#{facesContext.externalContext.requestContextPath}/js/xml2js/xml2json.js" />
<script src="#{facesContext.externalContext.requestContextPath}/js/xml2js/xml2json.min.js" />
...
</head>
...
<p:fieldset legend="Viewer">
<p:outputPanel layout="block" styleClass="imageEditorImagePanel" />
</p:fieldset>
....
So the image and the relevant jscript tools (OpenLayers) are loaded in imageEditorPanel placeholder.
The javascript code (image-viewer.js) gathers user input in a json (GEOJson) object, and this object i would like to pass to a back bean controller when Save button (jscript) is selected:
...
//define save button
var save = new OpenLayers.Control.Button({
title: 'Save', text: 'Save',
trigger: function(){
var GEOJSON_PARSER = new OpenLayers.Format.GeoJSON();
var vectorLayerAsJson = GEOJSON_PARSER.write(vlayer.features);
...
So i want to pass 'vectorLayerAsJson' object to a java controller (backbean) ...
I am trying to implement an ajax call like:
jQuery.ajax({
type: 'POST',
url: 'imageannotations',
contentType: 'application/json',
data: vectorLayerAsJson,
success : function(data) { alert("success")}
});
can anybody help on how am i going to make this ajax request as also how am i going to implement my controller class?
You can initiate a call to a java managed bean via Javascript using primefaces p:remoteCommand. Answers how to send the String as an argument can be found here.
In the managed bean/java controller, just have a String variable with getter/setter and an action method to start the unserialization (following is untested code):
#ManagedBean(name="testBean")
public class Test {
public String actionOnString() {
String value = FacesContext.getCurrentInstance()
.getExternalContext().getRequestParameterMap().get("param");
// do your unserialize and actions here
return "";
}
}
Within JSF have something like
<p:remoteCommand name="sendJSONToServer" action="#{testBean.actionOnString}" />
and as javascript on the desired position
sendJSONToServer({param: vectorLayerAsJson});
should do the job.
Direct ajax-push is also possible via PrimePush, using the athmosphere framework. Possibly, that might be overkill for what you try to achieve.
Update 1
Of course, when you get a JSON-Object serialized (so to say "n String format), you have to JSONize it in Javascript - this answer "How to parse JSON in JavaScript" might help you further regarding that.
Hope it helps...
Related
I'm trying to use ajax with thymeleaf. I designed a simple html page with two input field. I would like to use addEventHandler for the value of first input text, then I want to send it to controller and make calculation, after that I need to write it in same html form in the second field which returns from controller.
For example:
first input text value -> controller (make calculation) -> (write value) in second input text.
My html page is
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<link rel='stylesheet prefetch' href='http://maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css'>
<link rel="stylesheet" href="css/style.css">
</head>
<body>
<input type="text" name="Thing" value=""/>
<script th:inline="javascript">
window.onload = function () {
/* event listener */
document.getElementsByName("Thing")[0].addEventListener('change', doThing);
/* function */
function doThing() {
var url = '#{/testurl}';
$("#fill").load(url);
alert('Horray! Someone wrote "' + this.value + '"!');
}
}
</script>
<!-- Results block -->
<div id="fill">
<p th:text="${responseMsg}"/></div>
</div>
</body>
</html>
My controller
#RequestMapping(value = "/testurl", method = RequestMethod.GET)
public String test(Model model) {
model.addAttribute("responseMsg","calcualted value")
return "test";
}
However I cannot call controller from ajax. Could you help me?
There are a few issues with your code. First of all, it looks like you're using the same template for both the initial loading of the application, and returning the calculated result.
You should split these two into different calls if you're using AJAX, since one of the goals of AJAX is that you don't need to reload an entire page for one change.
If you need to return a simple value, you should use a separate request method like this:
#GetMapping("/calculation")
#ResponseBody
public int multiply(#RequestParam int input) {
return input * 2; // The calculation
}
What's important to notice here is that I'm using #ResponseBody and that I'm sending the input to this method as a #RequestParam.
Since you will be returning the calculated value directly, you don't need the Model, nor the responseMsg. So you can remove that from your original request mapping.
You can also remove it from your <div id="fill">, since the goal of your code is to use AJAX to fill this element and not to use Thymeleaf. So you can just have an empty element:
<div id="fill">
</div>
Now, there are also a few issues with your Thymeleaf page. As far as I know, '#{/testurl}' is not the valid syntax for providing URLs. The proper syntax would be to use square brackets:
var url = [[#{/calculation}]];
You also have to make sure you change the url to point to the new request mapping. Additionally, this doesn't look as beautiful since it isn't valid JavaScript, the alternative way to write this is:
var url = /*[[ #{/calculation} ]]*/ null;
Now, your script has also a few issues. Since you're using $().load() you must make sure that you have jQuery loaded somewhere (this looks like jQuery syntax so I'm assuming you want to use jQuery).
You also have to send your input parameter somehow. To do that, you can use the event object that will be passed to the doThing() function, for example:
function doThing(evt) {
var url = [[#{/calculation}]];
$("#fill").load(url + '?input=' + evt.target.value);
alert('Horray! Someone wrote "' + this.value + '"!');
}
As you can see, I'm also adding the ?input=, which will allow you to send the passed value to the AJAX call.
Finally, using $().load() isn't the best way to work with AJAX calls unless you try to load partial HTML templates asynchronously. If you just want to load a value, you could use the following code in stead:
$.get({
url: /*[[ #{/calculation} ]]*/ null,
data: { input: evt.target.value }
}).then(function(result) {
$('#fill').text(result);
});
Be aware that $.get() can be cached by browsers (the same applies to $().load() though). So if the same input parameter can lead to different results, you want to use different HTTP methods (POST for example).
I have an ajax call to a jsp page with certain data.
$.ajax({
type: "POST",
url: "jsp/order.jsp",
data: {
"dishId" : id,
"dishPrice" : price,
"dishName" : name
},
success: function(msg) {
alert(msg);
}
});
I want to read the data in the order.jsp using jstl. However I am not able to do that using the following statements.
<c:out value='${dishName}' />
<c:out value='${dishId}' />
I know it can be done using scriptlets but wanted to do it using jstl.
All HTTP request parameters are in EL available via implicit ${param} mapping.
So, this should do:
<c:out value="${param.dishName}" />
<c:out value="${param.dishId}" />
See also:
Java EE 5 tutorial - Expression Language - Implicit Objects
Unrelated to the concrete problem, do note that there's quite a difference between "JSTL" and "EL". Those <c:xxx> things are JSTL tags. Those ${...} things is EL. You can also use EL standalone:
${param.dishName}
${param.dishId}
However, that opens a potential XSS attack hole, hence the need for <c:out> to escape it.
And, you'd better use a servlet instead of a JSP to deal with HTTP requests. See also How to use Servlets and Ajax?.
In my project i am using springMVC+Hibernet .When EndUser click his/her profile Link i want to show his/her Information .For that i am using ajax in spring MVC .Now my controller return data in the form JSON object but i don't know How to update the object in my view Page.In That Object i have more than 25 fields any one help me how to update JSON object data to my jsp lables(FirstName,LastName.....)
MY code like this
$.ajax({
type: "GET",
url: "AjaxActionController?",
dataType: "json",
success: function(data){
alert(data);
var firstName = data.getFristName();
}
}
NOW i want to Update this data into my view layer
One "simple" way to do it is to set an id on the html element you want the data in and use jQuery to set it. This will get less and less "simple" as your application grows.
html:
<div id="firstName"/>
javascript:
success:function(data){
var firstName = data.getFirstName();
$('#firstName').text(firstName);
}
If you want something more manageable for a large app, the concept is called "data binding". Try a javascript databinding framework, such as Knockout, Ember/Backbone, Angular, Epoxy/Backbone. jQuery can do it too, with some work.
I am learning ASP.NET MVC. I have to submit a to controller side after validation in client-side(in jquery). How this can be done? Should i use <form action="#" method="post"> instead of <form action="Controller/Method" method="post"> and add an event handler in click event of submit button of , to send via ajax etc? What should i do? pls help
You are on the right track, and what you suggested will work.
A better method would be to leave the original action intact, providing backwards compatibility to older browsers. You would then create the event handler as normal, and include code to prevent the default submit behavior, and use ajax instead.
$('#submitbutton').live('click', function(e){ e.preventDefault(); });
The easiest way to do this is to use the jQuery forms plugin.
This is my go-to plugin for this type of thing. Basically it will take your existing form, action url etc and convert the submission to an ajax call automatically. From the website:
The jQuery Form Plugin allows you to easily and unobtrusively upgrade
HTML forms to use AJAX. The main methods, ajaxForm and ajaxSubmit,
gather information from the form element to determine how to manage
the submit process. Both of these methods support numerous options
which allows you to have full control over how the data is submitted.
It is extremely useful for sites hosted in low cost web hosting
providers with limited features and functionality. Submitting a form
with AJAX doesn't get any easier than this!
It will also degrade gracefully if, for some reason, javascript is disabled. Take a look at the website, there are a bunch of clear examples and demos.
This is how I do:
In jQuery:
$('document').ready(function() {
$('input[name=submit]').click(function(e) {
url = 'the link';
var dataToBeSent = $("form#myForm").serialize();
$.ajax({
url : url,
data : dataToBeSent,
success : function(response) {
alert('Success');
},
error : function(request, textStatus, errorThrown) {
alert('Something bad happened');
}
});
e.preventDefault();
});
In the other page I get the variables and process them. My form is
<form name = "myForm" method = "post">//AJAX does the calling part so action is not needed.
<input type = "text" name = "fname"/>
<input type= "submit" name = "submit"/>
<FORM>
In the action page have something like this
name = Request.QueryString("fname")
UPDATE: As one of your comment in David's post, you are not sure how to send values of the form. Try the below function you will get a clear idea how this code works. serialize() method does the trick.
$('input[name=submit]').click(function(e){
var dataToBeSent = $("form#myForm").serialize();
alert(dataToBeSent);
e.preventDefault();
})
I'm trying to access another service's API, using my model's fields as the keywords in the API request. The URL would be like like so:
http://api.example.com/json/?first_name=FNAME&last_name=LNAME&key={key}
Here's my code from views.py:
class ExamplePersonView(ListView):
context_object_name = "example_person"
template_name = "templates/example_person.html"
def get_queryset(self):
lname = get_object_or_404(ExamplePeople, lname__iexact=self.args[0])
return ExamplePeople.objects.filter(lname=lname)
From what I understand, I'll need to use AJAX to communicate between my page template and my views.py to send the request and then present the information on the page.
I've found several Django apps that make it easy to turn your models into a public API, but none that help you access API's from another service. Does anyone know of an app like that?
If not, does anyone have a good understanding of using AJAX with Django to make the request and present it in the template?
There's several ways to communicate with a "foreign" API. There's no necessity for ajax. Ajax is just for making background calls in a template, triggering whatever event you have in mind.
But let's say you want to communicate with the facebook GraphAPI to retrieve a profile
http://graph.facebook.com/bill.clinton
The standard result is serialized as JSON, which implements easily into AJAX or any JavaScript library, hence the name JavaScript Object Notation.
So an example with AJAX might be:
function callFacebook() {
$.ajax({
type: "GET",
data: ({}),
dataType: 'json',
url: "http://graph.facebook.com/bill.clinton",
success: function(data){
alert("Hi I am former "+data.name);
}
});
}
callFacebook();
Include this in your javascript file or within your template between script tags and you should get a nice alert message:
Hi I am former President Bill Clinton
Now you could turn this alert into something more meaningful, and put it within a h1 tag (not sure why this is meaningful)
$("body").html("<h1>"+data.name+"</h1>");
But sometimes you would want to retrieve data and do something with it server side in your application.
So create a django urlpattern and view, e.g.:
from urllib2 import urlopen
from django.http import HttpResponse
from django.utils import simplejson
def call_bill(request):
url = "http://graph.facebook.com/bill.clinton"
json = urlopen(url).read()
# do whatever you want
return HttpResponse(simplejson.dumps(json), mimetype="application/json")
# add this to your url patterns
url("^call_bill_clinton/$", call_bill)
Now visit your url
As a logic result, it's also perfectly possible to trigger async events by some user action. Eg the URL parameter in the previously mentioned ajax example, could also be a django url like "/call_bill_clinton/".
<!-- add a button to call the function -->
<button onclick="callFacebook();">Call Bill</button>
function callFacebook() {
$.ajax({
type: "GET",
data: ({}),
dataType: 'json',
url: "/call_bill_clinton/",
success: function(data){
alert("Hi I am former "+data.name+" and I came from Django");
}
});
)
// remove the auto call
Furthermore ajax calls let you do the same trickery as http requests, you can use a variety of request methods combined with cool javascript events, like a beforeSend event
beforeSend: function() {
$('#loading').show();
},
Where the #loading could be something like:
<div id="loading" style="display:none;">
<img src="{% static "images/loading.gif" %}" />
</div>