I am trying to retrieve some JSON data in my javascript by making a call to the controller. The controller returns a MappingJacksonJsonView ModelandView, but the .getJSON is always reporting a 404 at .../handhygiene.json.
Is there a problem with the way I am returning the ModelandView from the controller?
Controller
#RequestMapping(value = "/{room}/handhygiene.json", method = RequestMethod.GET)
public ModelAndView getHandHygienePageAsync(
#PathVariable(value = "room") String roomCode) {
ModelAndView mav = new ModelAndView(new MappingJacksonJsonView());
mav.getModelMap().addAttribute(blahblahblah); //adds some attributes
...
return mav;
}
Javascript
var currentURL = window.location;
$.getJSON(currentURL + ".json",
function(data) {
... //does stuff with data
}
If you're trying to get only an JSON object from Ajax request, you need to add #ResponseBody to your method, and make you result object as return from your method.
The #ResponseBody tells to Spring that he need to serialize your object to return to the client as content-type. By default, Spring uses JSON Serialization. ModelAndView will try to return an .JSP page. Maybe you don't have this jsp page on your resources so, the server return 404 error.
I Think this code should work for you:
#RequestMapping(value = "/{room}/handhygiene.json", method = RequestMethod.GET)
public #ResponseBody Room getHandHygienePageAsync(#PathVariable(value = "room") String roomCode) {
Room room = myService.findRoomByRoomCode(roomCode);
return room;
}
I'm assuming you're using the Room as your result object, but it may be another object or ArrayList, for example.
You cant take a look here for Spring example, and here for example and configuration.
Related
I have a controller method as this:
#PostMapping("/view/{location}")
public ModelAndView view(#PathVariable("location") String location) {
ModelAndView modelAndView = new ModelAndView();
return modelAndView;
}
This method is capable of receiving requests like
"/view/a" or "/view/b" such that pathVariable location becomes a or b.
But I want this same method to receive all the requests having /view in their beginning, such that the pathVariable "location" holds the rest of the data.
for example
for a request as /view/a/b/c, the pathVariable location will become a/b/c.
like a file system hierarchy.
Please let me know if such a thing is possible in Spring MVC, and I am very new at this.
Check out this article
The idea is to map all the paths which start with /view to a single controller method by adding **, but you'll have to use HttpServletRequest instead of #PathVariable.
So, in your case, it'll be something like this:
#PostMapping("/view/**")
public ModelAndView view(HttpServletRequest request) {
String pathVariable = extractId(request);
ModelAndView modelAndView = new ModelAndView();
return modelAndView;
}
private String extractId(HttpServletRequest request) {
String path = (String) request.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
String bestMatchPattern = (String) request.getAttribute(HandlerMapping.BEST_MATCHING_PATTERN_ATTRIBUTE);
return new AntPathMatcher().extractPathWithinPattern(bestMatchPattern, path);
}
Also, check out this question
You could go by the approach shared earlier,
#GetMapping(value = "blog/**")
public Blog show(HttpServletRequest request){
String id = (String)
request.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
System.out.println(id);
int blogId = Integer.parseInt(id);
return blogMockedData.getBlogById(blogId);
}
Second way is to use RequestParam instead of Path variable.
you will call the api using :
http://localhost:8080/blog?input=nabcd/2/nr/dje/jfir/dye
controller will look like :
#GetMapping(value = "blog")
public Blog show(#RequestParam("input") String input){
If you are certain about the number of slash in your input, you could go with any approach mentioned here help
I'm new to mvc spring and I have some code from the internet like the following:
#RequestMapping(value = "/newContact", method = RequestMethod.GET)
public ModelAndView newContact(ModelAndView model) {
Contact newContact = new Contact();
model.addObject("contact", newContact);
model.setViewName("ContactForm");
return model;
}
#RequestMapping(value = "/saveContact", method = RequestMethod.POST)
public ModelAndView saveContact(#ModelAttribute Contact contact) {
contactDAO.saveOrUpdate(contact);
return new ModelAndView("redirect:/");
}
#RequestMapping(value = "/deleteContact", method = RequestMethod.GET)
public ModelAndView deleteContact(HttpServletRequest request) {
int contactId = Integer.parseInt(request.getParameter("id"));
contactDAO.delete(contactId);
return new ModelAndView("redirect:/");
}
My question is,
what is the purpose of using and using in any case with # ModelAttribute, ModelAndView mode and HttpServletRequest request?
Thanks you.
Please check https://stackoverflow.com/a/33422321/3530898. I my opinion ModelAttribute is used usually with form transport objects (i.e. bean classes whose fields contain the form data), ModelAndView is used when you want to set view name and model object in a single method of a controller. Both ModelAndView and Model uses HttpServletRequest internally, Spring has added wrapper classes over HttpServletRequest to make development easier for developer. But sometime you need HttpServletRequest class for instance, when you want to capture a query parameter in an Ajax call etc
I'm trying to teach myself Spring by creating a very simple web application. I have a class to create "Note" objects:
#Controller
#RequestMapping(value = "/notes")
public class NoteRestController {
#Autowired
private MappingJackson2JsonView jsonView;
[...]
#ResponseStatus(HttpStatus.CREATED)
#RequestMapping(method = RequestMethod.POST, consumes = {
MediaType.APPLICATION_JSON_VALUE,
MediaType.APPLICATION_FORM_URLENCODED_VALUE })
public ModelAndView create(final Model model,
#Valid #ModelAttribute final Note note, final BindingResult result) {
ModelAndView mav;
// how can I test the request source?
if (<requesting from HTML FORM>) {
// return jsonView
mav = new ModelAndView(jsonView);
} else {
// return JSP view
mav = new ModelAndView("note", "model", model);
}
model.addAttribute("note", note);
if (result.hasErrors()) {
model.addAttribute("errors", result.getAllErrors());
// on error, redirect back to note page with form
// return new ModelAndView("note/note", "model", model);
return mav;
}
note.setId(daoService.createNote(note));
return mav;
}
}
I would like to be able to use a single method (like the above) to handle requests from both an AJAX post AND a HTML form post. If triggered by AJAX I would like to return JSON (with validation errors if present), and if it is triggered by a HTML form, I would like to return to the JSP using the form taglib
<%# taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
and show validation errors next to input fields using e.g.
<form:errors path="title" cssClass="errorMessage"></form:errors>
Is this possible, or should I be creating two controllers; one for the REST/JSON, and one for HTML/form? Maybe there is something I can pass into the method that can be interrogated to determibne the request source, but I can't see it right now.
What would be the "best practice" in this case?
EDIT 1:
Trying answer from #ring-bearer first as it allows for the same URL pattern, but having issues.
Using methods:
// used to handle JSON/XML
#RequestMapping(method = RequestMethod.POST, produces = {
MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE })
public #ResponseBody Note create(
#Valid #ModelAttribute final Note note, final BindingResult result) {
[...]
}
// used to handle form view
#RequestMapping(method = RequestMethod.POST)
public ModelAndView createForView(final Model model,
#Valid #ModelAttribute final Note note, final BindingResult result) {
[...]
}
Interestingly, the HTML form submission, still gets handled by create() and not createForView(). After looking at the form submission request headers, I see that this Accept header:
text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
By adding produces = "text/html" to #RequestMapping on createForView(), all 3 scenarios work (form, AJAX/JSON, AJAX/XML).
Is this normal, or am I still missing something?
This can be achieved using "content negotiation". Spring MVC needs to be enabled for content negotiation using a "contentNegotiationManager" definition. It can be set up using Java or XML configuration. The configuration will centrally manage media type mappings(json, xml etc). Once that is set up, a controller class can be built to cater to both JSON and View(HTML). Below is a generic example(uncompiled), it should be easy to refactor your class to similar structure to avoid violation of DRY.
#Controller
class ReportController{
//1- Method for JSON/marshalling types(XML)
#RequestMapping(value="/report", produces={"application/xml", "application/json"})
#ResponseStatus(HttpStatus.OK)
public #ResponseBody List<ReportPara> generateReport(Principal principal) {
return reportService.generateReport(principal);
}
//2- For View technologies ( Eg:JSP HTML)
#RequestMapping("/report")
public String generateReportForView(Model model, Principal principal) {
model.addAttribute( generateReport(principal) );
// Return the view to use for rendering the response
return ¨reports/main¨;
}
}
Which of the two #RequestMapping methods will execute? It is determined by content negotiation definition. Eg: URLs such as report.xml or report.json map to the first method, any other URLs ending in report.anything map to the second.
The following will be easier to maintain:
#Controller
class NoteController {
#Autowired NoteService service;
#RequestMapping(method = RequestMethod.POST, value = "/note")
public ModelAndView createFromForm(#ModelAttribute #Valid Note note, BindingResult result) {
return new ModelAndView("note", create(note));
}
#RequestMapping(method = RequestMethod.POST, value = "/api/note")
#ResponseBody
public Note createFromApi(#RequestBody Note note) {
return create(note);
}
private Note create(Note note) {
return service.create(note);
}
}
In order to access the redirect attributes in the redirected method, we utilize the model's map, like this :
#Controller
#RequestMapping("/foo")
public class FooController {
#RequestMapping(value = "/bar", method = RequestMethod.GET)
public ModelAndView handleGet(Model map) {
String some = (String) map.asMap().get("some");
}
#RequestMapping(value = "/bar", method = RequestMethod.POST)
public ModelAndView handlePost(RedirectAttributes redirectAttrs) {
redirectAttrs.addFlashAttributes("some", "thing");
return new ModelAndView().setViewName("redirect:/foo/bar");
}
}
But, why can't we access them in this way :
#RequestMapping(value = "/bar", method = RequestMethod.GET)
public ModelAndView handleGet(RedirectAttributes redAttr) {
String some = redAttr.getFlashAttributes().get("some");
}
If the only purpose of adding flashAttributes is that they become available to the model in the redirected method, what's the purpose of getFlashAttributes() ?
RedirectAttributes are for setting flash attributes before redirection. They are merged into model after the redirection so there is no reason to access them again via RedirectAttributes again as you have suggested.
Being able to work with the attributes just like with a map might be useful. You can check what have you set (containsKey, isEmpty, ...). However the use of the wildcard generic parameter Map<String, ?> getFlashAttributes() prevents writing into map and it is strange why they have used it instead of a plain Object parameter.
I have a problem here and I need your help.
Im trying to retrieve an integer value from the controller to the jsp.
In my jsp I have an ajax call:
$("#hdnCustomerSize").load(contextPath+"/customer/size", function() {
// some codes
});
In my controller:
#RequestMapping(method = RequestMethod.GET, value="/size")
public void getCustomerSize(Model model) {
model.addAttribute("customerSize", customerService.getCustomers().size());
}
My problem is Im getting an exception:
javax.servlet.ServletException: Could not resolve view with name 'customer/size' in servlet with name 'tombuyandsell'.
I know Im getting this exception because I intentionally did not map this in views.properties. The reason is I only want to get the integer value size and not a whole jsp page. Please help.
Use the #ResponseBody annotation and return the int as a String. #ResponseBody will cause the return type to be written to the response HTTP body.
#RequestMapping(method = RequestMethod.GET, value="/size")
#ResponseBody
public String getGroupChatSize(Model model) {
return Integer.toString(customerService.getCustomers().size());
}
Documentation
Try with #ResponseBody:
#ResponseBody
#RequestMapping(method = RequestMethod.GET, value="/size")
public int getGroupChatSize() {
return customerService.getCustomers().size();
}