For below URL's I receive a 404 error, this is fine since the URL's do not exist. Is it possible to create these servlets while the server is running before the error page is returned ?
http://127.0.0.1:8888/test1
http://127.0.0.1:8888/test1/test2
I'm thinking perhaps to create a generic controller that intercepts all urls if the current servlet does not exist, then create it ?
Assuming that by Spring you mean Spring MVC, you could do something like this:
#Controller
public class YourController {
#RequestMapping("/mappingA")
public void methodA() {
// (...)
}
#RequestMapping("/mappingB")
public void methodB() {
// (...)
}
// Catches all non-matched requests.
#RequestMapping("/*")
public void fake404(HttpServletRequest request) {
var uri = request.getRequestURI();
// (...)
}
}
Related
I am working with spring boot with a h2 database. I would like to return a 201 message when the register is inserted succesfully and a 400 when is duplicated. I am using ResponseEntity to achieve this, fot example , the next is my create method from the Service:
#Override
public ResponseEntity<Object> createEvent(EventDTO eventDTO) {
if (eventRepository.findOne(eventDTO.getId()) != null) {
//THis is a test, I am looking for the correct message
return new ResponseEntity(HttpStatus.IM_USED);
}
Actor actor = actorService.createActor(eventDTO.getActor());
Repo repo = repoService.createRepo(eventDTO.getRepo());
Event event = new Event(eventDTO.getId(), eventDTO.getType(), actor, repo, createdAt(eventDTO));
eventRepository.save(event);
return new ResponseEntity(HttpStatus.CREATED);
}
This is my controller:
#PostMapping(value = "/events")
public ResponseEntity addEvent(#RequestBody EventDTO body) {
return eventService.createEvent(body);
}
But I'm not getting any message in the browser, I am doing different tests with postman and when I consult for all the events, the result is correct, but each time that I make a post I dont get any message in the browser, I am not pretty sure what is the cause of this issue. Any ideas?
The ideal way to send Response to the client is to create DTO/DAO with ResponseEntity in Controller
Controller.java
#PostMapping("/test")
public ResponseEntity<Object> testApi(#RequestBody User user)
{
System.out.println("User: "+user.toString());
return assetService.testApi(user);
}
Service.java
public ResponseEntity testApi(User user) {
if(user.getId()==1)
return new ResponseEntity("Created",HttpStatus.CREATED);
else
return new ResponseEntity("Used",HttpStatus.IM_USED);
// for BAD_REQUEST(400) return new ResponseEntity("Bad Request",HttpStatus.BAD_REQUEST);
}
Tested using Postman
Status 201 Created
Status 226 IM Used
Okay, I really don't feel good that service sending the ResponseEntity but not Controller.You could use #ResponseStatus and ExceptionHandler classes for these cases, like below.
Create a class in exception package
GlobalExceptionHandler.java
#ControllerAdvice
public class GlobalExceptionHandler {
#ResponseStatus(HttpStatus.BAD_REQUEST)
#ExceptionHandler(DataIntegrityViolationException.class) // NOTE : You could create a custom exception class to handle duplications
public void handleConflict() {
}
}
Controller.java
#PostMapping(value = "/events")
#ResponseStatus(HttpStatus.CREATED) // You don't have to return any object this will take care of the status
public void addEvent(#RequestBody EventDTO body) {
eventService.createEvent(body);
}
Now changing the service would look like,
Service.java
#Override
public void createEvent(EventDTO eventDTO) { // No need to return
if (eventRepository.findOne(eventDTO.getId()) != null) {
throw new DataIntegrityViolationException("Already exists"); // you have to throw the same exception which you have marked in Handler class
}
Actor actor = actorService.createActor(eventDTO.getActor());
Repo repo = repoService.createRepo(eventDTO.getRepo());
Event event = new Event(eventDTO.getId(), eventDTO.getType(), actor, repo, createdAt(eventDTO));
eventRepository.save(event);
}
Need some small help about Spring Feign client. So here is the situation,
I have 2 Spring boot services. Let’s say Service A and Service B. I have configured my Service A with Feign client through which I call the Service B method.
So here is the code for my Service A,
My FeignCleint config interface,
#FeignClient(name = "FeignClient", url = "http://localhost:8081/ServiceB/hello")
public interface FeignApi {
#RequestMapping(method = RequestMethod.GET)
ResponseEntity<?> hello();
}
And my rest controller that uses above feign config to call the Service B method,
#RestController
public class ApiController {
#Autowired
private FeignApi feignApi;
#RequestMapping(value = "/callServiceB")
public ResponseEntity<?> companyInfo() {
ResponseEntity<?> response = new ResponseEntity("OK Response", HttpStatus.OK);
try {
response = feignApi.hello();
// Code for some other things related to application.
return response;
} catch (Exception ex) {
System.out.println("Service A Exception block reached.");
return new ResponseEntity(ex.getMessage(), HttpStatus.BAD_REQUEST);
}
}
}
below is my controller for Service B,
#RestController
public class MyController {
#GetMapping("/hello")
public String hello() throws Exception {
if (true) {
throw new Exception("Service B Exception...");
}
return "Hello World";
}
}
And my Controller advice to handle the exception that I am manually throwing,
#ControllerAdvice
public class MyControllerAdvice {
#ExceptionHandler
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
public ResponseEntity<?> handleException(Exception exception, Model model) {
return new ResponseEntity<>("Caused due to : " + exception.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
}
}
Now my flow is like below,
As you can see, I am calling service B from service A using feign client. My service B is throwing an exception manually which I am catching using the controller advice and sending the exception details as an ResponseEntity back to the calling service A. So that Service A can process the details and move forward based on that.
The problem is when I hit the call from Service A using
http://localhost:8080/feign/callServiceB
The service B fails as expected. Now what I expect is that the Service A should receive the response back in form of the ResponseEntity. But what really happens is that the flow enters the exception block instead of staying in the try block. I can see this line printed,
"Service A Exception block reached."
This is what I don't understand. If I have managed the service B exception using controller advice and sent back the response to service A in form of ResponseEntity, then how come the flow of service A enters catch block. I expect it to stay in try block only as I want to process further based on the data.
Any idea, how can I get around this thing? Or is this how it will behave even when I am using controller advice to manage exceptions? What should be the expected behavior in this case?
Please advice.
By default Feign throws FeignException for any error situation.
Make use of fallback mechanism to handle failures.
#FeignClient(name = "FeignClient", url = "http://localhost:8081/ServiceB/hello", fallback= FeignApiFallback.class)
public interface FeignApi {
#RequestMapping(method = RequestMethod.GET)
ResponseEntity<?> hello();
}
#Component
class FeignApiFallback implements FeignApi {
#Override
public ResponseEntity<?> hello() {
//do more logic here
return ResponseEntity.ok().build();
}
}
make sure you add below property to wrap methods in hystrix commands in recent releases
feign.hystrix.enabled=true
Any status other than 200, feign client will consider it as an exception and you are setting HttpStatus.INTERNAL_SERVER_ERROR in your controller advice.
You can use custom ErrorDecoder
refer https://github.com/OpenFeign/feign/wiki/Custom-error-handling
I have created a springboot application that contains some Rest API endpoints in .../api/myEndpoints... and thymeleaf templates for some UI forms the user can interact with.
Since I added an errorController:
#Controller
#RequestMapping("/error")
public class ErrorController {
#RequestMapping(method = RequestMethod.GET)
public String index(Model model) {
return "error";
}
}
whenever an exception is being thrown in my RestControllers, I receive an empty white website containing the word "error". This maybe makes sense for the web frontend, but not for my api. For the API I want spring to output the standard JSON result e.g.:
{
"timestamp": 1473148776095,
"status": 400,
"error": "Bad request",
"exception": "java.lang.IllegalArgumentException",
"message": "A required parameter is missing (IllegalArgumentException)",
"path": "/api/greet"
}
When I remove the index method from the ErrorController, then I always receive the JSON output.
My question is: Is it somehow possible to exclude the automatic redirection to /error for all api urls (../api/*) only?
Thanks a lot.
There may be a better solution out there, until then... here's how you can achieve what you asked:
(1) Disable ErrorMvcAutoConfiguration
Add this to your application.properties:
spring.autoconfigure.exclude: org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration
(2) Define two ControllerAdvices
Since we disabled ErrorMvcAutoConfiguration, we need to catch the exception ourself. Create one advice to catch error for a specific package, and another advice to catch all other. They each redirect to a different url.
//Catch exception for API.
#ControllerAdvice(basePackageClasses = YourApiController.class)
#Order(Ordered.HIGHEST_PRECEDENCE)
public static class ErrorApiAdvice {
#ExceptionHandler(Throwable.class)
public String catchApiExceptions(Throwable e) {
return "/error/api";
}
}
//Catch all other exceptions
#ControllerAdvice
#Order(Ordered.LOWEST_PRECEDENCE)
public static class ErrorAdvice {
#ExceptionHandler(Throwable.class)
public String catchOtherExceptions() {
return "/error";
}
}
(3) create a controller to handle the error page
This is where you can have different logic in your error handling:
#RestController
public class MyErrorController {
#RequestMapping("/error/api")
public String name(Throwable e) {
return "api error";
}
#RequestMapping("/error")
public String error() {
return "error";
}
}
With Spring-Boot 1.4.x you can also implement ErrorViewResolver (see this doc):
#Component
public class MyErrorViewResolver implements ErrorViewResolver {
#Override
public ModelAndView resolveErrorView(HttpServletRequest request,
HttpStatus status, Map<String, Object> model) {
if("/one".equals(model.get("path"))){
return new ModelAndView("/errorpage/api");
}else{
return new ModelAndView("/errorpage");
}
}
}
I'm trying to setup a simple Liferay + Maven portlet that can utilize REST services to fetch data from an external database. I believe I'm most of the way there but I'm stuck on the #RequestMapping within a Liferay portlet. I have a #Controller setup that runs fine on the View phase of the portlet
#Controller
#RequestMapping(value = "VIEW")
public class RiskController {
#ActionMapping
public void handleActionRequest(ActionRequest request, ActionResponse response)throws Exception {
return;
}
#RenderMapping
public ModelAndView handleRenderRequest(RenderRequest request, RenderResponse response, ModelMap model) {
model.addAttribute("helloWord", "123");
return new ModelAndView("index", model);
}
}
Now I'd like to write some service classes and fetch my data, but I'm not sure how to set this up as far as the Paths/URLs are concerned from a Liferay perspective (i.e., localhost:8080/myPortlet/myAjaxCall). I want to do something basic like return an Object via JSON like so
#RequestMapping(value = "/getMyData/123", method = RequestMethod.GET)
public #ResponseBody Data getData(#RequestParam long gcfId) {
Data data = dataRepo.getMyData(123);
return data;
}
Can anyone help get me in the right direction? Can provide more code if needed
I am setting up a simple RESTful controller for a Todo resource with an XML representation. It all works great - until I try to redirect. For example, when I POST a new Todo and attempt to redirect to its new URL (for example /todos/5, I get the following error:
Error 500 Unable to locate object to be marshalled in model: {}
I do know the POST worked because I can manually go to the new URL (/todos/5) and see the newly created resource. Its only when trying to redirect that I get the failure. I know in my example I could just return the newly created Todo object, but I have other cases where a redirect makes sense. The error looks like a marshaling problem, but like I said, it only rears itself when I add redirects to my RESTful methods, and does not occur if manually hitting the URL I am redirecting to.
A snippet of the code:
#Controller
#RequestMapping("/todos")
public class TodoController {
#RequestMapping(value="/{id}", method=GET)
public Todo getTodo(#PathVariable long id) {
return todoRepository.findById(id);
}
#RequestMapping(method=POST)
public String newTodo(#RequestBody Todo todo) {
todoRepository.save(todo); // generates and sets the ID on the todo object
return "redirect:/todos/" + todo.getId();
}
... more methods ...
public void setTodoRepository(TodoRepository todoRepository) {
this.todoRepository = todoRepository;
}
private TodoRepository todoRepository;
}
Can you spot what I am missing? I am suspecting it may have something to do with returning a redirect string - perhaps instead of it triggering a redirect it is actually being passed to the XML marshaling view used by my view resolver (not shown - but typical of all the online examples), and JAXB (the configured OXM tool) doesn't know what to do with it. Just a guess...
Thanks in advance.
This happend because redirect: prefix is handled by InternalResourceViewResolver (actually, by UrlBasedViewResolver). So, if you don't have InternalResourceViewResolver or your request doesn't get into it during view resolution process, redirect is not handled.
To solve it, you can either return a RedirectView from your controller method, or add a custom view resolver for handling redirects:
public class RedirectViewResolver implements ViewResolver, Ordered {
private int order = Integer.MIN_VALUE;
public View resolveViewName(String viewName, Locale arg1) throws Exception {
if (viewName.startsWith(UrlBasedViewResolver.REDIRECT_URL_PREFIX)) {
String redirectUrl = viewName.substring(UrlBasedViewResolver.REDIRECT_URL_PREFIX.length());
return new RedirectView(redirectUrl, true);
}
return null;
}
public int getOrder() {
return order;
}
public void setOrder(int order) {
this.order = order;
}
}