PageNotFound - Request method 'GET' not supported - java

I am getting this error while calling an API from postman, after I hosted my spring app in VM. Locally it works. But Get methods in my VMs are working.
[http-nio-8081-exec-4] PageNotFound - Request method 'GET' not supported
My controller method looks like this:
#RestController
#RequestMapping("/orders/")
public class OrdersController {}
#PostMapping(value = "create", produces = "text/plain")
private String createOrder(#RequestBody POCreationRequest request) throws ParseException {
The API request running forever and dont get any response. I found the exception in my log. Any idea on this issue?

You created two urls there:
url/orders/ -> accepts get/post/etc... (though its not implemented)
url/orders/create -> accepts post

#RestController
#RequestMapping("/orders")
public class OrdersController {
#PostMapping(value = "create", produces = "text/plain")
private String createOrder(#RequestBody POCreationRequest request) throws ParseException {
System.out.println(request)}
}
You can try the above code.

You are trying to make a GET request on an only POST endpoint, thus then not loading the page. Your endpoint should be of type GET. You can also have the same endpoint for GET and POST requests as follows:
#RestController
#RequestMapping("/orders/")
public class OrdersController {}
#PostMapping(value = "create", produces = "text/plain")
private String createOrder(#RequestBody POCreationRequest request) throws ParseException {
//Parse post requests
}
#GetMapping(value= "create")
private String servePage() {
return create; //create is the name of the html view.
}
Now when going to localhost:8080/orders/create it should serve the view.
You can also make the GET mapping return a JSON object by:
#GetMapping(value= "create")
private String serveJSON() {
return "{\"hello\": \"world\"}"; //The string is treated as JSON and not as a view.
}

Related

Why RequestMappings with the same URL but producing different MediaTypes works?

I want to understand why Spring application is starting if I have same 2 requestMapping URL,params(no params) and produces type(JSON).By default the methods is producing JSON(I tested XML and others and I get 500 error, I don't have dependencies).I want to know if it is a Intellij or Spring problem,or is it normal to start and to get overriden second Get becouse if I put produces = MediaType.APPLICATION_JSON_VALUE on the second too,I get error.Here is the example that work:
#GetMapping(produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<List<ExampleDTO>> getMethodd1() {
return ResponseEntity.ok(ExampleStore.available);
}
#GetMapping()
public ResponseEntity<List<ExampleDTO>> getMethodd2() {
return ResponseEntity.ok(ExampleStore.available);
}
And this example doesn't start anymore:
#GetMapping(produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<List<ExampleDTO>> getMethodd1() {
return ResponseEntity.ok(ExampleStore.available);
}
#GetMapping(produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<List<ExampleDTO>> getMethodd2() {
return ResponseEntity.ok(ExampleStore.available);
}
PS:I know a request should be different by params or url.
I think it is quite obvious if you think it a little further. See these three controller methods with the same url:
#GetMapping(path = "/sameurl")
public String text() throws JsonProcessingException {
return "some data\n";
}
#GetMapping(path = "/sameurl", produces = MediaType.APPLICATION_XML_VALUE)
public String xml() throws JsonProcessingException {
return "<data>some data</data>\n";
}
#GetMapping(path = "/sameurl", produces = MediaType.APPLICATION_JSON_VALUE)
public String json() throws JsonProcessingException {
return "{\"data\": \"some data\"}\n";
}
As you saw already in your question that what distinguishes them is what each method produces.
The method that is actually invoked is selected by what client accepts which gives you the flexiblity to choose at the controller level how to process the request without checking accept types yourself.
With above API urls and corresponding calls the results:
curl -H "Accept:application/someformat" localhost:8080/sameurl
some data
curl -H "Accept:application/json" localhost:8080/sameurl
{"data": "some data"}
curl -H "Accept:application/xml" localhost:8080/sameurl
<data>some data</data>
What then is an actual duplicate is a request mapping having the same URL and same type to produce. There is no distinguishing attribute anymore and Spring can not tell which method to use.

What is the difference between #RequestMapping and #PostMapping

in the below example, I am trying to undersatnd the difference between #RequestMapping and #PostMapping.
For #RequestMapping:
when i do the POST request:
http://localhost:8085/call1/initparam1?val=1111 via postman, it executes correctly.
but when its is proceeded by by GET request
http://localhost:8085/call1/getparam1
i do not get 1111 as a result.
For #PostMapping, when i do the POST request:
http://localhost:8085/call1/initparam2/1999 via postman, it executes correctly.
but when its is proceeded by by GET request
http://localhost:8085/call1/getparam1
i do not get 1999 as a result.
please explain to me what is the difference between using both annotations, as i spent time googling and researching but i could not figure out why the first example is not working.
Controller1
#Controller
#ResponseBody
#RequestMapping("/call1")
public class Call1 {
public String str = "inti";
#RequestMapping(value = "/initparam1", method = RequestMethod.POST)
public void initparam1(#RequestParam(value = "val") String val) {
this.str = val;
}
#PostMapping(value = "/initparam2/{val}")
public void initparam2(#PathVariable String val) {
this.str = val;
}
#RequestMapping("/getparam1")
#ResponseBody
public String getParam1() {
return this.str;
}
}
From the #PostMapping docs :
Specifically, #PostMapping is a composed annotation that acts as a shortcut for #RequestMapping(method = RequestMethod.POST).
So it is only convenience annotation that is more "verbose" and indicates that method annotated with it is used for handling POST HTTP requests.
I have just checked your controller methods with 2.1.4 spring boot version and your scenarios work as expected so there has to be something wrong in your configuration or the way you are sending requests.

How to implement "load balancer" using spring boot?

Depends on request body content I need to redirect http requests to URL_1 or URL_2.
I started controller implementation:
#RestController
public class RouteController {
#Autowired
private RestTemplate restTemplate;
#RequestMapping(value = "/**")
public HttpServletResponse route(HttpServletRequest request) {
String body = IOUtils.toString(request.getReader());
if(isFirstServer(body)) {
//send request to URL_1 and get response
} else {
//send request to URL_2 and get response
}
}
}
Request might be GET or POST ot PUT or PATCH etc.
Could you help me to write that code?
I've asked a somehow similar question a while ago. Plea see Server side redirect for REST call for more context.
The best way (to my current understanding) you could achieve this is by manually invoking the desired endpoints from your initial endpoint.
#RestController
public class RouteController {
#Value("${firstUrl}")
private String firstUrl;
#Value("${secondUrl}")
private String secondUrl;
#Autowired
private RestTemplate restTemplate;
#RequestMapping(value = "/**")
public void route(HttpServletRequest request) {
String body = IOUtils.toString(request.getReader());
if(isFirstServer(body)) {
restTemplate.exchange(firstUrl,
getHttpMethod(request),
getHttpEntity(request),
getResponseClass(request),
getParams(params));
} else {
restTemplate.exchange(secondUrl,
getHttpMethod(request),
getHttpEntity(request),
getResponseClass(request),
getParams(params))
}
}
}
Example implementation for getHttpMethod:
public HttpMethod getHttpMethod(HttpServletRequest request) {
return HttpMethod.valueOf(request.getMethod());
}
Similar implementations for getHttpEntity, getResponseClass and getParams. They are used for converting the data from the HttpServletRequest request to the types required by the exchange method.
There seem to be a lot of better ways of doing this for a Spring MVC app, but I guess that it does not apply to your context.
Another way you could achieve this would be defining your own REST client and adding the routing logic there.

Spring boot rest controller not converting request body to custom object

I have spring boot application which used spring rest controller .
This is the controller , below is the response an getting. Am using postman tool for sending request to this controller. And am sending content type as application/json
#RequestMapping(value = "/test", method = RequestMethod.POST)
public String test(#RequestBody WebApp webapp, #RequestBody String propertyFiles, #RequestBody String) {
System.out.println("webapp :"+webapp);
System.out.println("propertyFiles :"+propertyFiles);
System.out.println("propertyText :"+propertyText);
return "ok good";
}
2018-03-21 12:18:47.732  WARN 8520 --- [nio-8099-exec-3] .w.s.m.s.DefaultHandlerExceptionResolver : Resolved exception caused by Handler execution: org.springframework.http.converter.HttpMessageNotReadableException: I/O error while reading input message; nested exception is java.io.IOException: Stream closed
This is my postman request
{
"webapp":{"webappName":"cavion17","path":"ud1","isQA":true},
"propertyFiles":"vchannel",
"propertytText":"demo property"}
I tried by removing the RequestBody annotation, then able to hit the service , but param objects are received as null.
So please suggest how to retrieve objects in the restcontroller?
You cannot use multiple #RequestBody annotations in Spring. You need to wrap all these in an object.
Some like this
// some imports here
public class IncomingRequestBody {
private Webapp webapp;
private String propertryFiles;
private String propertyText;
// add getters and setters here
}
And in your controller
#RequestMapping(value = "/test", method = RequestMethod.POST)
public String test(#RequestBody IncomingRequestBody requestBody) {
System.out.println(requestBody.getPropertyFiles());
// other statement
return "ok good";
}
Read more here
Passing multiple variables in #RequestBody to a Spring MVC controller using Ajax
Based on the sample postman payload you gave, you will need:
public class MyObject {
private MyWebapp webapp;
private String propertyFiles;
private String propertytText;
// your getters /setters here as needed
}
and
public class MyWebapp {
private String webappName;
private String path;
private boolean isQA;
// getters setters here
}
Then on your controller change it to:
#RequestMapping(value = "/test", method = RequestMethod.POST)
public String test(#RequestBody MyObject payload) {
// then access the fields from the payload like
payload.getPropertyFiles();
return "ok good";
}

Transferring an object via REST

I've been trying to send an object from one application to another using rest.
Sender:
#Controller
public class Sender {
#RequestMapping(value = "/comMessageApp-api/getMessages")
public String restGetMessages() {
String url = "http://localhost:8079/comMessageApp-api/responseMessages";
HttpEntity<Dto2> entity = new HttpEntity<>(new Dto2());
ResponseEntity<Dto2> response = restTemplate.exchange(url, HttpMethod.POST, entity, Dto2.class);
}
}
Receiver:
#RestController
public class Receiver {
#RequestMapping(value = "/comMessageApp-api/responseMessages")
public void restResponseMessages(HttpEntity<Dto2> request) {
System.out.println(request.getBody());
}
}
DTO:
public class Dto2 {
private String string = "Test string";
public Dto2() {
}
public String getString() {
return string;
}
public void setString(String string) {
this.string = string;
}
}
Jackson is used serialization/deserialization.
Any ideas, why request.getBody() printed in the Receiver is null???
I tried to send the object inside HttpEntity and inside RequestEntity. No success in both cases. On the receiving side I always get null.
Your sender (client) side is very close but your server side doesn't return a value so change the type to Void:
ResponseEntity<Void> response = restOps.exchange(url, HttpMethod.POST, entity, Void.class);
Your receiver (server) side is not quite set up correctly either, you need to set the HTTP method to [edited] POST. You'll also need to tell Spring to map the body of the request (your rest payload) onto the parameter;
#RequestMapping(value = "/comMessageApp-api/responseMessages", method=RequestMethod.POST)
public void recieveDto (#RequestBody final Dto dto) {
System.out.println(dto.toString());
}
[EDIT] Brainfart, the http method should be set to POST on receive annotation.
[Further suggestion]
403 errors may be due to Spring Security, if you have it switched on (check your POM if you're not sure) try this;
#Configuration
#EnableWebSecurity
public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
#Override
protected void configure(HttpSecurity http) throws Exception {
http
.csrf()
.disable()
.authorizeRequests().
antMatchers("/**").permitAll();
}
}
You'll want to be tightening up security once you know it works.
try to use #RequestMapping(method = RequestMethod.POST, produces = "application/json", consumes = "application/json")

Categories