I am trying to pass an argument to my #RESTController Spring Boot class.
In the #POSTMapping method I want to use a method of a self defined Java class for processing the received body and returning a response.
The Spring application is launched in Application.java. The Controller-Object seems to get created implicitly.
I already tried adding a constructor to my RESTController class. But I couldn't find a way to call that constructor with an argument.
// Application.java
public static void main (String[] args) {
SpringApplication.run(Application.class, args);
}
//ConnectorService.java
#RestController
public class ConnectorService {
private Solveable solver;
public ConnectorService() {}
public ConnectorService (Solveable solveable) {
this.solver = solveable;
}
#CrossOrigin(origins = "http://localhost:3000")
#PostMapping(path = "/maze")
public Solution Test(#RequestBody Test test) {
return solver.solve(test);
}
}
Even though i could define a second constructor, i didn't find any way to call it with my Object.
Use #RequestParam annotation to pass an argument
You can pass parameter with #RequestParam annotation like this:
#CrossOrigin(origins = "http://localhost:3000")
#PostMapping(path = "/maze")
public Solution Test(#RequestParam("paramName") String param, #RequestBody Test test) {
return solver.solve(test);
}
And you can put it with http request:
http://localhost:3000/maze?paramName=someValue
Assuming that you have POST request, there may be different ways to build this request, depending on the API testing tools you use.
#RestController follows the same rules for dependency injection as any other #Component in Spring framework.
If you have a single constructor, Spring will try to „inject” the parameters while instantiating the controller.
You need to register your dependency as a Spring bean.
It seems that you are new to Spring and you are starting with advanced topics like Spring Boot and rest controllers. Please find some time to read about the basics.
Yo can create a Bean configuration file to initialize your objects like:
#Configuration
#ComponentScan("com.xxx.xxx") // the base package you want to scan
public class Config {
#Bean
//where Solveable is a class and is annotated with an Spring's annotation
public Solveable solveable() {
return new Solveable();
}
}
And use the #Autowired annotation to inject the object in:
#Autowired
public ConnectorService (Solveable solveable) {
this.solver = solveable;
}
This last block will initialize or pass(what you want) the object to the ConnectorService class.
Related
I have two seperate projects, a projectApi (spring backend) and a projectUi (angular frontent).
I'm using maven-resource-plugin to combine them into one jar for production.
When I start the spring server, the connection between those two modules works fine.
Now I would like to customize the backend url path, so that a request like 'http://localhost:8088/login' looks like 'http://localhost:8088 /api/v1/login'.
I was able to do so, by adding the following entry to application.properties: spring.mvc.servlet-path=/api/v1 and modifying the base url, for calls from the ui to the api.
Since that change I'm getting a whitelabel error calling the ui (localhost:8088).
After some search, I tried to implement WebMvcConfigurer but it did not work for me. This is the reference stackoverflow link.
// Application.java
#SpringBootApplication
#EnableJpaRepositories
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
// UserRestService.java
#RestController
#RequestMapping("/user")
#Produces(MediaType.APPLICATION_JSON)
#Consumes(MediaType.APPLICATION_JSON)
public class UserRestService extends AbstractRestService {
...
#PostMapping("/login")
public String login(#RequestBody User user) throws CustomException {
return Response.ok(userService.loginUser(user, response));
}
}
// application.properties
server.port=8088
// without that entry the post request works fine -> localhost:8088/user/login
// adding that entry and trying to call: localhost:8088/api/v1/user/login i get whitelabel error
spring.mvc.servlet.path=/api/v1
Try to add "/api/v1/" to your controller otherwise all your controllers will be prefixed by that path and you will not be able to provide other versions withing the same application.
I would prefer to program to an interface. This helps in making better use of IOC. Add the URI prefix (/api/v1/) to the interface like below. It will append this prefix to all methods offered by the interface.
// Interface for UserRestService with URI prefix mentioned using Request mapping annotation
#RequestMapping(value = "/api/certs/", produces = { "application/json" },consumes = { "application/json" })
public interface IUserRestService {
String login(User user) throws CustomException;
}
//UserRestService Class
#RestController
#RequestMapping("/user", method = RequestMethod.POST)
public class UserRestService extends AbstractRestService implements IUserRestService{
...
#PostMapping("/login")
public String login(#RequestBody User user) throws CustomException {
return Response.ok(userService.loginUser(user, response));
}
}
I have a simple problem - SpringBootApplication doesn't see my controller - what's more weird - only one of three.
I have UserController, WalletController and DashboardController - this one is not visible for my application.
What I have already done is:
Every package with controller is under the main package, where my SpringBootApplication.class is,
I tried annotate main SpringBootApplication.class with #ComponentScan both with basePackages and basePackageClasses,
There is no other beans - which should be annotated #Component, I removed them and moved methods to my DashboardService.class
This is my controller, which is not visible:
DashboardController
And this is my package structure(seems to be right): Package Structure
Thank You for help!
EDIT:
It might be important, that I use the third-party api to get the data I need
In that methods I use url:
private String getNbpJson(String url) {
return new RestTemplate().getForObject(url, String.class);
}
private CurrentRateDTO getCurrentExchangeRate(String json) throws JsonProcessingException {
ObjectMapper mapper = new ObjectMapper();
JsonNode node = mapper.readTree(json);
String code = node.get("code").toString();
String date = node.get("rates").get(0).get("effectiveDate").toString();
double bid = node.get("rates").get(0).get("bid").asDouble();
double ask = node.get("rates").get(0).get("ask").asDouble();
return new CurrentRateDTO(code, date, bid, ask);
}
And then in ExchangeService this is my url
#Service
public class ExchangeRateService implements IExchangeRateService {
private static final Logger logger = LoggerFactory.getLogger(ExchangeRateService.class);
private String NBP_CURRENT_RATE_URL = "http://api.nbp.pl/api/exchangerates/rates/c/eur/2020-12-11/?format=json";
What's more... when I move methods from DashboardController to WalletController (which works)
Another thing that I have found out is that only methods, which make use of the third-party api don't work.
Basically, I retrieve data from the url above - I get the specific fields, create an objects with filled fields.
May it be a problem with retrieving data from the third-party and then implementing it in my app?
I have no more ideas for now...
Maybe your controller is registered but you type a slightly different url. Try this property logging.level.org.springframework.web.servlet.mvc.method.annotation: TRACE
and check on application startup if the controller is registered under some other url.
Try to add this to your controller
#RestController()
#RequestMapping("exchangerates")
Okay, I probably found out the problem... Before I have 3 controllers:
#RestController("/api")
public class UserController {}
#RestController("/wallets")
public class WalletController {}
#RestController("/exchangerates")
public class DashboardController {}
I changed the above to
#RestController("/api")
public class UserController {}
#RestController
public class WalletController {}
#RestController
public class DashboardController {}
So, basically I removed base ?endpoint? for each controller and now it works... It seems like basic endpoints in three RestControllers is too much and the third one is not available, but I don't know is it truth (I bet that it's not).
Why that happened then, can anybody explain that behaviour of controllers?
Thank You for explanantion.
I'm trying to achieve something like this:
#Controller
public SomeController {
#CustomConfig("var.a")
private String varA;
#CustomConfig("var.b")
private String varB;
#RequestMapping(value = "/", method = RequestMethod.GET)
public String get() {
return varA;
}
}
CustomConfig would be an #Interface class that accepts one value parameter. The reason why we are not using #Value is because this will not come from config file but from API (such as https://getconfig.com/get?key=var.a). So we are going to make HTTP request to inject it.
So far I've only manage to make something work if the varA and varB is inside get() method as parameter, by using below in a class that extends WebMvcConfigurerAdapter:
#Override
public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
CustomConfigResolver resolver = new CustomConfigResolver();
argumentResolvers.add(resolver);
}
And inside CustomComfigResolver.resolveArgument() we would do the HTTP query, but that's not really what we wanted, we need it to be injected as class variable.
Does anyone have experience in resolving it at class variable level?
Thank you
This could work if you use #Value instead of your own custom annotation. This uses the built in environment:
#Order(Ordered.HIGHEST_PRECEDENCE)
#Configuration
public class TcpIpPropertySourceConfig implements InitializingBean {
#Autowired
private ConfigurableEnvironment env;
#Autowired
private RestTemplate rest;
public void afterPropertiesSet() {
// Call your api using Resttemplate
RemoteProperties props = //Rest Call here;
// Add your source to the environment.
MutablePropertySources sources = env.getPropertySources();
sources.addFirst(new PropertiesPropertySource("customSourceName", props)
}
}
What you are trying to achieve is difficult when you start to consider "unhappy" scenarios. Server down / not reachable. You need to account for all of that in the method above.
I would highly recommend to instead use Spring Cloud Config. Great guide on that is here: https://www.baeldung.com/spring-cloud-configuration
This provides:
- Reloading of your #Value() properties, so no custom annotation needed.
- A more stable server and great Spring integration out of the box.
Best of all, it is easy to apply Retries and Backoffs if the configuration server goes down (see https://stackoverflow.com/a/44203216/2082699). This will make sure your app doesn't just crash when the server is not available.
I am not able to read a property from properties file through Spring Boot. I have a REST service which is working through the browser and Postman both and returning me a valid 200 response with data.
However, I am not able to read a property through this Spring Boot client using #Value annotation and getting following exception.
Exception:
helloWorldUrl = null
Exception in thread "main" java.lang.IllegalArgumentException: URI must not be null
at org.springframework.util.Assert.notNull(Assert.java:115)
at org.springframework.web.util.UriComponentsBuilder.fromUriString(UriComponentsBuilder.java:189)
at org.springframework.web.util.DefaultUriTemplateHandler.initUriComponentsBuilder(DefaultUriTemplateHandler.java:114)
at org.springframework.web.util.DefaultUriTemplateHandler.expandInternal(DefaultUriTemplateHandler.java:103)
at org.springframework.web.util.AbstractUriTemplateHandler.expand(AbstractUriTemplateHandler.java:106)
at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:612)
at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:287)
at com.example.HelloWorldClient.main(HelloWorldClient.java:19)
HelloWorldClient.java
public class HelloWorldClient {
#Value("${rest.uri}")
private static String helloWorldUrl;
public static void main(String[] args) {
System.out.println("helloWorldUrl = " + helloWorldUrl);
String message = new RestTemplate().getForObject(helloWorldUrl, String.class);
System.out.println("message = " + message);
}
}
application.properties
rest.uri=http://localhost:8080/hello
There are several problems in your code.
From the samples you posted, it seems that Spring is not even started. The main class should run the context in your main method.
#SpringBootApplication
public class HelloWorldApp {
public static void main(String[] args) {
SpringApplication.run(HelloWorldApp.class, args);
}
}
It isn't possible to inject a value into a static field. You should start with changing it into a regular class field.
The class must be managed by Spring container in order to make value injection available. If you use default component scan you can simply annotate the newly created client class with the #Component annotation.
#Component
public class HelloWorldClient {
// ...
}
If you don't want to annotate the class you can create a bean in one of your configuration classes or your main Spring Boot class.
#SpringBootApplication
public class HelloWorldApp {
// ...
#Bean
public HelloWorldClient helloWorldClient() {
return new HelloWorldClient();
}
}
However, if you are the owner of the class, the first option is preferable. No matter which way you choose, the goal is to make the Spring context aware of class existence so the injection process can happen.
I am writing spring controller, which injects a bean.
The bean is added in config(we use java config for everything):
#Bean
public NotificationService notificationService() {
return new NotificationService();
}
The service itself has few injected dependencies and few functions:
public class NotificationService {
#Inject
NotificationRepository notificationRepository;
#Inject
ProjectRepository projectRepository;
#Inject
ModelMapper modelMapper;
public NotificationDto create(NotificationDto notificationDto) {
//convert to domain object, save, return dto with updated ID
return notificationDto;
}
public void markAsRead(Long id, String recipientNip) {
//find notification, update status
}
}
Model mapper has almost no configuration, is only set to strict. Meanwhile repositoriers are interfaces extending JpaRepository with no custom functions. They are found by #EnableJpaRepositories.
Finally I have controller that tries to use the code above:
#RestController
#RequestMapping("/notifications")
public class NotificationController extends ExceptionHandlerController {
#Autowired
private NotificationService notificationService;
#PreAuthorize("isFullyAuthenticated() and hasRole('create_notification')")
#RequestMapping(method = RequestMethod.POST, consumes = MediaTypeExtension.APPLICATION_JSON_UTF8_VALUE)
public ResponseEntity<?> createNotification(#Valid #RequestBody(required = true) final NotificationDto notification) {
this.notificationService.create(notification);
final HttpHeaders headers = new HttpHeaders();
return new ResponseEntity<>(headers, HttpStatus.CREATED);
}
#PreAuthorize("isFullyAuthenticated() and hasRole('update_notification')")
#RequestMapping(value = "/{id}/read", method = RequestMethod.PUT)
private ResponseEntity<?> markNotificationAsRead(#PathVariable("id") Long id, #AuthenticatedContractor ContractorDto contractor) {
this.notificationService.markAsRead(id, contractor.getNip());
final HttpHeaders headers = new HttpHeaders();
return new ResponseEntity<>(headers, HttpStatus.OK);
}
}
All controllers are added trough #ComponentScan, based on their package.
As you can see both functions use notificationService. When I send POST for create on /notifications the notificationService is properly injected. In the same controller, when I do PUT request on /{id}/read, the notificationService is null.
I think it has something to do with spring putting things into its container, and for some reason not being able to do it for that one function. I have few more functions in the controller and in all of them notificationService is properly injected. I don't see any real difference between createNotification and markNotificationAsRead functions and I couldn't find anything even remotely related on google/stack. In all cases the service wouldn't inject at all because of configuration mistake.
Edit
I have tried changing things around in the function until it has started working. My final code looks like this:
#PreAuthorize("isFullyAuthenticated() and hasRole('update_notification')")
#RequestMapping(value = "{id}/read", method = RequestMethod.PUT)
public ResponseEntity<?> read(#PathVariable("id") Long id, #AuthenticatedContractor ContractorDto contractor) {
this.notificationService.markAsRead(id, contractor.getNip());
final HttpHeaders headers = new HttpHeaders();
return new ResponseEntity<>(headers, HttpStatus.OK);
}
and it works. Honestly I can't see any difference from my original code, and I have been staring at it for last hour or so. The imports are the same too.
I have also noticed(on unworking code) that while all functions from the controller on debug stack were marked as
NotificationController.functionName(arguments) line: x
The non working function was:
NotificationController$$EnhancerBySpringCGLIB$$64d88bfe(NotificationController).markNotificationAsRead(ContractorDto) line: 86
Why this single function was enhanced by spring CGLIB I have no idea. I have tried looking it up, but for now I came empty handed. Even though the code started to work I am leaving the question open in order to find the underlying cause.
Your method markNotificationAsRead is private and that probably causes the issue. I've just had same issue with final method - this message appeared in log:
2016-11-28 17:19:14.186 INFO 97079 --- [ main] o.s.aop.framework.CglibAopProxy : Unable to proxy method [public final java.util.Map com.package.controller.MyController.someMethod(javax.servlet.http.HttpServletResponse)] because it is final: All calls to this method via a proxy will NOT be routed to the target instance.
Looks like in one case we see a CGLib proxy, and in another - the actual class. Only one of those has all the fields injected, looks like the proxy has all fields nulls. But it doesn't matter - the point is your method should be public and not final in order to be proxied properly by #PreAuthorize methods.
I was also facing the same issue. It was all due to the private access modifier used and #PreAuthorize. Making the controller method private does not make an issue if you do not make it secure. But, to make secure, make it public.