Merhaba Arkadaslar
Bu bolumde javax.ws.rs.WebApplicationException sinifini inceleyecegiz.

Error’lar , kullaniciya/client’a uygun Response mesajiyla donulebilir ya da bir exception olarak firlatilabilir (throw exception)

Eger Exception Mapper tanimlandiysa firlatilan exception’lar , runtime/calisma zamaninda JAX-RS tarafindan handle edilir.

Exception Mapper , exception’i HTTP response’a donusturebilir/convert.

Eger firlatilan exception mapper tarafindan handle edilmiyorsa bu durumda Container tarafindan handle edilir.

javax.ws.rs.WebApplicationException

JAX-RS , javax.ws.rs.WebApplicationException sinifini saglar.
WebApplicationException , uygulama kodu tarafindan firlatildiginda JAX-RS bu exception’i yakalar ve getResponse() metodunu cagirir.

Eger status code ya da Response objesi kullaniliyorsa bunlar yardimiyla HTP response olusturulur , eger yoksa status code varsayilan olarak 500 olacaktir. “Internal Server Error” , client’a donecektir.

JAX-RS also provides the javax.ws.rs.WebApplicationException. 
This can be thrown by application code and automatically 
processed by JAX-RS without having to write an explicit mapper.

javax.ws.rs.WebApplicationException

public class WebApplicationException extends RuntimeException {

	public WebApplicationException() {...}

	public WebApplicationException(Response response) {...}

	public WebApplicationException(int status) {...}

	public WebApplicationException(Response.Status status) {...}

	public WebApplicationException(Throwable cause) {...}

	public WebApplicationException(Throwable cause, Response response) {...}

	public WebApplicationException(Throwable cause, int status) {...}

	public WebApplicationException(Throwable cause, Response.Status status) {...}

	public Response getResponse() {...]
}

CustomerResource.java
Kodu inceleyelim…
Ilgili id degerinde Customer bulunmadiginda yeni bir WebApplicationException firlatiyoruz.
Response.Status.NOT_FOUND degerini arguman olarak veriyoruz.

Test amacli findCustomer metodu geriye null donmekte.
getCustomerName metodu da benzer sekilde WebApplicationException firlatiyor bura da Response.Status.NOT_IMPLEMENTED degerini veriyoruz.

package _19.exception.service;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Response;

import _19.exception.model.Customer;

@Path("/customer-exception")
public class CustomerResource {

	@GET
	@Path("/customer/{id}")
	public Customer getCustomer(@PathParam("id") int id) {

         	System.out.println("getCustomer is called....");
	
        	CustomerService service = new CustomerService();

		Customer customer = service.findCustomer(id);
		if (customer == null) {
			throw new WebApplicationException(Response.Status.NOT_FOUND);
		}
		return customer;
	}

	@GET
	@Path("/name/{id}")
	public String getCustomerName(@PathParam("id") int id) {
                System.out.println("getCustomerName is called...");
		throw new WebApplicationException(Response.Status.NOT_IMPLEMENTED);
	}
}

CustomerService.java

package _19.exception.service;

import _19.exception.model.Customer;

public class CustomerService {

	public Customer findCustomer(int id) {
		// simply return null
		return null;
	}

}

Ornegimizi test edelim ;

http://localhost:8080/injavawetrust.resteasy.tutorial/customer-exception/customer/1
http://localhost:8080/injavawetrust.jersey.tutorial/customer-exception/customer/1

RESTEasy icin ;

getCustomer is called....
.....
ERROR: RESTEASY002010: Failed to execute
javax.ws.rs.WebApplicationException: HTTP 404 Not Found
	at _19.exception.service.CustomerResource.getCustomer(CustomerResource.java:23)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
...

Jersey icin ;

Ornegimizi diger metot icin yapalim;

http://localhost:8080/injavawetrust.resteasy.tutorial/customer-exception/name/1
http://localhost:8080/injavawetrust.jersey.tutorial/customer-exception/name/1

RESTEasy icin ;

getCustomerName is called...
...
ERROR: RESTEASY002010: Failed to execute
javax.ws.rs.WebApplicationException: HTTP 501 Not Implemented
	at _19.exception.service.CustomerResource.getCustomerName(CustomerResource.java:33)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
....

Jersey icin ;

Github kaynak kodlar / source folder
injavawetrust.resteasy
injavawetrust.jersey

Yazimi burada sonlandiriyorum.
Herkese Bol Javali Gunler dilerim.
Be an oracle man , import java.*;
Levent Erguder
OCP, Java SE 6 Programmer
OCE, Java EE 6 Web Component Developer