Handling REST Exception - rest

Question

I'm using a REST service with CXF that does a GET request with an int parameter.
#Path("parkingservice")
public interface ParkingService {
/**
* #param id
* #return
*/
#GET
#Path("/parkings/{id}/parkingState")
#Produces(MediaType.APPLICATION_JSON)
ParkingState getStatus(#PathParam("id") int id);
}
I call my service this way :
http://domain.com:8087/services/rest/parkingservice/parkings/2805/parkingState
When I put a number, it works, but when I put a String, I have this exception :
WARNING: javax.ws.rs.NotFoundException: java.lang.NumberFormatException: For input string: "dd"
at org.apache.cxf.jaxrs.utils.InjectionUtils.handleParameter(InjectionUtils.java:322)
at org.apache.cxf.jaxrs.utils.InjectionUtils.createParameterObject(InjectionUtils.java:845)
at org.apache.cxf.jaxrs.utils.JAXRSUtils.readFromUriParam(JAXRSUtils.java:1041)
at org.apache.cxf.jaxrs.utils.JAXRSUtils.createHttpParameterValue(JAXRSUtils.java:733)
at org.apache.cxf.jaxrs.utils.JAXRSUtils.processParameter(JAXRSUtils.java:708)
at org.apache.cxf.jaxrs.utils.JAXRSUtils.processParameters(JAXRSUtils.java:655)
at org.apache.cxf.jaxrs.interceptor.JAXRSInInterceptor.processRequest(JAXRSInInterceptor.java:238)
at org.apache.cxf.jaxrs.interceptor.JAXRSInInterceptor.handleMessage(JAXRSInInterceptor.java:99)
at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:271)
at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:239)
at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:223)
at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:203)
at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:137)
at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:158)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:243)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doGet(AbstractHTTPServlet.java:168)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:219)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.NumberFormatException: For input string: "dd"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:48)
at java.lang.Integer.parseInt(Integer.java:449)
at java.lang.Integer.valueOf(Integer.java:554)
at org.apache.cxf.common.util.PrimitiveUtils.read(PrimitiveUtils.java:60)
at org.apache.cxf.jaxrs.utils.InjectionUtils.handleParameter(InjectionUtils.java:310)
... 34 more
I'd like to avoid having this exception no matter what type I give..or to find a way to handle this exception with a message like "please provide a good Id"
Thanks a lot

Answer 1

Add an exception mapper to your rest layer. Code goes something like this :
package com.cxf.util;
import javax.ws.rs.core.Response;
import javax.ws.rs.ext.ExceptionMapper;
public class CustomExceptionMapper implements
ExceptionMapper<NotFoundException> {
public CustomExceptionMapper () {
}
#Override
public Response toResponse(NotFoundException arg0) {
//your logic and return accordingly
return Response.serverError().build();
}
}
And you if you are using Spring to maintain your service beans and cxf configuration then add this mapper as a bean under jaxrs:providers tag, where jaxrs is this : xmlns:jaxrs="http://cxf.apache.org/jaxrs"
Whenever your application will throw notfoundexception it will go in this class.
Second option is that you can take this parameter as String then parse it in your try catch block. On NumberformatException return 400 status code. Since you have a custom POJO as return, you can take a object of HttpServletResponse from org.apache.cxf.jaxrs.ext.MessageContext and set status in it. Below is a dummy code:
public class RestServiceImpl implements RestService{
#Context
MessageContext context;
public CustomPojo getData(String id){
HttpServletResponse httpResponse = context.getHttpServletResponse();
try{
}catch(NumberFormatException e){
httpResponse.setStatusCode(400);
}
}
}

Answer 2

Use the below signature for getStatus method, this would work both ways.
ParkingState getStatus(#PathParam("id") String id);

Answer 3

Your getStatus(#PathParam("id") int id); takes integer as an argument and you are trying to pass String instead of int, that's why it's throwing an exception of NumberFormatException.
You have to handle it,or make a Check is the incoming value is int if not then so a message "please provide a valid input".