RequestMethod.GET Method Not Working with HttpEntity Argument

[rence1005]

I'm developing a RESTful web service with the Spring 3 MVC approach. I have the following method defined in my controller:

@RequestMapping(method=RequestMapping.GET,
value="/getXXXXYYYY/person/{identifier}")
public ResponseEntity<CustomReturnClass> getXXXXYYYY(
@PathVariable String identifier,
HttpEntity<CustomPersonClass> customPersonClass)
{
System.out.println("Inside of getXXXXYYYY method");
...
}

I wrote the following client code to call / test the above method:

ResponseEntity<CustomReturnClass> response = null;
CustomPersonClass customPersonClass = new CustomPersonClass();
customerPersonClass.setAttribute1("stringValue");
HttpEntity<CustomPersonClass> requestEntity =
new HttpEntity<CustomPersonClass>(customPersonClass);
String identifier = "identifierString";

response = restTemplate.exchange(
BASE_URL+"/getXXXXYYYY/person/{identifier}",
HttpMethod.GET,
requestEntity,
CustomReturnClass.class,
identifier);

However when I run this client code I get the following error on the server side:

ERROR [[Catalina].[localhost].[/webAppName].[webAppName]] Servlet.service() for servlet webAppName threw Exception
java.lang.NullPointerException
at com.sun.xml.bind.v2.runtime.unmarshaller.Unmarshal lingContext.getLocation(UnmarshallingContext.java: 560)
at com.sun.xml.bind.v2.runtime.Coordinator.propagateE vent(Coordinator.java:153)
at com.sun.xml.bind.v2.runtime.Coordinator.fatalError (Coordinator.java:147)
...

If I change the controller method signature to look like this:

@RequestMapping(method=RequestMapping.POST,
value="/getXXXXYYYY/person/{identifier}")
public ResponseEntity<CustomReturnClass> getXXXXYYYY(
@PathVariable String identifier,
HttpEntity<CustomPersonClass> customPersonClass)
{
System.out.println("Inside of getXXXXYYYY method");
...
}

and the client to call the method like this:

ResponseEntity<CustomReturnClass> response = null;
CustomPersonClass customPersonClass = new CustomPersonClass();
customerPersonClass.setAttribute1("stringValue");
HttpEntity<CustomPersonClass> requestEntity =
new HttpEntity<CustomPersonClass>(customPersonClass);
String identifier = "identifierString";

response = restTemplate.exchange(
BASE_URL+"/getXXXXYYYY/person/{identifier}",
HttpMethod.POST,
requestEntity,
CustomReturnClass.class,
identifier);

I get the "Inside of getXXXXYYYY method" printed out to the server the controller is deployed to. It also works if I change the controller method signature / caller to use a PUT.

Is the HttpEntity argument not supported for GET? I have seen the following example from the spring documentation (http://static.springsource.org/sprin.../remoting.html), in section 19.9.1.1 Dealing with request and response headers:

HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.set("MyRequestHeader", "MyValue");
HttpEntity<?> requestEntity = new HttpEntity(requestHeaders);

HttpEntity<String> response = template.exchange("http://example.com/hotels/{hotel}",
HttpMethod.GET, requestEntity, String.class, "42");

String responseHeader = response.getHeaders().getFirst("MyResponseHeader") ;
String body = response.getBody();

This example shows the HttpMethod.GET call with a HttpEntity argument being passed in.

Am I doing something wrong here? Again can a method on a controller be of type RequestMethod.GET and utilize and HttpEntity argument?

[Julian Reschke]

From an HTTP point of view, this would mean sending a GET request with a request body. I wouldn't recommend trying that, although it's technically possible. But it *will* confuse lots of components.

(Sending headers with GET of course is ok)

[rence1005]

So is there any recommended way to pass in a custom object as an argument for a GET controller method? The functionality of the method I originally posted uses data out of the argument CustomPersonClass in order to retrieve data from a database. To me, this fits in line with a GET request.