How to create/write to file in class namespace under web-inf/class

Question

I concocted the following to cache an Object to a class resource location.

static private <T> void toSerializedCache(Class<T> cls, T t, String cachecrlstr) {
  try {
    URL crl = cls.getResource(cachecrlstr);
    File crf = new File(crl.getFile());

    JAXBContext jaxbContext = JAXBContext.newInstance(cls);
    Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
    jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    jaxbMarshaller.marshal(t, crf);
  }
  catch (Exception e) {
    System.out.printf("Failed to write %s to cache %s", t.getClass(), cachecrlstr);
  }
}

The problem is cachecrlstr is an initially non-existent file. The file has to be initially created.

Since it is initially non-existent, the class loader would return the url as null and the procedure fails.

I cannot use absolute path because this routine runs on a web service where we need to deduce the absolute path from the classloader.

To solve this problem, I rewrite the routine to

static private <T> void toSerializedCache(Class<T> cls, T t, String cachecrlstr) {
  try {
    File crf = new File(request.getSession().getServletContext().getRealPath("/WEB-INF/class"+cachecrlstr));

    JAXBContext jaxbContext = JAXBContext.newInstance(cls);
    Marshaller jaxbMarshaller = jaxbContext.createMarshaller();
    jaxbMarshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    jaxbMarshaller.marshal(t, file);
  }
  catch (JAXBException e) {
    System.out.printf("Failed to write %s to cache %s", t.getClass(), cachecrlstr);
  }
}

But I am unable to obtain the httpservletrequest object because this routine is inside a jax-rs service implementation. And I am unwilling to write a http listener (those registered in web.xml) to store the request into Threadlocal map. (meaning, don't want to muck around maintaining Threadlocal objects).

However, (though unwilling to write to it) I am willing to withdraw objects from Threadlocal.

Does anyone know if RestEasy stores any http objects in Threadlocal that I could withdraw to deduce the session context or request?

More important question is - what do you suggest that I do to write objects to a file, where the file path is relative to WEB-INF/class, under the constraints I stated above.

score 1 · Accepted Answer · answered Jul 16 '12 at 11:19

You can retrieve the HttpServletRequest from ResteasyProviderFactory:

HttpServletRequest request = (HttpServletRequest) ResteasyProviderFactory.getContextDataMap().get(HttpServletRequest.class);

Or if you are inside a JAX-RS service or interceptor, RESTEasy can inject HttpServletRequest for you.

@javax.ws.rs.core.Context
HttpServletRequest request;

How to create/write to file in class namespace under web-inf/class

1 Answers1