How to cache response with Jersey?

Question

I am trying to develop restful API using Jersey.I have GET API's for a particular get operation my GET is taking same time from the same client. Is it possible to cache response? Any pointers is appreciated.

Thanks

score 10 · Accepted Answer · answered Feb 26 '13 at 11:32

You can use CacheControl, eTag - follow below example code

// In your jersey method
    final EntityTag eTag = new EntityTag(resource.getId() + "_" +
     resource.getLastModified().getTime());
    final CacheControl cacheControl = new CacheControl();
    cacheControl.setMaxAge(-1);

    ResponseBuilder builder = request.evaluatePreconditions(
         resource.getLastModified(), eTag);

    // the resoruce's information was modified, return it
    if (builder == null) {
         builder = Response.ok(resource);
    }

    // the resource's information was not modified, return a 304

    return builder.cacheControl(cacheControl).lastModified(
         resource.getLastModified()).tag(eTag).build();

Replace resource with your Resource instance.

Would u mind explaining why u disable Cache-Control (no-cache)? Its like telling: sry no caching possible but look here I have a useless Etag and Last-Modified headers. — Orri, Nov 12 '13 at 17:50
it is to say, its cached forever but server can say whether resource is modified based on e-tag , hence client/browser can use it from cache — TheWhiteRabbit, Nov 13 '13 at 09:18

score 8 · Answer 2 · edited Oct 07 '21 at 05:51

Summary of solutions:

Request as method parameter

Interface:

 @Path("myentity")
 public interface MyEntityResource

     @GET
     @Produces(MediaType.APPLICATION_JSON)
     public Response getMyEntity(@Context final Request request);
 }

Implementation:

 public class MyEntityResourceImpl implements MyEntityResource

     @Override
     public Response getMyEntity(final Request request) {

         final MyEntity myEntity = ... // load entity
         final String eTagValue = ... // calclutate value of ETag

         final EntityTag eTag = new EntityTag(eTagValue);

         ResponseBuilder responseBuilder = request.evaluatePreconditions(eTag);

         if (responseBuilder == null) {
             return Response.ok(user).tag(eTag).build();
         }

         return responseBuilder.build();
     }
 }

Disadvantages:

implementation detail Requestis exposed
return type Reponse is generic
missing grammar of return type in WADL
client proxy with unnecessary parameter Request

Request as instance variable

Interface:

 @Path("myentity")
 public interface MyEntityResource

     @GET
     @Produces(MediaType.APPLICATION_JSON)
     public Response getMyEntity();
 }

Implementation:

 public class MyEntityResourceImpl implements MyEntityResource

     @Context
     private Request request

     @Override
     public Response getMyEntity() {

         final MyEntity myEntity = ... // load entity
         final String eTagValue = ... // calclutate value of ETag

         final EntityTag eTag = new EntityTag(eTagValue);

         ResponseBuilder responseBuilder = request.evaluatePreconditions(eTag);

         if (responseBuilder == null) {
             return Response.ok(user).tag(eTag).build();
         }

         return responseBuilder.build();
     }
 }

Disadvantages:

return type Reponse is generic
missing grammar of return type in WADL
dependency injection with @Context is complicated, see https://stackoverflow.com/questions/33240443

ShallowEtagHeaderFilter as web filter

web.xml:

 <filter>
     <filter-name>etagFilter</filter-name>
     <filter-class>org.springframework.web.filter.ShallowEtagHeaderFilter</filter-class>
 </filter>
 <filter-mapping>
     <filter-name>etagFilter</filter-name>
     <url-pattern>/api/*</url-pattern>
 </filter-mapping>

Interface:

 @Path("myentity")
 public interface MyEntityResource

     @GET
     @Produces(MediaType.APPLICATION_JSON)
     public MyEntity getMyEntity();
 }

Implementation:

 public class MyEntityResourceImpl implements MyEntityResource

     @Override
     public MyEntity getMyEntity() {

         final MyEntity myEntity = ... // load entity
         return myEntity;
     }
 }

Disadvantages:

bad server performance, see JavaDoc
works only on uncommitted response
no support of weak ETag

Custom WriterInterceptor as JAX-RS Interceptor

Interceptor:

 public class CustomInterceptor implements WriterInterceptor {

     @Context
     private Request request;

     @Override
     public void aroundWriteTo(WriterInterceptorContext context) throws IOException, WebApplicationException {

         OutputStream old = context.getOutputStream();

         ByteArrayOutputStream buffer = new ByteArrayOutputStream();

         try {

             context.setOutputStream(buffer);
             context.proceed();

             byte[] entity = buffer.toByteArray();

             String etag = ... // calclutate value of ETag
             context.getHeaders().putSingle(HttpHeaders.ETAG, etag);

             ResponseBuilder responseBuilder = request.evaluatePreconditions(eTag);

             if (responseBuilder == null) {
                  throw new WebApplicationException(responseBuilder.status(Response.Status.NOT_MODIFIED).header(HttpHeaders.ETAG, etag).build());
             }

             old.write(entity);

         } finally {
             context.setOutputStream(old);
         }
     }
 }

See also: ServerCacheInterceptor (Resteasy)

Interface:

 @Path("myentity")
 public interface MyEntityResource

     @GET
     @Produces(MediaType.APPLICATION_JSON)
     public MyEntity getMyEntity();
 }

Implementation:

 public class MyEntityResourceImpl implements MyEntityResource

     @Override
     public MyEntity getMyEntity() {

         final MyEntity myEntity = ... // load entity
         return myEntity;
     }
 }

Disadvantages:

no predefined interceptor for Jersey available
bad server performance
no support of weak ETag
ugly workaround with WebApplicationException

flash · Answer 3 · 2013-02-26T11:38:32.333

You could use any caching mechanism applicable for standard java together with Jersey, like Ehcache.

You only have to pay attention to verify that your data in the backend hasn't changed.

Here is simple example with Ehcache:

@GET
@Path("{id}")
public List<Data> getData(@PathParam("id") Long id) {
    Element element = CacheManager.getInstance().getCache("test").get(id);
    if(element == null) {
        Data value = fetchElementFromBackend(id);
        CacheManager.getInstance().getCache("test").put(new Element(id, value));
        return value;
    }

    return element.getObjectValue();
}

Andrey Lebedenko · Answer 4 · 2020-07-27T08:43:14.077

1

Recently I've been solving a similar (if not the same) problem. As a side result of it the following library emerged: https://github.com/AndreyLebedenko/dropwizard-caching-filter

The way it can be used is like below:

@GET
@Produces(MediaType.APPLICATION_JSON)
@Path("/cached")
@ResponseCachedByFilter(10000)
public Object getCached() {
    return dao.get();
}

Hope it helps.

edited Jul 27 '20 at 08:43

answered Nov 10 '18 at 19:43

Andrey Lebedenko

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How to cache response with Jersey?

4 Answers4