@PathParam, @QueryParam, @MatrixParam, @FormParam, and @HeaderParam are represented as strings in a raw HTTP request. The specification says that these types of injected parameters can be converted to objects if these objects have a valueOf(String) static method or a constructor that takes one String parameter. What if you have a class where valueOf() or this string constructor doesn't exist or is inappropriate for an HTTP request? Resteasy has 2 proprietary @Provider interfaces that you can plug in:

package org.jboss.resteasy.spi;

public interface StringConverter<T>
{
   T fromString(String str);
   String toString(T value);
}



   

   import org.jboss.resteasy.client.ProxyFactory;
   import org.jboss.resteasy.spi.StringConverter;
   import org.jboss.resteasy.test.BaseResourceTest;
   import org.junit.Assert;
   import org.junit.Before;
   import org.junit.Test;

   import javax.ws.rs.HeaderParam;
   import javax.ws.rs.MatrixParam;
   import javax.ws.rs.PUT;
   import javax.ws.rs.Path;
   import javax.ws.rs.PathParam;
   import javax.ws.rs.QueryParam;
   import javax.ws.rs.ext.Provider;

   public class StringConverterTest extends BaseResourceTest
   {
      public static class POJO
      {
         private String name;

         public String getName()
         {
            return name;
         }

         public void setName(String name)
         {
            this.name = name;
         }
      }

      @Provider
      public static class POJOConverter implements StringConverter<POJO>
      {
         public POJO fromString(String str)
         {
            System.out.println("FROM STRNG: " + str);
            POJO pojo = new POJO();
            pojo.setName(str);
            return pojo;
         }

         public String toString(POJO value)
         {
            return value.getName();
         }
      }

      @Path("/")
      public static class MyResource
      {
         @Path("{pojo}")
         @PUT
         public void put(@QueryParam("pojo")POJO q, @PathParam("pojo")POJO pp,
                         @MatrixParam("pojo")POJO mp, @HeaderParam("pojo")POJO hp)
         {
            Assert.assertEquals(q.getName(), "pojo");
            Assert.assertEquals(pp.getName(), "pojo");
            Assert.assertEquals(mp.getName(), "pojo");
            Assert.assertEquals(hp.getName(), "pojo");
         }
      }

      @Before
      public void setUp() throws Exception
      {
         dispatcher.getProviderFactory().addStringConverter(POJOConverter.class);
         dispatcher.getRegistry().addPerRequestResource(MyResource.class);
      }

      @Path("/")
      public static interface MyClient
      {
         @Path("{pojo}")
         @PUT
         void put(@QueryParam("pojo")POJO q, @PathParam("pojo")POJO pp,
                  @MatrixParam("pojo")POJO mp, @HeaderParam("pojo")POJO hp);
      }

      @Test
      public void testIt() throws Exception
      {
         MyClient client = ProxyFactory.create(MyClient.class, "http://localhost:8081");
         POJO pojo = new POJO();
         pojo.setName("pojo");
         client.put(pojo, pojo, pojo, pojo);
      }
   }

   

package org.jboss.resteasy.spi;

public interface StringParameterUnmarshaller<T>
{
   void setAnnotations(Annotation[] annotations);
   T fromString(String str);
}

public class StringParamUnmarshallerTest extends BaseResourceTest
{
   @Retention(RetentionPolicy.RUNTIME)
   @StringParameterUnmarshallerBinder(DateFormatter.class)
   public @interface DateFormat
   {
      String value();
   }

   public static class DateFormatter implements StringParameterUnmarshaller<Date>
   {
      private SimpleDateFormat formatter;

      public void setAnnotations(Annotation[] annotations)
      {
         DateFormat format = FindAnnotation.findAnnotation(annotations, DateFormat.class);
         formatter = new SimpleDateFormat(format.value());
      }

      public Date fromString(String str)
      {
         try
         {
            return formatter.parse(str);
         }
         catch (ParseException e)
         {
            throw new RuntimeException(e);
         }
      }
   }

   @Path("/datetest")
   public static class Service
   {
      @GET
      @Produces("text/plain")
      @Path("/{date}")
      public String get(@PathParam("date") @DateFormat("MM-dd-yyyy") Date date)
      {
         System.out.println(date);
         Calendar c = Calendar.getInstance();
         c.setTime(date);
         Assert.assertEquals(3, c.get(Calendar.MONTH));
         Assert.assertEquals(23, c.get(Calendar.DAY_OF_MONTH));
         Assert.assertEquals(1977, c.get(Calendar.YEAR));
         return date.toString();
      }
   }

   @BeforeClass
   public static void setup() throws Exception
   {
      addPerRequestResource(Service.class);
   }

   @Test
   public void testMe() throws Exception
   {
      ClientRequest request = new ClientRequest(generateURL("/datetest/04-23-1977"));
      System.out.println(request.getTarget(String.class));
   }
}