Red Hat Summit Red Hat SummitSupportConsoleDevelopersStart a trialContact

Chapter 22. String marshalling for String based @*Param

@PathParam, @QueryParam, @MatrixParam, @FormParam, and @HeaderParam are represented as Strings in a raw HTTP request. These injected parameter types can be converted into objects if they have a valueOf(String) static method, or a constructor that takes one String parameter. If you have a class with valueOf(), or the String constructor is inappropriate for your HTTP request, you can plug in RESTEasy's proprietary @Provider: 
package org.jboss.resteasy.spi;

public interface StringConverter<T>
{
   T fromString(String str);
   String toString(T value);
}
Copy to Clipboard Toggle word wrap
This interface lets you use your own customized String marshalling. It is registered in web.xml under the resteasy.providers context-param. (See the Installation and Configuration chapter for details.) You can register it manually by calling the ResteasyProviderFactory.addStringConverter() method. A simple example of using the StringConverter follows: 
   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);
      }
   }
Copy to Clipboard Toggle word wrap
Back to top
Red Hat logoGithubredditYoutubeTwitter

Learn

Try, buy, & sell

Communities

About Red Hat Documentation

We help Red Hat users innovate and achieve their goals with our products and services with content they can trust. Explore our recent updates.

Making open source more inclusive

Red Hat is committed to replacing problematic language in our code, documentation, and web properties. For more details, see the Red Hat Blog.

About Red Hat

We deliver hardened solutions that make it easier for enterprises to work across platforms and environments, from the core datacenter to the network edge.

Theme

© 2025 Red Hat