import org.jboss.resteasy.core.Headers; //导入依赖的package包/类
public static <T> T getEntity(ClientMessage msg, Class<T> type, Type genericType, ResteasyProviderFactory factory) {
   int size = msg.getBodySize();
   if (size <= 0)
      return null;

   byte[] body = new byte[size];
   msg.getBodyBuffer().readBytes(body);

   String contentType = msg.getStringProperty(HttpHeaderProperty.CONTENT_TYPE);
   if (contentType == null) {
      throw new UnknownMediaType("Message did not have a Content-Type header cannot extract entity");
   }
   MediaType ct = MediaType.valueOf(contentType);
   MessageBodyReader<T> reader = factory.getMessageBodyReader(type, genericType, null, ct);
   if (reader == null) {
      throw new UnmarshalException("Unable to find a JAX-RS reader for type " + type.getName() + " and media type " + contentType);
   }

   Providers current = ResteasyProviderFactory.getContextData(Providers.class);
   ResteasyProviderFactory.pushContext(Providers.class, factory);
   try {
      return reader.readFrom(type, genericType, null, ct, new Headers<String>(), new ByteArrayInputStream(body));
   } catch (IOException e) {
      throw new RuntimeException(e);
   } finally {
      ResteasyProviderFactory.popContextData(Providers.class);
      if (current != null)
         ResteasyProviderFactory.pushContext(Providers.class, current);
   }
}