resin Hessian Service

Writing a Hessian service as a plain-old Java object (POJO) eliminates protocol dependencies and simplifies service testing.

tutorial demo.jsp

The addition example built the Hessian service as an extension of HessianService for simplicity. Most services will want to be independent of the Hessian protocol itself.

Interface for the math service. The main service implementation. Configures the environment Client JSP

The MathService implementation is just a Java class that implements the MatchService API.

package example; public class MathServiceImpl implements MathService { public int add(int a, int b) { return a + b; } }

The Java interface describes the remote API. This example has an addition method, .

Resin's proxy client implementation uses the remote interface to expose the API to the proxy stub. Strictly speaking, though, the Java remote interface is not required for Hessian. A non-Java client will not use the Java interface, except possibly as documentation.

package example; public interface MathService { public int add(int a, int b); }
<servlet servlet-name="hessian" servlet-class="com.caucho.hessian.server.HessianServlet"> <init-param service-class="example.MathServiceImpl"/> <init-param api-class="example.MathService"/> </servlet>

The client is identical to the basic example.

<%@ page import="com.caucho.hessian.client.HessianProxyFactory" %> <%@ page import="example.MathService" %> <% HessianProxyFactory factory = new HessianProxyFactory(); // http://localhost:8080/resin-doc/protocols/tutorial/hessian-service/hessian/math String url = ("http://" + request.getServerName() + ":" + request.getServerPort() + request.getContextPath() + "/hessian/math"); MathService math = (MathService) factory.create(MathService.class, url); out.println("3 + 2 = " + math.add(3, 2)); %> 3 + 2 = 5