Spring - Support for Hessian binary web service and client

In Spring servlet based web application, we can transparently expose our Java interface based services using Hessian binary HTTP-based protocol. Let's see an example to understand how to do that. We are going to develop two projects; one for the server and other for the client.

Hessian server example

Service Interface

public interface OrderService {

  void placeOrder(String item, int quantity);

  List<Order> getOrderList();

}

public class Order implements Serializable {
  private String item;
  private int qty;
  private Date orderDate;
  //getters/setters
}

Service implementation

public class OrderServiceImpl implements OrderService {
  private List<Order> orders = new ArrayList<>();

  @Override
  public void placeOrder(String item, int quantity) {
      Order order = new Order();
      order.setItem(item);
      order.setQty(quantity);
      order.setOrderDate(new Date());
      System.out.println("placing order: " + order);
      orders.add(order);
  }

  @Override
  public List<Order> getOrderList() {
      return new ArrayList<>(orders);
  }
}

Registering HessianServiceExporter

@EnableWebMvc
@Configuration
public class AppConfig {

  @Bean
  public OrderService orderService() {
      return new OrderServiceImpl();
  }

  @Bean(name = "/OrderService")
  public HessianServiceExporter exporter() {
      HessianServiceExporter hse = new HessianServiceExporter();
      hse.setService(orderService());
      hse.setServiceInterface(OrderService.class);
      return hse;
  }
}

Note that, we registered HessianServiceExporter with name '/OrderService'; this name will be used as the URI of the exposed service.

mvn tomcat7:run-war

Server Project

Dependencies and Technologies Used:

• spring-webmvc 4.3.8.RELEASE: Spring Web MVC.
• hessian 4.0.38: Hessian is a compact binary protocol for connecting web services.
• javax.servlet-api 3.1.0 Java Servlet API
• JDK 1.8
• Maven 3.3.9

Hessian service client

For the client project, we will be using same OrderService interface. A proxy implementation of the service will be provided by HessianProxyFactoryBean.

A bean accessing the remote service

public class OrderBean {

  @Autowired
  private OrderService orderService;

  public void placeOrder() {
      System.out.println("-- placing orders --");
      orderService.placeOrder("ABC Tablet", 2);
      orderService.placeOrder("XYZ Desktop", 3);
  }

  public void listOrders() {
      System.out.println("-- getting order list from service --");
      List<Order> orderList = orderService.getOrderList();
      System.out.println(orderList);
  }
}

Registering HessianProxyFactoryBean and running the client

@Configuration
public class ExampleClient {

  @Bean
  public OrderBean orderBean() {
      return new OrderBean();
  }

  @Bean
  public HessianProxyFactoryBean exporter() {
      HessianProxyFactoryBean b = new HessianProxyFactoryBean();
      b.setServiceUrl("http://localhost:8080/OrderService");
      b.setServiceInterface(OrderService.class);
      return b;
  }

  public static void main(String[] args) {
      AnnotationConfigApplicationContext context =
              new AnnotationConfigApplicationContext(ExampleClient.class);
      OrderBean bean = context.getBean(OrderBean.class);
      bean.placeOrder();
      bean.listOrders();
  }
}

Output

-- placing orders --
-- getting order list from service --
[Order{item='ABC Tablet', qty=2, orderDate=Mon Jun 12 21:23:57 CDT 2017}, Order{item='XYZ Desktop', qty=3, orderDate=Mon Jun 12 21:23:57 CDT 2017}, Order{item='ABC Tablet', qty=2, orderDate=Mon Jun 12 21:24:05 CDT 2017}, Order{item='XYZ Desktop', qty=3, orderDate=Mon Jun 12 21:24:05 CDT 2017}]

Client Project

Dependencies and Technologies Used:

• spring-webmvc 4.3.8.RELEASE: Spring Web MVC.
• hessian 4.0.38: Hessian is a compact binary protocol for connecting web services.
• JDK 1.8
• Maven 3.3.9