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