Deeply understand the Hessian framework technology in Java class libraries

The Hessian framework is a remote calling technique in Java class libraries that passes object and method calls through serialization and deserialization, making remote method calls more convenient and efficient in distributed environments. So, let's delve deeper into the technical principles of the Hessian framework. Hessian uses the binary RPC protocol to serialize Java objects into byte streams, which are transmitted over the network to another JVM, and deserialized into Java objects on the receiving end, thus achieving cross network method calls. The use of Hessian is very simple. Firstly, we need to introduce Hessian dependencies on both the client and server sides, such as using Maven: <dependency> <groupId>com.caucho</groupId> <artifactId>hessian</artifactId> <version>4.0.59</version> </dependency> On the server side, we need to implement an interface and use the 'HessianServlet' class provided by Hessian to expose the interface as a Servlet for remote calls by the client. For example: public interface HelloService { String sayHello(String name); } public class HelloServiceImpl implements HelloService { @Override public String sayHello(String name) { return "Hello, " + name + "!"; } } //Configuring Servlets in Web.xml <servlet> <servlet-name>HelloServlet</servlet-name> <servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class> <init-param> <param-name>service-class</param-name> <param-value>com.example.HelloServiceImpl</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>HelloServlet</servlet-name> <url-pattern>/hello</url-pattern> </servlet-mapping> Next, we can call the server-side methods on the client side. Firstly, you need to create an instance of 'HessianProxyFactory' and set the URL address of the remote service: String url = "http://localhost:8080/hello"; HessianProxyFactory factory = new HessianProxyFactory(); HelloService service = (HelloService) factory.create(HelloService.class, url); Then, we can directly call the methods of the remote service: String result = service.sayHello("World"); System.out.println(result); In the above example code, we implemented a simple remote call example using the Hessian framework. To summarize, the Hessian framework, as an efficient remote invocation technique, achieves cross network method calls through serialization and deserialization. Using Hessian, we can easily build distributed systems and implement remote service invocation and management through simple method calls.