【RPC框架Hessian一】Hessian RPC Hello World

深碍√TFBOYSˉ_ 2022-08-12 03:29 201阅读 0赞

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2014-09-02 07:15:14

## 什么是Hessian ##

The Hessian binary web service protocol makes web services usable without requiring a large framework, and without learning yet another alphabet soup of protocols. Because it is a binary protocol, it is well-suited to sending binary data without any need to extend the protocol with attachments.

## Hessian版HelloWorld ##

### 1. 创建基于Maven的web项目 ###

### 2. pom.xml ###

<?xml version="1.0" encoding="UTF-8"?>
    <project xmlns="http://maven.apache.org/POM/4.0.0"
    		 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    	<parent>
    		<artifactId>user.project</artifactId>
    		<groupId>com.tom</groupId>
    		<version>1.0-SNAPSHOT</version>
    	</parent>
    	<modelVersion>4.0.0</modelVersion>
    
    	<artifactId>learn.hessian</artifactId>
    
    	<dependencies>
    		<dependency>
    			<groupId>com.caucho</groupId>
    			<artifactId>hessian</artifactId>
    			<version>4.0.38</version>
    		</dependency>
    		<dependency>
    			<groupId>javax.servlet</groupId>
    			<artifactId>javax.servlet-api</artifactId>
    			<version>3.1.0</version>
    			<scope>provided</scope>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			
    			
    			<plugin>
    				<groupId>org.mortbay.jetty</groupId>
    				<artifactId>maven-jetty-plugin</artifactId>
    				<version>6.1.7</version>
    				<configuration>
    					<connectors>
    						<connector implementation="org.mortbay.jetty.nio.SelectChannelConnector">
    							<port>8668</port>
    							<maxIdleTime>30000</maxIdleTime>
    						</connector>
    					</connectors>
    					<webAppSourceDirectory>${project.basedir}/web
    					</webAppSourceDirectory>
    					<contextPath>/web</contextPath>
    				</configuration>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

上面主要配置了三部分内容，一是依赖的Hessian包，二是Hessian依赖的servlet-api包(Hessian包虽然依赖servlet-api，但在Hessian包的依赖关系中并没有显示的去依赖servlet-api包)，三是添加jetty插件，用于启动web项目

### 3.定义服务器和客户端都会依赖的接口service    ###

在HelloWorld中，没有复杂的Model对象，在实际项目中，服务器端和客户端共同依赖的内容包括模型对象和接口Service

package com.tom.hessian.common;
    
    import java.io.IOException;
    
    public interface IGreetingService {
         
        public String greeting(String name) throws IOException;
    }

### 4.定义服务器接口实现 ###

package com.tom.hessian.server;
    
    import com.tom.hessian.common.IGreetingService;
    
    import java.io.IOException;
    
    public class GreetingService implements IGreetingService{
         
        @Override
        public String greeting(String name) throws IOException {
         
            return "Welcome ot the Hassian world, " + name;
        }
    }

### 5. 配置web.xml ###

<?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    		 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    		 xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    		 version="3.1">
    	<servlet>
    		<servlet-name>hessian</servlet-name>
    		<servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>
    		<init-param>
    			<param-name>home-api</param-name>
    			<param-value>com.tom.hessian.common.IGreetingService</param-value>
    		</init-param>
    		<init-param>
    			<param-name>home-class</param-name>
    			<param-value>com.tom.hessian.server.GreetingService</param-value>
    		</init-param>
    		<load-on-startup>1</load-on-startup>
    	</servlet>
    	<servlet-mapping>
    		<servlet-name>hessian</servlet-name>
    		<url-pattern>/hessian</url-pattern>
    	</servlet-mapping>
    </web-app>

### 6.客户端代码 ###

package com.tom.hessian.client;
    
    import com.caucho.hessian.client.HessianProxyFactory;
    import com.tom.hessian.common.IGreetingService;
    
    
    public class GreetingServiceTest {
         
        public static void main(String[] args) throws Exception {
         
    	//RPC访问地址
    	String url = "http://localhost:8668/web/hessian";
    
    	//接口的动态代理工厂
    	HessianProxyFactory factory = new HessianProxyFactory();
    	IGreetingService greetingService = (IGreetingService) factory.create(IGreetingService.class, url);
    
    	//远程方法调用
    	System.out.println("hello(), " + greetingService.greeting("tom"));
        }
    }

### 7.运行 ###

启动jetty服务器，运行客户端main方法，得到如下输出，证明远程方法调用成功

hello, welcome ot the Hassian world, tom