学习Hessian-1

创建Hessian服务接口

1、创建一个maven项目



2、在pom中加入相关依赖

无

3、创建Service接口

package org.didinem.service;

/**
* Created by didinem on 16-5-21.
*/
public interface IHessianService {
public String serviceMethod(String name);
}

4、maven install

搭建Hessian服务端

Hessian官方对于Hessian服务的说明

The Hessian library makes it possible to write services by extending HessianServlet.

Any public method is treated as a service method. So adding new methods is as easy as writing a normal Java class.

Because the service is implemented as a Servlet, it can use all the familiar servlet data in the ServletContext, just like a normal servlet.

简单来说，如果自己想要实现一个Hessian的服务，只要继承HessianServlet，然后这个类所有的public方法就可以当作是Hessian服务的方法了。（那能不能排除指定的public method呢？）

1.创建maven web项目



2.引入相关依赖

<dependency>
<groupId>com.caucho</groupId>
<artifactId>hessian</artifactId>
<version>4.0.7</version>
</dependency>
<dependency>
<groupId>org.didinem</groupId>
<artifactId>hessian-api</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>

3、实现Hessian服务

/**
* Created by didinem on 16-5-21.
*/
public class HessianServiceImpl extends HessianServlet implements IHessianService {
@Override
public String serviceMethod(String name) {
return "Hello " + name;
}
}

4、配置Hessian服务

Since the HessianServlet is a standard servlet, it can also be configured in the standard servlet configuration.

配置Hessian服务就是配置Servlet

<servlet>
<servlet-name>hessianService</servlet-name>
<servlet-class>HessianServiceImpl</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>hessianService</servlet-name>
<url-pattern>/hessianService</url-pattern>
</servlet-mapping>

5、配置并启动tomcat











这里的hessian-demo-server:war和hessian-demo-server:war exploded的区别猜测如下（待验证）：

前者是把web工程打成一个war包部署到tomcat，而后者只是把web工程的目录拷贝到了tomcat的webapps下。



启动tomcat，访问地址http://localhost:8080/hessian-demo-server/hessianService

当页面出现如下图类似内容时，代表服务至少部署成功，能不能用就再说了

搭建Hessian客户端来测试

1、创建maven项目

2、引入相关依赖

<dependency>
<groupId>com.caucho</groupId>
<artifactId>hessian</artifactId>
<version>4.0.7</version>
</dependency>
<dependency>
<groupId>org.didinem</groupId>
<artifactId>hessian-demo-api</artifactId>
<version>1.0-SNAPSHOT</version>
</dependency>

3、编写客户端

Hessian官方对于客户端的说明

Using a Hessian service from a Java client is like calling a method. The HessianProxyFactory creates proxies which act like normal Java objects, with possibility that the method might throw a protocol exception if the remote connection fails. Using HessianProxyFactory requires JDK 1.3.

Each service will have a normal Java interface describing the service. The trivial hello, world example just returns a string. Because the Hessian services support Java serialization, any Java type can be used.

简单来说通过HessianProxyFactory获得服务的代理，然后像调用普通方法一样调用Hessian服务。

官方给出的样例：

package example;

import com.caucho.hessian.client.HessianProxyFactory;

public class BasicClient {
public static void main(String []args) throws Exception {
String url = "http://www.caucho.com/hessian/test/basic";
HessianProxyFactory factory = new HessianProxyFactory();
Basic basic = (Basic) factory.create(Basic.class, url);
System.out.println("Hello: " + basic.hello());
}
}

那这样就很简单了

package org.didinem.client;

import com.caucho.hessian.client.HessianProxyFactory;
import org.didinem.service.IHessianService;

/**
* Created by didinem on 16-5-22.
*/
public class HessianClient {
public static void main(String[] args) {
String url = "http://localhost:8080/hessian-demo-server/hessianService";

HessianProxyFactory factory = new HessianProxyFactory();
IHessianService hessianService = (IHessianService) factory.create(IHessianService.class, url);

System.out.println(hessianService.serviceMethod("hehe"));
}
}

执行输出结果：