一个简单的hession实例

 

由于本人刚开始接触hession，还未深入的了解hession，所以一下的代码没有注释。

 

 

使用工具 : eclipse 3.3   tomcat 6.0.21   JDK 1.6

jar包：hessian-4.0.7.jar(见附件)

 

1、在 eclipse 中新建一个 Dynamic Web Project，名为 hession

2、在src下建包：com.hession

3、创建的代码如下：

 

package com.hession;

import java.io.Serializable;

public class Car implements Serializable {

	/**
	 * 
	 */
	private static final long serialVersionUID = -8470305814077115888L;

	private String color;
	private String length;
	private String name;
	
	public String toString(){
		StringBuffer buf = new StringBuffer();
		
		buf.append("[Car:{name=").append(getName());
		buf.append(",color=").append(getColor());
		buf.append(",length=").append(getLength());
		
		buf.append("}]");
		
		return buf.toString();
	}
	
	//这里省略 setter()/getter()
}

 

接口：

package com.hession;

public interface IBasic {

	public String hello();
	
	public Car getCar();
}

 

接口的实现类

 

package com.hession;

public class BasicService implements IBasic {
	
	private String hello = "hello,world!";

	@Override
	public Car getCar() {
		Car car = new Car();   
        car.setColor("RED红色");   
        car.setLength("2400");   
        car.setName("HAHACHE");   
        return car;
	}

	@Override
	public String hello() {
		return hello;
	}

}

 

测试：

package com.hession;

import java.net.MalformedURLException;

import com.caucho.hessian.client.HessianProxyFactory;

public class BasicClient {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		String url = "http://localhost:8080/hession/hello";
		HessianProxyFactory f = new HessianProxyFactory();
		try {
			IBasic basic = (IBasic)f.create(IBasic.class, url);
			Car car = basic.getCar();
			System.out.println("hello:"+basic.hello());
			System.out.println(car);
			
		} catch (MalformedURLException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

 

f.create(IBasic.class, url)中，第一个参数必须是接口，不能是实现类。

url 中的端口号以自己 tomcat 中配置的端口号为准。

 

web.xml

<servlet>
		<servlet-name>hello</servlet-name>
		<servlet-class>
			com.caucho.hessian.server.HessianServlet
		</servlet-class>
		<init-param>
			<param-name>home-class</param-name>
			<param-value>com.hession.BasicService</param-value>
		</init-param>
		<init-param>
			<param-name>home-api</param-name>
			<param-value>com.hession.IBasic</param-value>
		</init-param>
	</servlet>
	<servlet-mapping>
		<servlet-name>hello</servlet-name>
		<url-pattern>/hello</url-pattern>
	</servlet-mapping>

 

4、测试步骤

 

如果此时直接运行 BasicClient 类中的main方法，将会出现以下的异常：

 

com.caucho.hessian.client.HessianRuntimeException: java.net.ConnectException: Connection refused: connect
	at com.caucho.hessian.client.HessianProxy.sendRequest(HessianProxy.java:268)
	at com.caucho.hessian.client.HessianProxy.invoke(HessianProxy.java:170)
	at $Proxy0.getCar(Unknown Source)
	at com.hession.BasicClient.main(BasicClient.java:17)
Caused by: java.net.ConnectException: Connection refused: connect
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
	at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
	at java.net.Socket.connect(Socket.java:529)
	at java.net.Socket.connect(Socket.java:478)
	at sun.net.NetworkClient.doConnect(NetworkClient.java:163)
	at sun.net.www.http.HttpClient.openServer(HttpClient.java:394)
	at sun.net.www.http.HttpClient.openServer(HttpClient.java:529)
	at sun.net.www.http.HttpClient.<init>(HttpClient.java:233)
	at sun.net.www.http.HttpClient.New(HttpClient.java:306)
	at sun.net.www.http.HttpClient.New(HttpClient.java:323)
	at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:860)
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:801)
	at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:726)
	at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:904)
	at com.caucho.hessian.client.HessianURLConnection.getOutputStream(HessianURLConnection.java:94)
	at com.caucho.hessian.client.HessianProxy.sendRequest(HessianProxy.java:266)
	... 3 more

 

原因是我们还没有启动 tomcat server。

 

4.1 将工程 hession 添加到 eclipse 中的 tomcat server(见附件中的图片 1.bmp)     

4.2 启动 tomcat server

4.3 运行 BasicClient 类中的main方法

运行成功，运行结果如下:

hello:hello,world!
[Car:{name=HAHACHE,color=RED红色,length=2400}]

 

 

 

评论

1 楼 xurichusheng 2011-11-03  

IBasic basic = (IBasic)f.create(IBasic.class, url); 
Car car = basic.getCar(); 
System.out.println("hello:"+basic.hello()); 

为什么我们这里 create 的是 接口 IBasic，但是运行结果说明是调用实现类BasicService呢？
通过查看 com.caucho.hessian.server.HessianServlet 中的init(ServletConfig config)源码，我们发现：
1、首先取得web.xml中配置的home-class和home-api所对应的类、接口
if(getInitParameter("home-class") != null)
{
        String className = getInitParameter("home-class");
        Class homeClass = loadClass(className);
        _homeImpl = homeClass.newInstance();
        init(_homeImpl);
}

if(getInitParameter("home-api") != null)
{
       String className = getInitParameter("home-api");
        _homeAPI = loadClass(className);
}

2、将实现类和接口的对应关系作映射
if(_homeImpl != null)
{
       _homeAPI = findRemoteAPI(_homeImpl.getClass());
       if(_homeAPI == null)
             _homeAPI = _homeImpl.getClass();
}