云服务器探讨 2010-03-18
/**
*@version1.1
*@createMar18,2010
*/
Hessian是一个轻量级的remotingonhttp工具,使用简单的方法提供了RMI(RemoteMethodInvocation,远程方法调用)的功能。采用的是二进制RPC(RemoteProcedureCallProtocol,远程过程调用协议)协议,因为采用的是二进制协议,所以它很适合于发送二进制数据。
在进行基于Hessian的项目开发时,应当注意以下几点:
▲JAVA服务器端必须具备以下几点:
•包含Hessian的jar包。
•设计一个接口,用来给客户端调用。
•实现该接口的功能。
•配置web.xml,配好相应的servlet。
•对象必须实现Serializable接口。
•对于复杂对像可以使用Map的方法传递。
▲客户端必须具备以下几点:
•java客户端包含Hessian.jar的包。
•具有和服务器端结构一样的接口。
•利用HessianProxyFactory调用远程接口。
下面是一个hessian的简单例子。
Java服务器端:
环境:j2sdk1.4.2、Tomcat6.0
依赖的包:hessian-3.1.6.jar
新建一个名为HessianServer的webproject。将hessian-3.1.6.jar放入WEB-INF/lib文件夹中。
创建接口:
package server.demo; public interface DemoApi { public void setName(String name); public String sayHello(); public User getUser(); }
实现接口:
package server.demo; public class DemoService implements DemoApi { private String name; public String sayHello() { return "Hello "+name; } public void setName(String name) { this.name=name; System.out.println("Hello "+name); } public User getUser() { return new User("lingling", "pass"); } }
创建User类,注意:一定要implementsSerializable。
package server.demo; import java.io.Serializable; public class User implements Serializable { String name = "kitty"; String password = "nopass"; public User() { super(); } public User(String name, String password) { super(); this.name = name; this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
配置web.xml:
<servlet> <servlet-name>first</servlet-name> <servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class> <init-param> <param-name>service-class</param-name> <param-value>server.demo.DemoService</param-value> </init-param> </servlet> <servlet-mapping> <servlet-name>first</servlet-name> <url-pattern>/helloworld</url-pattern> </servlet-mapping>
将项目发布到tomcat服务器上。
Java客户端:
环境:j2sdk1.4.2
依赖的包:hessian-3.1.6.jar
创建一个名为HessianClient的javaproject,载入hessian-3.1.6.jar。
创建与服务器一样的接口及User类,注意它们所在的包路径也要与服务器相同,否则会出现java.lang.ClassNotFoundException。
接口:
package server.demo; public interface DemoApi { public void setName(String name); public String sayHello(); public User getUser(); }
User类:
package server.demo; import java.io.Serializable; public class User implements Serializable { String name = "kitty"; String password = "nopass"; public User() { super(); } public User(String name, String password) { super(); this.name = name; this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } }
客户端程序:
package client.demo; import java.net.MalformedURLException; import server.demo.DemoApi; import com.caucho.hessian.client.HessianProxyFactory; public class ClientTest { public static void main(String[] args) throws MalformedURLException, ClassNotFoundException { String url = "http://localhost:9520/HessianServer/helloworld"; HessianProxyFactory factory = new HessianProxyFactory(); DemoApi api = (DemoApi) factory.create(url); api.setName("test"); System.out.println(api.sayHello()); System.out.println(api.getUser().getName()); System.out.println(api.getUser().getPassword()); } }
现在,启动tomcat,运行ClientTest。运行结果:
Hellotest
lingling
pass
现在,在以上基础上将hessian与spring整合。
Java服务器端(即我们上面建的名为HessianServer的webproject):
环境:j2sdk1.4.2、Tomcat6.0
依赖的包:
1.Hessian包:hessian-3.1.6.jar
2.spring-framework-2.0.2包:
a)aopalliance.jar
b)commons-logging.jar
c)log4j-1.2.14.jar
d)spring.jar
e)spring-aop.jar
f)spring-beans.jar
g)spring-context.jar
h)spring-core.jar
i)spring-jdbc.jar
j)spring-jms.jar
k)spring-web.jar
l)spring-webmvc.jar
配置web.xml,web.xml中增加:
<servlet> <servlet-name>remote</servlet-name> <servlet-class> org.springframework.web.servlet.DispatcherServlet </servlet-class> <init-param> <param-name>namespace</param-name> <param-value>classes/remote-servlet</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>remote</servlet-name> <url-pattern>/remote/*</url-pattern> </servlet-mapping>
写spring的发布hessian服务的配置文件remote-servlet.xml,这个文件就建在工程的src下,即deploy到tomcat后,在WEB-INF/classes目录下。注意:这个文件为什么叫remote-servlet.xml呢?因为我们在web.xml中有配置:<param-value>classes/remote-servlet</param-value>所以文件名为remote-servlet.xml。
以下是remote-servlet.xml的内容:
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> <beans> <bean id="demoService" class="server.demo.DemoService" /> <bean name="/helloSpring" class="org.springframework.remoting.caucho.HessianServiceExporter"> <property name="service" ref="demoService" /> <property name="serviceInterface" value="server.demo.DemoApi" /> </bean> </beans>
好了,现在可以测试一下了。在刚才建的名为HessianClient的javaproject中修改client.demo.ClientTest.java如下:
package client.demo; import java.net.MalformedURLException; import server.demo.DemoApi; import com.caucho.hessian.client.HessianProxyFactory; public class ClientTest { public static void main(String[] args) throws MalformedURLException, ClassNotFoundException { // String url = "http://localhost:9520/HessianServer/helloworld"; String url = "http://localhost:9520/HessianServer/remote/helloSpring"; HessianProxyFactory factory = new HessianProxyFactory(); DemoApi api = (DemoApi) factory.create(DemoApi.class, url); api.setName("test"); System.out.println(api.sayHello()); System.out.println(api.getUser().getName()); System.out.println(api.getUser().getPassword()); } }
现在,启动tomcat,运行ClientTest。运行结果:
Hellotest
lingling
pass
如果客户端也使用spring呢?现在做一个spring整合hessian的客户端demo。首先载入spring-framework-2.0.2包:
1)aopalliance.jar
2)commons-logging.jar
3)log4j-1.2.14.jar
4)spring.jar
5)spring-aop.jar
6)spring-beans.jar
7)spring-context.jar
8)spring-core.jar
9)spring-jdbc.jar
10)spring-jms.jar
11)spring-web.jar
12)spring-webmvc.jar
在名为HessianClient的javaproject中src目录下,新建一个remote-client.xml,这个文件可随意命名。remote-client.xml内容为:
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> <beans> <bean id="helloSpring" class="org.springframework.remoting.caucho.HessianProxyFactoryBean"> <property name="serviceUrl"> <value> http://localhost:9520/HessianServer/remote/helloSpring </value> </property> <property name="serviceInterface"> <value>server.demo.DemoApi</value> </property> </bean> </beans>
在刚才建的名为HessianClient的javaproject中修改client.demo.ClientTest.java如下:
package client.demo; import java.net.MalformedURLException; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import server.demo.DemoApi; public class ClientTest { public static void main(String[] args) throws MalformedURLException, ClassNotFoundException { // String url = "http://localhost:9520/HessianServer/helloworld"; // String url = // "http://localhost:9520/HessianServer/remote/helloSpring"; // HessianProxyFactory factory = new HessianProxyFactory(); // DemoApi api = (DemoApi) factory.create(DemoApi.class, url); ApplicationContext context = new ClassPathXmlApplicationContext( "remote-client.xml"); DemoApi api = (DemoApi) context.getBean("helloSpring"); api.setName("test"); System.out.println(api.sayHello()); System.out.println(api.getUser().getName()); System.out.println(api.getUser().getPassword()); } }
现在,启动tomcat,运行ClientTest。运行结果:
Hellotest
lingling
pass
至此over~
PS:有时候可能因hessian或spring的版本问题使程序不能运行