Spring整合Hessian

Spring让Hessian变得不但强大,而且易用,但是易用背后,却有不少陷阱!
 
这个例子很简单,但实际上的确花费了我超过一小时的时间,排除了种种问题,最后问题终于水落石出。
 
整合以上篇Hello Hessian为基础,加入Spring框架,进行改进。
 
一、环境
jdk1.5
 
顺便说下,如果不说环境版本,很难保证你的程序在别的版本下能运行。
 
二、整合
1、服务器端代码: Hello接口, 同时也是需要远程暴露的接口

  
  1. package lavasoft.suths.service; 
  2.  
  3. /** 
  4.  * 一个简单的服务接口 
  5.  * 
  6.  * @author leizhimin 2009-8-14 11:45:03 
  7.  */ 
  8. public interface Hello { 
  9.     String sayHello(String name); 
2、服务器端代码,服务器的实现类, 不需要暴露给客户端

  
  1. package lavasoft.suths.service; 
  2.  
  3. public class HelloService implements Hello { 
  4.     public String sayHello(String name) { 
  5.         System.out.println("welcome you, " + name); 
  6.         return "welcome you, " + name + "!"
  7.     } 
 3、写Spring的发布Hessian服务的配置文件
 hessian-servlet.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> 
< beans > 
         < bean  id ="defaultHandlerMapping"  class ="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping" /> 
         < bean  id ="helloService"  class ="lavasoft.suths.service.HelloService" /> 
         < bean  name ="/hello"  class ="org.springframework.remoting.caucho.HessianServiceExporter" > 
                 < property  name ="service"  ref ="helloService" /> 
                 < property  name ="serviceInterface"  value ="lavasoft.suths.service.Hello" /> 
         </ bean > 
</ beans >
 
4、配置web.xml, 让服务器在启动的时候加载hessian的远程类
<? xml  version ="1.0"  encoding ="UTF-8" ?> 
< web-app  xmlns ="http://java.sun.com/xml/ns/javaee" 
                  xmlns:xsi ="http://www.w3.org/2001/XMLSchema-instance" 
                 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
        http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
                  version ="2.5" > 
         < context-param > 
                 < param-name >contextConfigLocation </ param-name > 
                 < param-value > 
                        /WEB-INF/hessian-servlet.xml 
                 </ param-value > 
         </ context-param > 
         < servlet > 
                 < servlet-name >hessian </ servlet-name > 
                 < servlet-class >org.springframework.web.servlet.DispatcherServlet </ servlet-class > 
                 < load-on-startup >4 </ load-on-startup > 
         </ servlet > 

         < servlet-mapping > 
                 < servlet-name >hessian </ servlet-name > 
                 < url-pattern >/hessian/* </ url-pattern > 
         </ servlet-mapping > 
</ web-app >
 
陷阱:
a)hessian-servlet.xml的文件名必须以<servlet-name>hessian</servlet-name>名字开头,并且加上-servlet.xml一段,组成完整的文件名。
b)hessian-servlet.xml的文件名格式必须是[servlet-name]-servlet.xml格式,否则出错。
 
三、部署应用
 
因为涉及到类加载顺序问题,好用IDEA启动Tomcat测试老失败,不知道为啥!这次不用IDEA嵌入式启动Tomcat了,直接自己部署测试。
部署后,启动界面如下:
 
三、写测试
 
这次测试,可以在上个例子的基础上进行修改来测试,根据上面的配置,那么请求HelloService的URL应该是: http://localhost:8080/hession.web/hessian/hello
package lavasoft.suths.service.client; 

import com.caucho.hessian.client.HessianProxyFactory; 
import lavasoft.suths.service.Hello; 

import java.net.MalformedURLException; 

/** 
* 客户端调用(会依赖服务接口) 

* @author leizhimin 2009-8-14 12:29:33 
*/
 
public  class Client { 
         public  static  void main(String[] args)  throws MalformedURLException { 
                String url =  "http://localhost:8080/hession.web/hessian/hello"; 
                HessianProxyFactory factory = new HessianProxyFactory(); 
                Hello hello = (Hello) factory.create(Hello.class, url); 
                System.out.println(hello.sayHello("Hessian")); 
        } 
}
 
运行结果:
Hello Hessian! 

Process finished with exit code 0
 
还有一种测试方法,就是在客户端也使用Spring,需要做个配置remoting-client.xml:
<!DOCTYPE beans PUBLIC  "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"> 
<beans> 
        <bean id="helloServiceClient" class="org.springframework.remoting.caucho.HessianProxyFactoryBean"
                <property name="serviceUrl" value="http://localhost:8080/hession.web/hessian/hello"/> 
                <property name="serviceInterface" value="lavasoft.suths.service.Hello"/> 
        </bean> 
</beans>
 
然后写个测试类:
package lavasoft.suths.service.client; 

import lavasoft.suths.service.Hello; 
import org.springframework.context.ApplicationContext; 
import org.springframework.context.support.ClassPathXmlApplicationContext; 

/** 
* Spring整合Hessian,客户端测试 

* @author leizhimin 2009-8-14 15:32:46 
*/
 
public  class TestClient { 
         public  static  void main(String[] args) { 
                 try { 
                        ApplicationContext context =  new ClassPathXmlApplicationContext( "/remoting-client.xml"); 
                        Hello hello = (Hello) context.getBean( "helloServiceClient"); 
                        System.out.println(hello.sayHello( "Spring Hession")); 
                } 
                 catch (Exception e) { 
                        e.printStackTrace(); 
                } 
        } 
}
 
运行结果:
Hello Spring Hession! 

Process finished with exit code 0
 
陷阱:
实际上,看着代码好好,程序有时候还是不能跑,原因是Hessian的版本问题,这里推荐使用Spring自带的版本,就不会有问题了。
 
整个工程所以依赖的包:
log4j-1.2.15.jar 
spring-aop.jar 
spring-beans.jar 
spring-context.jar 
spring-context-support.jar 
spring-core.jar 
spring-jdbc.jar 
spring-jms.jar 
spring-orm.jar 
spring-test.jar 
spring-tx.jar 
spring-web.jar 
spring-webmvc.jar 
spring-webmvc-portlet.jar 
spring-webmvc-struts.jar 
hessian-3.1.3.jar 
aopalliance.jar 
commons-logging.jar
在Maven工程中,加载的依赖为:

   
  1. <dependencies> 
  2.         <dependency> 
  3.             <groupId>com.alibaba.external</groupId> 
  4.             <artifactId>test.junit</artifactId> 
  5.             <version>4.4</version> 
  6.             <scope>test</scope> 
  7.         </dependency> 
  8.         <dependency> 
  9.             <groupId>com.alibaba.external</groupId> 
  10.             <artifactId>sourceforge.spring</artifactId> 
  11.             <version>2.5.6</version> 
  12.         </dependency> 
  13.         <dependency> 
  14.             <groupId>com.alibaba.external</groupId> 
  15.             <artifactId>caucho.hessian</artifactId> 
  16.             <version>3.2.0</version> 
  17.         </dependency> 
  18.         <dependency> 
  19.             <groupId>org.springframework</groupId> 
  20.             <artifactId>spring-web</artifactId> 
  21.             <version>2.5.6</version> 
  22.         </dependency> 
  23.         <dependency> 
  24.             <groupId>org.springframework</groupId> 
  25.             <artifactId>spring-webmvc</artifactId> 
  26.             <version>2.5.6</version> 
  27.         </dependency> 
  28.     </dependencies> 
  29.     <build> 
  30.         <finalName>hession.web</finalName> 
  31.         <plugins> 
  32.             <plugin> 
  33.                 <groupId>org.mortbay.jetty</groupId> 
  34.                 <artifactId>maven-jetty-plugin</artifactId> 
  35.                 <version>6.1.9</version> 
  36.             </plugin> 
  37.         </plugins> 
  38.     </build> 
mvn jetty:run