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、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>
 
2、配置web.xml
<?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/hessianapp/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/hessianapp/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/hessianapp/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