Hessian实现Webservice简单实例

Hessian实现Webservice简单实例

Hessian是一个轻量级的remoting on http工具,采用的是Binary RPC协议，所以它很适合于发送二进制数据,同时又具有防火墙穿透能力。Hessian一般是通过Web应用来提供服务，因此非常类似于平时我们用的WebService。只是它不使用SOAP协议,但相比webservice而言更简单、快捷。

Hessian官网：http://hessian.caucho.com/

Hessian可通过Servlet提供远程服务，需要将匹配某个模式的请求映射到Hessian服务。也可Spring框架整合，通过它的DispatcherServlet可以完成该功能，DispatcherServlet可将匹配模式的请求转发到Hessian服务。Hessian的server端提供一个servlet基类, 用来处理发送的请求，而Hessian的这个远程过程调用，完全使用动态代理来实现的,，建议采用面向接口编程，Hessian服务通过接口暴露。

Hessian处理过程示意图：

客户端——>序列化写到输出流——>远程方法(服务器端)——>序列化写到输出流 ——>客户端读取输入流——>输出结果

下面详细介绍最常用的两种方式实现Hessian提供webservice：

纯Hessian实现

配合Spring框架实现

在开始之前当然需要到官网上下载相关的lib包，放入项目的/WEB-INF/lib/下

【一】、纯Hessian实现步骤：

1.基本代码

首先编写一个服务的接口类：HelloHessian.java

Java代码

 

 

package michael.hessian;
import java.util.List;
import java.util.Map;

/**
 * @author michael
 *
 */
public interface HelloHessian {

    String sayHello();

    MyCar getMyCar();

    List myLoveFruit();

    Map<string, string> myBabays();

}

 

一个java bean文件MyCar.java:

Java代码

 

 

package michael.hessian;

import java.io.Serializable;

/**
 * @author michael
 *
 */
public class MyCar implements Serializable {

    /**
     *
     */
    private static final long serialVersionUID = 4736905401908455439L;

    private String carName;

    private String carModel;

    /**
     * @return the carName
     */
    public String getCarName() {
        return carName;
    }

    /**
     * @return the carModel
     */
    public String getCarModel() {
        return carModel;
    }

    /**
     * @param pCarName the carName to set
     */
    public void setCarName(String pCarName) {
        carName = pCarName;
    }

    /**
     * @param pCarModel the carModel to set
     */
    public void setCarModel(String pCarModel) {
        carModel = pCarModel;
    }

    /**
     * @see java.lang.Object#toString()
     * @return
     */
    @Override
    public String toString() {
        return "my car name:[" + this.carName + "] model:[" + this.carModel
                + "].";
    }

}

 

服务端接口的实现类：HelloHessianImpl.java

Java代码

 

 

package michael.hessian.impl;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import michael.hessian.HelloHessian;
import michael.hessian.MyCar;

/**
 * @author michael
 *
 */
public class HelloHessianImpl extends HessianServlet implements HelloHessian {

    public MyCar getMyCar() {
        MyCar car = new MyCar();
        car.setCarName("阿斯顿·马丁");
        car.setCarModel("One-77");
        return car;
    }

    public Map<string, string> myBabays() {
        Map<string, string> map = new HashMap<string, string>();
        map.put("son", "孙吴空");
        map.put("daughter", "孙小美");
        return map;
    }

    public List myLoveFruit() {
        List list = new ArrayList();
        list.add("apple");
        list.add("kiwi");
        list.add("orange");
        return list;
    }

    public String sayHello() {
        return "welcom to Hessian";
    }

}

2.配置文件web.xml修改

在web.xml配置文件里增加如下信息：

Xml代码

 

 

<servlet>
        <servlet-name>HelloHessianservlet-name>
        <servlet-class>
            com.caucho.hessian.server.HessianServlet
        servlet-class>
        <init-param>
            <param-name>home-classparam-name>
            <param-value>michael.hessian.impl.HelloHessianImplparam-value>
        init-param>
        <init-param>
            <param-name>home-apiparam-name>
            <param-value>michael.hessian.HelloHessianparam-value>
        init-param>
        <load-on-startup>1load-on-startup>
    servlet>
    <servlet-mapping>
        <servlet-name>HelloHessianservlet-name>
        <url-pattern>/HessianServiceurl-pattern>
    servlet-mapping>
    <servlet-mapping>

 

 

 

3.java客户端验证

Java代码

 

 

package michael.hessian.client;

import java.net.MalformedURLException;
import java.util.Map;

import michael.hessian.HelloHessian;
import michael.hessian.MyCar;

import com.caucho.hessian.client.HessianProxyFactory;

/**
 * @author michael
 *
 */
public class HessianClientTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        String url = "http://localhost:8082/J2EE_sjsky/HessianService";
        HessianProxyFactory factory = new HessianProxyFactory();
        try {
            HelloHessian hello = (HelloHessian) factory.create(
                    HelloHessian.class, url);
            System.out.println(hello.sayHello());

            MyCar car = hello.getMyCar();
            System.out.println(car.toString());

            for (Map.Entry<string, string> entry : hello.myBabays().entrySet()) {
                System.out.println(entry.getKey() + "   " + entry.getValue());
            }

            for (String str : hello.myLoveFruit()) {
                System.out.println(str);
            }

        } catch (MalformedURLException e) {
            e.printStackTrace();
        }

    }

}

 

运行结果如下：

Java代码

 

 

welcom to Hessian
my car name:[阿斯顿·马丁] model:[One-77].
daughter   孙小美
son   孙吴空
apple
kiwi
orange

 

【二】、spring+hessian 实现服务端：

1.基本代码见上面的demo

2.修改配置文件

在web.xml，增加内容如下：

Xml代码

 

 

<servlet>
        <servlet-name>springhessianservlet-name>
        <servlet-class>
            org.springframework.web.servlet.DispatcherServlet
        servlet-class>

    <bean name="/helloHessianService"
        class="org.springframework.remoting.caucho.HessianServiceExporter">

        <property name="service" ref="helloHessianImpl" />

        <property name="serviceInterface"
            value="michael.hessian.HelloHessian" />
    bean>
beans>

3.java客户端验证

和上面的例子相似，只需要把访问的url替换成新的即可如下：

Java代码

 

 

String url=http://localhost:8082/J2EE_sjsky/springhessian/helloHessianService

 

运行结果和上面例子一样。

4.spring配置客户端

增加一个spring的bean配置文件hessian-client.xml

Xml代码

xml version="1.0" encoding="UTF-8"?>
>
<beans>
    <bean id="helloHessianClient"
        class="org.springframework.remoting.caucho.HessianProxyFactoryBean">
        <property name="serviceUrl">
            <value>
                http://localhost:8082/J2EE_sjsky/springhessian/helloHessianService
            value>
        property>
        <property name="serviceInterface"
            value="michael.hessian.HelloHessian" />
    bean>
beans>

测试代码HessianSpringClient.java：

Java代码

 

 

package michael.hessian.client;

import java.util.Map;

import michael.hessian.HelloHessian;
import michael.hessian.MyCar;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
 * @author michael
 *
 */
public class HessianSpringClient {

    /**
     * @param args
     */
    public static void main(String[] args) {
        try {
            ApplicationContext context = new ClassPathXmlApplicationContext(
                    "hessian-client.xml");

            HelloHessian hello = (HelloHessian) context
                    .getBean("helloHessianClient");

            System.out.println(hello.sayHello());

            MyCar car = hello.getMyCar();
            System.out.println(car.toString());

            for (Map.Entry<string, string> entry : hello.myBabays().entrySet()) {
                System.out.println(entry.getKey() + "   " + entry.getValue());
            }

            for (String str : hello.myLoveFruit()) {
                System.out.println(str);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}

 

运行结果和上面完全一致。

5.com.caucho.hessian.io.HessianProtocolException: expected string at 0x6d异常处理

我在spring+hessian整合测试过程中，客户端调用时，发生了异常，而服务端错误内容如下：

Java代码

2011-4-25 16:14:44 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet remoting threw exception
com.caucho.hessian.io.HessianProtocolException: expected string at 0x6d
    at com.caucho.hessian.io.Hessian2Input.error(Hessian2Input.java:2882)
    at com.caucho.hessian.io.Hessian2Input.expect(Hessian2Input.java:2830)
    at com.caucho.hessian.io.Hessian2Input.readString(Hessian2Input.java:1362)
    at com.caucho.hessian.io.Hessian2Input.readMethod(Hessian2Input.java:272)
    at com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:249)
    at com.caucho.hessian.server.HessianSkeleton.invoke(HessianSkeleton.java:221)
    at org.springframework.remoting.caucho.Hessian2SkeletonInvoker.invoke(Hessian2SkeletonInvoker.java:67)
    at org.springframework.remoting.caucho.HessianServiceExporter.handleRequest(HessianServiceExporter.java:147)
    at org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter.handle(HttpRequestHandlerAdapter.java:49)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:819)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:754)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:399)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:364)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
    at java.lang.Thread.run(Thread.java:619)

经查资料发现原始是hessian和spring的版本不兼容引起的，重新下载hessian-3.1.6.jar导入项目，一起运行正常，测试完全通过。

原文出处：http://developer.51cto.com/art/201104/257498.htm