Hessian实现远程调用服务的小例子
Hessian是一个轻量级的remoting on http工具，使用简单的方法提供了RMI（Remote Method Invocation，远程方法调用）的功能。采用的是二进制RPC（Remote Procedure Call Protocol，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
场景1：服务端 客户端都不使用spring
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web project。将hessian-3.2.0.jar放入WEB-INF/lib文件夹中。
创建接口
package com.mooing.hessian;
public interface DemoApi {
public void setName(String name);
public String sayHello();
public User getUser();
}
实现接口
package com.mooing.hessian;
public class DemoService implements DemoApi{
private String name;
@Override
public void setName(String name) {
this.name=name;
}
@Override
public String sayHello() {
System.out.println("hello,world!");
return "hello:"+name;
}
@Override
public User getUser() {
return new User("ming","m123");
}
}
创建User，注意实现序列化
package com.mooing.hessian;
import java.io.Serializable;
public class User implements Serializable {
private static final long serialVersionUID = 1L;
private String name = "kitty";
private String psw = "nopww";
public User() {
}
public User(String name, String psw) {
super();
this.name = name;
this.psw = psw;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPsw() {
return psw;
}
public void setPsw(String psw) {
this.psw = psw;
}
}
配置web.xml
<servlet>
<servlet-name>hessian</servlet-name>
<servlet-class>com.caucho.hessian.server.HessianServlet</servlet-class>
<init-param>
<param-name>service-class</param-name>
<param-value>com.mooing.hessian.DemoService</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>hessian</servlet-name>
<url-pattern>/helloworld</url-pattern>
</servlet-mapping>
客户端代码
注意如果新建客户端工程，需引入上述jar，还需要服务端导出DemoService和User两个类的jar，放入lib。或创建两个一摸一样的类。
package com.mooing.hessian;
import java.NET.MalformedURLException;
import com.caucho.hessian.client.HessianProxyFactory;
public class HessianClient {
public static void main(String[] args) throws MalformedURLException, ClassNotFoundException {
String url = "http://localhost:8080/HessianServer/helloworld";
HessianProxyFactory pf = new HessianProxyFactory();
DemoApi da = (DemoApi) pf.create(DemoApi.class, url);
da.setName("test");
System.out.println(da.sayHello());
System.out.println(da.getUser());
}
}
tomcat启动服务端，运行客户端，结果如下
hello:test
ming
m123
场景2：服务端 客户端都使用spring（在上述基础上）
依赖的包：
pom.xml
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.lzt</groupId>
<artifactId>maven_server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>maven_server</name>
<url>http://maven.apache.org</url>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<!-- spring版本号 -->
<spring.version>4.0.2.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.caucho</groupId>
<artifactId>hessian</artifactId>
<version>4.0.38</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
<!-- spring核心包 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-oxm</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>
</dependencies>
</project>
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>
</servlet>
<servlet-mapping>
<servlet-name>remote</servlet-name>
<url-pattern>/remote/*</url-pattern>
</servlet-mapping>
以下是remote-servlet.xml的内容：
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<!-- 注入内部实现接口 -->
<bean id="demoService" class="com.mooing.hessian.DemoService" />
<!-- 注入hessian发布接口 name为调用名称-->
<bean name="/helloDemo" class="org.springframework.remoting.caucho.HessianServiceExporter">
<!-- 关联接口实现 -->
<property name="service" ref="demoService" />
<!-- 关联接口 -->
<property name="serviceInterface" value="com.mooing.hessian.DemoApi" />
</bean>
</beans>
1) 如果客户端不使用spring，客户端代码如下
import java.Net.MalformedURLException;
import com.caucho.hessian.client.HessianProxyFactory;
import com.mooing.hessian.DemoApi;
public class ClientSpring {
public static void main(String[] args) throws MalformedURLException, ClassNotFoundException {
String url = "http://localhost:8080/项目名/remote/helloDemo";
HessianProxyFactory pf = new HessianProxyFactory();
DemoApi da = (DemoApi) pf.create(url);
da.setName("test");
System.out.println(da.sayHello());
System.out.println(da.getUser());
}
}
2) 如果客户端使用spring,需要导入上述jar，在客户端工程src目录下，新建一个remote-hessian.xml，这个文件可随意命名，内容为：
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
<bean id="helloDemo" class="org.springframework.remoting.caucho.HessianProxyFactoryBean">
<property name="serviceUrl">
<value>
http://localhost:8080/服务端项目名/remote/helloDemo
</value>
</property>
<property name="serviceInterface">
<value>com.mooing.hessian.DemoApi</value>
</property>
</bean>
</beans>
客户端代码
import java.net.MalformedURLException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.caucho.hessian.client.HessianProxyFactory;
import com.mooing.hessian.DemoApi;
public class ClientSpring {
public static void main(String[] args) throws MalformedURLException, ClassNotFoundException {
// String url = "http://localhost:8080/jms1/remote/helloDemo";
// HessianProxyFactory pf = new HessianProxyFactory();
// DemoApi da = (DemoApi) pf.create(url);
// da.setName("test");
// System.out.println(da.sayHello());
// System.out.println(da.getUser());
ApplicationContext context = new ClassPathXmlApplicationContext("remote-hessian.xml");
DemoApi da = (DemoApi) context.getBean("helloDemo");
da.setName("test spring");
System.out.println(da.sayHello());
System.out.println(da.getUser());
}
}
本文转载于：http://blog.csdn.net/chiperfect/article/details/6636807
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