Spring RPC 介绍（Burlap）

Spring为各种远程访问技术的集成提供了工具类。Spring远程支持是由普通（Spring）POJO实现的，这使得开发具有远程访问功能的服务变得相当容易。目前，Spring支持四种远程技术：
1.远程方法调用（RMI）。通过使用 RmiProxyFactoryBean 和 RmiServiceExporter，Spring同时支持传统的RMI（使用 java.rmi.Remote接口和java.rmi.RemoteException）和通过RMI调用器实现的透明远程调用（支持任何Java接口）。
2.Spring的HTTP调用器。Spring提供了一种特殊的允许通过HTTP进行Java串行化的远程调用策略，支持任意Java接口（就像RMI调用器）。相对应的支持类是 HttpInvokerProxyFactoryBean和 HttpInvokerServiceExporter。
3.Hessian。通过 HessianProxyFactoryBean 和 HessianServiceExporter，可以使用Caucho提供的基于HTTP的轻量级二进制协议来透明地暴露服务。
4.Burlap。 Burlap是Caucho的另外一个子项目，可以作为Hessian基于XML的替代方案。Spring提供了诸如 BurlapProxyFactoryBean 和 BurlapServiceExporter 的支持类。
5.JAX RPC。Spring通过JAX-RPC为远程Web服务提供支持，以Web Services的形式发布。常见开源的项目有Axis，CXF，Xfire等

6.JMS（待实现）。

上一节介绍了HttpInvoker的使用，Burlap、RIM和Hessian的使用与其类似。下面以Burlap为例测试。

 Burlap是一个轻量级的XML RPC协议，这使得他可以移植到任何可以解析XML的语言中。比起Hessian，它的可读性更强。和其他基于Xml的远程技术（如SOAP和XML-RPC）不同，它的消息结构尽可能简单，不需要额外的外部定义语言(如WSDL或IDL)。Hessian,Burlap是Caucho提供的两种基于Http的轻量级远程服务， Burlap现在已经集成到hessian.jar中，不作为一个单独的项目了。

代码示例如下：

1.添加依赖jar包

<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>4.0.9.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-expression</artifactId>
			<version>4.0.9.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>4.0.9.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>4.0.9.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-tx</artifactId>
			<version>4.0.9.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>com.caucho</groupId>
			<artifactId>hessian</artifactId>
			<version>4.0.38</version>
		</dependency>

2.接口、实现类

对象User.java

package cn.slimsmart.burlap.spring.demo;

import java.io.Serializable;

public class User implements Serializable{
	private static final long serialVersionUID = 1L;
	
	private String name;
	private int age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	@Override
	public String toString() {
		return "name="+name+",age="+age;
	}
}

接口：UserService.java

package cn.slimsmart.burlap.spring.demo;

public interface UserService {
	User getUser(String name);
}

实现类：UserServiceImpl.java

package cn.slimsmart.burlap.spring.demo;

public class UserServiceImpl implements UserService{

	@Override
	public User getUser(String name) {
		User user = new User();
		user.setAge(30);
		user.setName(name);
		return user;
	}
}

3.服务端配置

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
				http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
				http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd"
	default-lazy-init="true">
	
    <bean  id="userServiceImpl" class="cn.slimsmart.burlap.spring.demo.UserServiceImpl"/>
</beans>

applicationContext-burlap-exporter.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
				http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
				http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd"
	default-lazy-init="true">
	
     <bean name="/userService" class="org.springframework.remoting.caucho.BurlapServiceExporter">
        <property name="service" ref="userServiceImpl" />
        <property name="serviceInterface" value="cn.slimsmart.burlap.spring.demo.UserService"/>
    </bean>
    
</beans>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">
	<display-name>ThriftTest</display-name>

	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>
			classpath:applicationContext.xml
		</param-value>
	</context-param>
	
	<servlet>
		<servlet-name>dispatcherServlet</servlet-name>
		<servlet-class>
			org.springframework.web.servlet.DispatcherServlet
		</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath*:/applicationContext-burlap-exporter.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>
	
	<servlet-mapping>
		<servlet-name>dispatcherServlet</servlet-name>
		<url-pattern>/remote/*</url-pattern>
	</servlet-mapping>
	
	<listener>
		<listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
	</listener>
 
	<session-config>
		<session-timeout>30</session-timeout>
	</session-config>
	
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
	</welcome-file-list>
	
</web-app>

4.客户端配置

applicationContext-burlap.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
				http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
				http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
				http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd"
	default-lazy-init="true">

	<bean id="userService"
		class="org.springframework.remoting.caucho.BurlapProxyFactoryBean">
		<property name="serviceUrl"
			value="http://127.0.0.1:8080/burlap-spring-demo/remote/userService" />
		<property name="serviceInterface" value="cn.slimsmart.burlap.spring.demo.UserService" />
	</bean>
</beans>

5.测试运行类

UserServiceClientTest.java

package cn.slimsmart.burlap.spring.demo;

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

public class UserServiceClientTest {
	@SuppressWarnings("resource")
	public static void main(String[] args) {
		ApplicationContext context = new ClassPathXmlApplicationContext("classpath:applicationContext-burlap.xml");
		UserService client = context.getBean(UserService.class);
		System.out.println(client.getUser("lucy"));
	}
}

通过http请求抓包可以看见协议定义

请求：

<burlap:call>
	<method>getUser</method>
	<string>lucy</string>
</burlap:call>

相应：

<burlap:reply>
	<map>
		<type>cn.slimsmart.burlap.spring.demo.User</type>
		<string>name</string>
		<string>lucy</string>
		<string>age</string>
		<int>30</int>
	</map>
</burlap:reply>

代码：http://download.csdn.net/detail/tianwei7518/8468333