1. 概述Dubbo是一个分布式服务框架,致力于提供高性能和透明化的RPC远程服务调用方案,以及SOA服务治理方案。主要核心部件Remoting: 网络通信框架,实现了sync-over-async 和 request-response 消息机制.RPC: 一个远程过程调用的抽象,支持负载均衡、容灾和集群功能Registry: 服务目录框架用于服务的注册和服务事件发布和订阅。Dubbo采用全Spring配置方式,透明化接入应用,对应用没有任何API侵入,只需用Spring加载Dubbo的配置即可,Dubbo基于Spring的Schema扩展进行加载。dubbo架构图如下所示:
节点角色说明:
Provider: 暴露服务的服务提供方。
Consumer: 调用远程服务的服务消费方。
Registry: 服务注册与发现的注册中心。
Monitor: 统计服务的调用次调和调用时间的监控中心。
Container: 服务运行容器。
调用关系说明:
0 服务容器负责启动,加载,运行服务提供者。
1. 服务提供者在启动时,向注册中心注册自己提供的服务。
2. 服务消费者在启动时,向注册中心订阅自己所需的服务。
3. 注册中心返回服务提供者地址列表给消费者,如果有变更,注册中心将基于长连接推送变更数据给消费者。
4. 服务消费者,从提供者地址列表中,基于软负载均衡算法,选一台提供者进行调用,如果调用失败,再选另一台调用。
5. 服务消费者和提供者,在内存中累计调用次数和调用时间,定时每分钟发送一次统计数据到监控中心。
2. 实例
2.1 pom.xml首先maven项目增加dubbo的jar依赖,因为要用到zookeeper注册中心,也要依赖但是要去掉自带的log4j。
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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<groupId>test</groupId>
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<artifactId>test</artifactId>
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<version>1.0-SNAPSHOT</version>
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<packaging>jar</packaging>
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<properties>
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<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
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<spring.version>3.1.4.RELEASE</spring.version>
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<slf4j.version>1.6.6</slf4j.version>
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</properties>
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<dependencies>
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<!-- dubbo -->
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<dependency>
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<groupId>com.alibaba</groupId>
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<artifactId>dubbo</artifactId>
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<version>2.5.3</version>
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</dependency>
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<!-- zookeeper -->
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<dependency>
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<groupId>org.apache.zookeeper</groupId>
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<artifactId>zookeeper</artifactId>
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<version>3.4.6</version>
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<exclusions>
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<exclusion>
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<groupId>log4j</groupId>
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<artifactId>log4j</artifactId>
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</exclusion>
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</exclusions>
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</dependency>
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<!-- Spring -->
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-aop</artifactId>
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<version>${spring.version}</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-asm</artifactId>
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<version>${spring.version}</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-core</artifactId>
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<version>${spring.version}</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-beans</artifactId>
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<version>${spring.version}</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-context</artifactId>
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<version>${spring.version}</version>
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</dependency>
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<dependency>
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<groupId>org.springframework</groupId>
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<artifactId>spring-expression</artifactId>
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<version>${spring.version}</version>
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</dependency>
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<!-- log -->
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<dependency>
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<groupId>log4j</groupId>
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<artifactId>log4j</artifactId>
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<version>1.2.16</version>
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</dependency>
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</dependencies>
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</project>
因为要增加zookeeper的注册管理,所以如果有可用的zookeeper就用可用的zookeeper。本实例使用的zk地址是192.168.4.114:2181
2.2
dubbo-provider.xml
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<?xml version="1.0" encoding="UTF-8"?>
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<beans xmlns="http://www.springframework.org/schema/beans"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
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xsi:schemaLocation="http://www.springframework.org/schema/beans
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http://www.springframework.org/schema/beans/spring-beans.xsd
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http://code.alibabatech.com/schema/dubbo
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http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
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<!-- 提供方应用信息,用于计算依赖关系 -->
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<dubbo:application name = "hello-world-app-provider" />
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<!--zookeeper注册中心 -->
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<dubbo:registry protocol="zookeeper" address="192.168.4.114:2181" />
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<!-- 用dubbo协议在20880端口暴露服务 -->
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<dubbo:protocol name="dubbo" port="20880" />
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<!-- 声明需要暴露的服务接口 -->
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<dubbo:service interface="com.mt.test.DemoService" ref="demoProvideService"/>
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<!-- 具体的实现bean -->
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<bean id="demoProvideService" class="com.mt.test.DemoServiceImpl" />
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</beans>
2.3 dubbo-consumer.xml
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<?xml version="1.0" encoding="UTF-8"?>
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<beans xmlns="http://www.springframework.org/schema/beans"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xmlns:dubbo="http://code.alibabatech.com/schema/dubbo"
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xsi:schemaLocation="http://www.springframework.org/schema/beans
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http://www.springframework.org/schema/beans/spring-beans.xsd
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http://code.alibabatech.com/schema/dubbo
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http://code.alibabatech.com/schema/dubbo/dubbo.xsd">
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<!-- 消费方应用名,用于计算依赖关系,不是匹配条件,不要与提供方一样 -->
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<dubbo:application name="hello-world-app-consumer"/>
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<!-- 使用zookeeper注册中心暴露服务地址 -->
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<dubbo:registry protocol="zookeeper" address="192.168.4.114:2181"/>
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<!-- 生成远程服务代理,可以和本地bean一样使用demoService -->
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<dubbo:reference id="demoConsumeService" interface="com.mt.test.DemoService"/>
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</beans>
2.4 DemoService.java
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package com.mt.test;
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import java.util.List;
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public interface DemoService {
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public String sayHello(String name);
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public List getUsers();
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}
2.5 DemoServiceImpl.java
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package com.mt.test;
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import java.util.ArrayList;
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import java.util.List;
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public class DemoServiceImpl implements DemoService{
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@Override
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public String sayHello(String name) {
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return "Hello " + name;
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}
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@Override
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public List getUsers() {
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List list = new ArrayList();
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User u1 = new User();
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u1.setName("jack");
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u1.setAge(20);
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u1.setSex("男");
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User u2 = new User();
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u2.setName("tom");
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u2.setAge(21);
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u2.setSex("女");
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User u3 = new User();
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u3.setName("rose");
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u3.setAge(19);
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u3.setSex("女");
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list.add(u1);
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list.add(u2);
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list.add(u3);
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return list;
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}
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}
2.6 LuncherProvider.java
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package com.mt.test;
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import org.springframework.context.support.ClassPathXmlApplicationContext;
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import org.springframework.context.ApplicationContext;
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public class LuncherProvider {
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public static void main(String[] args) throws Exception {
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LuncherProvider luncher = new LuncherProvider();
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luncher.start();
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System.in.read(); // 为保证服务一直开着,利用输入流的阻塞来模拟
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}
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public void start() {
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String configLocation = "spring/dubbo-provider.xml";
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ApplicationContext context = new ClassPathXmlApplicationContext(configLocation);
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String[] names = context.getBeanDefinitionNames();
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System.out.print("Beans:");
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for (String string : names)
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System.out.print(string + ",");
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System.out.println();
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}
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}
2.7 LuncherConsumer.java
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package com.mt.test;
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import org.springframework.context.ApplicationContext;
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import org.springframework.context.support.ClassPathXmlApplicationContext;
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public class LuncherConsumer {
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public static void main(String[] args) throws Exception {
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LuncherConsumer luncher = new LuncherConsumer();
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luncher.start();
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}
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void start() {
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String configLocation = "spring/dubbo-consumer.xml";
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ApplicationContext context = new ClassPathXmlApplicationContext(configLocation);
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String[] names = context.getBeanDefinitionNames();
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System.out.print("Beans:");
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for (String string : names) {
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System.out.print(string);
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System.out.print(",");
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}
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System.out.println();
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DemoService ds = (DemoService) context.getBean("demoConsumeService");
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System.out.println(ds.sayHello("hehe"));
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System.out.println(ds.getUsers());
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}
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}
2.8 User.Java
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package com.mt.test;
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import java.io.Serializable;
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//必须实现Serializable接口
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public class User implements Serializable {
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private static final long serialVersionUID = -2814022769568306965L;
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private String name;
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private Integer age;
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private String sex;
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public Integer getAge() {
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return age;
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}
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public void setAge(Integer age) {
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this.age = age;
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}
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public String getSex() {
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return sex;
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}
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public void setSex(String sex) {
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this.sex = sex;
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}
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@Override
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public String toString() {
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return "User{" +
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"name='" + name + '\'' +
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", age=" + age +
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", sex='" + sex + '\'' +
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'}';
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}
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}<strong>
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</strong>
运行结果:
(1)provider:
Beans:hello-world-app-provider,com.alibaba.dubbo.config.RegistryConfig,dubbo,com.mt.test.DemoService,demoProvideService,
(2)consumer:
Beans:hello-world-app-consumer,com.alibaba.dubbo.config.RegistryConfig,demoConsumeService,
Hello hehe
[User{name='jack', age=20, sex='男'}, User{name='tom', age=21, sex='女'}, User{name='rose', age=19, sex='女'}]