====== dubbo项目示例 ======
===== 介绍 =====
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。

官网：[[http://dubbo.io/Home-zh.htm|dubbo.io]]

其核心部分包含:

  * 远程通讯: 提供对多种基于长连接的NIO框架抽象封装，包括多种线程模型，序列化，以及“请求-响应”模式的信息交换方式。
  * 集群容错: 提供基于接口方法的透明远程过程调用，包括多协议支持，以及软负载均衡，失败容错，地址路由，动态配置等集群支持。
  * 自动发现: 基于注册中心目录服务，使服务消费方能动态的查找服务提供方，使地址透明，使服务提供方可以平滑增加或减少机器。

Dubbo能做什么？

  * 透明化的远程方法调用，就像调用本地方法一样调用远程方法，只需简单配置，没有任何API侵入。
  * 软负载均衡及容错机制，可在内网替代F5等硬件负载均衡器，降低成本，减少单点。
  * 服务自动注册与发现，不再需要写死服务提供方地址，注册中心基于接口名查询服务提供者的IP地址，并且能够平滑添加或删除服务提供者。
===== 示例项目 =====
使用zookeeper作为注册中心，server项目注册服务UserService，client项目消费服务UserService
===== server项目 =====
注意：server-service模块必须deploy到nexus上，让消费项目依赖
==== pom.xml ====
<code xml pom.xml>
			<!-- dubbo -->
			<dependency>
				<groupId>com.alibaba</groupId>
				<artifactId>dubbo</artifactId>
				<version>2.5.3</version>
				<exclusions>
					<exclusion>
						<artifactId>spring</artifactId>
						<groupId>org.springframework</groupId>
					</exclusion>
					<exclusion>
						<artifactId>commons-logging</artifactId>
						<groupId>commons-logging</groupId>
					</exclusion>
					<exclusion>
						<artifactId>log4j</artifactId>
						<groupId>log4j</groupId>
					</exclusion>
				</exclusions>
			</dependency>

			<!-- zkclient -->
			<dependency>
				<groupId>com.github.sgroschupf</groupId>
				<artifactId>zkclient</artifactId>
				<version>0.1</version>
				<exclusions>
					<exclusion>
						<artifactId>junit</artifactId>
						<groupId>junit</groupId>
					</exclusion>
					<exclusion>
						<artifactId>log4j</artifactId>
						<groupId>log4j</groupId>
					</exclusion>
				</exclusions>
			</dependency>
</code>
==== application-provider.xml ====
<code xml application-provider.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:dubbo="http://code.alibabatech.com/schema/dubbo"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://code.alibabatech.com/schema/dubbo
        http://code.alibabatech.com/schema/dubbo/dubbo.xsd
        ">

	<!-- dubbo应用名称 -->
	<dubbo:application name="server" />
	
	<!-- dubbo注册地址 -->
	<dubbo:registry address="zookeeper://121.40.171.96:2181" />

	<!-- dubbo注册端口 -->
	<dubbo:protocol name="dubbo" port="-1" />

	<!-- 监听注册 -->
	<dubbo:monitor protocol="registry" />

	<!-- dubbo对外开放接口 -->
	<dubbo:service interface="com.gxx.dubbo.server.service.UserService"
		ref="userService" version="1.0.0" retries="0" timeout="10000" />

</beans>
</code>
==== UserService.java ====
<code java UserService.java>
package com.gxx.dubbo.server.service;

import com.gxx.dubbo.server.model.vo.User;

/**
 * 用户服务接口
 * @author Gxx
 */
public interface UserService {
	/**
	 * 根据id查询用户
	 * @return
	 */
	public User selectUserById(int id);
}
</code>
==== UserServiceImpl.java ====
<code java UserServiceImpl.java>
package com.gxx.dubbo.server.biz.impl;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import com.gxx.dubbo.server.dao.UserMapper;
import com.gxx.dubbo.server.model.vo.User;
import com.gxx.dubbo.server.service.UserService;

/**
 * 用户服务接口实现类
 * @author Gxx
 */
@Service("userService")
public class UserServiceImpl implements UserService {
	
	/**
	 * 日志处理器
	 */
	Logger logger = Logger.getLogger(UserServiceImpl.class);

	/**
	 * 用户实体操作类
	 */
	@Autowired
	private UserMapper userMapper;

	/**
	 * 根据id查询用户
	 * @return
	 */
	@Override
	@Transactional(readOnly = true, propagation = Propagation.REQUIRED)
	public User selectUserById(int id) {
		return userMapper.selectByPrimaryKey(id);
	}
}
</code>
===== client项目 =====
注意：client需要依赖server-service模块
==== pom.xml ====
<code xml pom.xml>
			<!-- dubbo -->
			<dependency>
				<groupId>com.alibaba</groupId>
				<artifactId>dubbo</artifactId>
				<version>2.5.3</version>
				<exclusions>
					<exclusion>
						<artifactId>spring</artifactId>
						<groupId>org.springframework</groupId>
					</exclusion>
					<exclusion>
						<artifactId>commons-logging</artifactId>
						<groupId>commons-logging</groupId>
					</exclusion>
					<exclusion>
						<artifactId>log4j</artifactId>
						<groupId>log4j</groupId>
					</exclusion>
				</exclusions>
			</dependency>

			<!-- zkclient -->
			<dependency>
				<groupId>com.github.sgroschupf</groupId>
				<artifactId>zkclient</artifactId>
				<version>0.1</version>
				<exclusions>
					<exclusion>
						<artifactId>junit</artifactId>
						<groupId>junit</groupId>
					</exclusion>
					<exclusion>
						<artifactId>log4j</artifactId>
						<groupId>log4j</groupId>
					</exclusion>
				</exclusions>
			</dependency>
			<!-- 依赖其他模块开始 -->
			<dependency>
				<groupId>com.gxx.dubbo</groupId>
				<artifactId>server-service</artifactId>
				<version>0.0.1-SNAPSHOT</version>
			</dependency>
			<!-- 依赖其他模块结束 -->
</code>
==== application-consumer.xml ====
<code xml application-consumer.xml>
<?xml version="1.0" encoding="UTF-8"?>
<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-4.1.xsd
	http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.1.xsd
	http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.1.xsd
	http://code.alibabatech.com/schema/dubbo        http://code.alibabatech.com/schema/dubbo/dubbo.xsd"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns="http://www.springframework.org/schema/beans"
	xmlns:dubbo="http://code.alibabatech.com/schema/dubbo">

	<!-- dubbo应用名称 -->
	<dubbo:application name="client" />
	
	<!-- dubbo注册地址 -->
	<dubbo:registry address="zookeeper://121.40.171.96:2181" />

	<!-- 消费接口类开始 -->
	<dubbo:reference id="userService" cluster="failfast"
		interface="com.gxx.dubbo.server.service.UserService"
		lazy="true" check="false" version="1.0.0" timeout="10000" />
	<!-- 消费接口类结束 -->

</beans>
</code>
==== RemoteService.java ====
<code java RemoteService.java>
package com.gxx.dubbo.client.remote.service;

import com.gxx.dubbo.server.model.vo.User;

/**
 * 远程服务接口
 * @author Gxx
 */
public interface RemoteService {
	/**
	 * 根据id查询用户
	 * @return
	 */
	public User selectUserById(int id);
}
</code>
==== RemoteServiceImpl.java ====
<code java RemoteServiceImpl.java>
package com.gxx.dubbo.client.remote.impl;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.gxx.dubbo.client.remote.service.RemoteService;
import com.gxx.dubbo.server.model.vo.User;
import com.gxx.dubbo.server.service.UserService;

/** 
 * 远程服务接口实现类
 * @author Gxx
 */
@Service("remoteService")
public class RemoteServiceImpl implements RemoteService {
	/**
	 * 日志记录器
	 */
	Logger logger = Logger.getLogger(RemoteServiceImpl.class);

	/**
	 * 用户服务接口
	 */
	@Autowired
	private UserService userService;
	
	/**
	 * 根据id查询用户
	 * @return
	 */
	public User selectUserById(int id) {
		return userService.selectUserById(id);
	}
}
</code>
==== RemoteController.java ====
<code java RemoteController.java>
package com.gxx.dubbo.client.web;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.gxx.dubbo.client.remote.service.RemoteService;
import com.gxx.dubbo.server.model.vo.User;

/**
 * 远程控制类
 * @author Gxx
 */
@Controller
@RequestMapping("/remote/")
public class RemoteController {

	/**
	 * 日志处理器
	 */
	private final Logger logger = Logger.getLogger(RemoteController.class);
	
	@Autowired
	private RemoteService remoteService;
	
	/**
	 * 远程查询用户
	 * @return
	 */
	@RequestMapping(value = "/get")
	public @ResponseBody String get(HttpServletRequest request) {
		logger.info("远程查询用户开始~");
		User user = remoteService.selectUserById(Integer.parseInt(request.getParameter("id")));
		logger.info("远程查询用户结束~");
		return user == null ? "查询不到用户！" : user.toString();
	}
}
</code>
===== 部署测试 =====
把server-web和client-web都部署到tomcat下，访问
<code>http://localhost:9090/client-web/remote/get.htm?id=9</code>
得到
<code>User [id=9, name=lqy, password=123qwe, createDate=20150618, createTime=000000]</code>
可以看到日志client.log
<code>
2017-05-30 11:18:49,384 INFO  远程查询用户开始~
2017-05-30 11:18:50,420 INFO  远程查询用户结束~
</code>
日志server.log
<code>
2017-05-30 11:18:50,005 INFO  接收到消费者请求，根据ID=[9]查询用户!
</code>
===== zkui =====
server-web和client-web都部署之后，在zookeeper管理界面zkui上可以看到，consumer和provider的信息
{{:分享:技术:dubbo:1.jpeg?800|}}
===== dubbo-admin =====
server-web和client-web都部署之后，在zookeeper管理界面dubbo-admin上可以看到，consumer和provider的信息
{{:分享:技术:dubbo:3.jpeg?800|}}

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===== 附源码 =====
{{:分享:技术:dubbo:server.zip|}}

{{:分享:技术:dubbo:client.zip|}}
===== 生成archetype原型 =====
生成archetype，以后有相关项目可以根据原型生成，速度比较快。

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