dubbo+zookeeper 分布式应用的快速入门

参考地址：https://blog.csdn.net/hua1586981/article/details/79195111
 互联网的快速迭代，随之而来的客户需求的不断变更，要求开发人员，具有敏捷的反应能力，快速应对需求变化。怎么快速应对变化，当然一个高可用，低耦合的分布式框架少不了，接下来，我介绍dubbo+zookeeper一个分布式框架。
DUBBO架构流程图：



dubbo:  是管理中间层的工具，在业务层到数据仓库间有非常多服务的接入和服务提供者需要调度，dubbo提供一个框架解决这个问题.
zookeeper: 用来注册服务和进行负载均衡，哪一个服务由哪一个机器来提供必需让调用者知道，简单来说就是ip地址和服务名称的对应关系。当然也可以通过硬编码的方式把这种对应关系在调用方业务代码中实现，但是如果提供服务的机器挂掉调用者无法知晓，如果不更改代码会继续请求挂掉的机器提供服务。zookeeper通过心跳机制可以检测挂掉的机器并将挂掉机器的ip和服务对应关系从列表中删除。至于支持高并发，简单来说就是横向扩展，在不更改代码的情况通过添加机器来提高运算能力。通过添加新的机器向zookeeper注册服务，服务的提供者多了能服务的客户就多了。
一，安装并启动zookeeper
zookeeper下载地址

把包下载后，解压到目录，例如：D:\software\work\zookeeper （解压后更名为zookeeper） 
复制zoo_sample.cfg 文件名(D:\software\work\zookeeper\conf) 为 zoo.cfg 
主要更改配置文件里面的日志目录，如下： 
dataDir=D:\zookeeper\data 
dataLogDir=D:\zookeeper\log启动 

进入到bin目录，并且启动zkServer.cmd。
二、创建maven工程
工程分为4个结构
dubbo 工程，主工程，主要导入公共jar包等
dubbo-api 工程，公共接口
dubbo-provider 工程，服务提供者
dubbo-consumer-user 和 dubbo-consumer 工程，服务消费者 


三、创建dubbo项目
    主要负责公共的jar包。
pom.xml文件如下：<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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion>
<groupId>dubbo</groupId>
<artifactId>dubbo</artifactId>
<packaging>pom</packaging>
<version>0.0.1-SNAPSHOT</version>
<!-- <modules>
<module>dubbo-api</module>
<module>dubbo-provider</module>
<module>dubbo-consumer</module>
<module>dubbo-consumer-user</module>
</modules>-->
<profiles>
<profile>
<modules>
<module>dubbo-api</module>
<module>dubbo-provider</module>
<module>dubbo-consumer</module>
<module>dubbo-consumer-user</module>
</modules>
</profile>
</profiles>

<name>dubbo Maven Webapp</name>
<url>http://maven.apache.org</url>

<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

<!-- spring版本号 -->
<spring.version>4.2.5.RELEASE</spring.version>

<!-- mybatis版本号 -->
<mybatis.version>3.2.8</mybatis.version>

<!-- mysql驱动版本号 -->
<mysql-driver.version>5.1.29</mysql-driver.version>

<!-- log4j日志包版本号 -->
<slf4j.version>1.7.18</slf4j.version>
<log4j.version>1.2.17</log4j.version>

</properties>
<dependencies>
<!-- <dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>-->
<!-- 添加jstl依赖 -->
<dependency>
<groupId>jstl</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>

<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>7.0</version>
</dependency>

<!-- 添加junit4依赖 -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<!-- 指定范围，在测试时才会加载 -->
<scope>test</scope>
</dependency>

<!-- 添加spring核心依赖 -->
<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>

4000
<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-context</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-aop</artifactId>
<version>${spring.version}</version>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
</dependency>

<!-- 添加mybatis依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>${mybatis.version}</version>
</dependency>

<!-- 添加mybatis/spring整合包依赖 -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis-spring</artifactId>
<version>1.2.2</version>
</dependency>

<!-- 添加mysql驱动依赖 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>${mysql-driver.version}</version>
</dependency>
<!-- 添加数据库连接池依赖 -->
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>1.2.2</version>
</dependency>

<!-- 添加fastjson -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.22</version>
</dependency>

<!-- 添加日志相关jar包 -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>${slf4j.version}</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>${slf4j.version}</version>
</dependency>

<!-- log end -->
<!-- 映入JSON -->
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.9.13</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.8.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.8.0</version>
</dependency>

<dependency>
<groupId>commons-fileupload</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.1</version>
</dependency>

<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>

<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.9</version>
</dependency>

<dependency>
<groupId>org.quartz-scheduler</groupId>
<artifactId>quartz</artifactId>
<version>2.2.1</version>
</dependency>

<dependency>
<groupId>org.apache.shiro</groupId>
<artifactId>shiro-core</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.apache.shiro</groupId>
<artifactId>shiro-web</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.apache.shiro</groupId>
<artifactId>shiro-spring</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.apache.shiro</groupId>
<artifactId>shiro-ehcache</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.apache.zookeeper</groupId>
<artifactId>zookeeper</artifactId>
<version>3.4.9</version>
</dependency>
<!-- dubbo -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>dubbo</artifactId>
<version>2.5.3</version>
<exclusions>
<exclusion>
<groupId>org.springframework</groupId>
<artifactId>spring</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.101tec</groupId>
<artifactId>zkclient</artifactId>
<version>0.10</version>
</dependency>

</dependencies>
<build>
<finalName>dubbo</finalName>
</build>
</project>四、dubbo-api项目
 封装公共的接口
新建DemoService and UserService
 DemoServicepublic interface DemoService {

List<String> getPermissions(Long id);
}UserServicepublic interface UserService {

String getName(String userId);
}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/maven-v4_0_0.xsd"> <parent>
<artifactId>dubbo</artifactId>
<groupId>dubbo</groupId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>dubbo-api</artifactId>
<packaging>war</packaging>
<name>dubbo-api Maven Webapp</name>
<url>http://maven.apache.org</url>
<build>
<finalName>dubbo-api</finalName>
</build>
</project>
五、dubbo-provider
实现项目dubbo-api的接口
DemoServiceImplpublic class DemoServiceImpl implements DemoService{

public List<String> getPermissions(Long id) {
List<String> demo = new ArrayList<String>();
demo.add(String.format("Permission_%d", id - 1));
demo.add(String.format("Permission_%d", id));
demo.add(String.format("Permission_%d", id + 1));
return demo;
}

}UserServiceImplpublic class UserServiceImpl implements UserService{

public String getName(String userId) {
return "Andy"+userId;
}
}applicationContext.xml文件<?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"> <!-- 定义了提供方应用信息，用于计算依赖关系。在dubbo-admin 或 dubbo-monitor 会显示这个名字，方便识别 -->
<dubbo:application name="admin-provider" owner="admin" organization="dubbox"/>
<!-- 使用zookeeper 注册中心暴露服务，注意要先开启 zookeeper -->
<dubbo:registry address="zookeeper://localhost:2181"/>
<!-- 用dubbo协议在20880端口暴露服务 -->
<dubbo:protocol name="dubbo" port="20880"/>
<!-- 用dubbo 协议实现定义好的 api 接口 -->
<dubbo:service interface="com.dubbo.service.DemoService" ref="demoService" protocol="dubbo"/>
<dubbo:service interface="com.dubbo.service.UserService" ref="userService" protocol="dubbo"/>
<!-- 具体实现接口的bean -->
<bean id="demoService" class="com.dubbo.service.impl.DemoServiceImpl"/>
<bean id="userService" class="com.dubbo.service.impl.UserServiceImpl"/>

</beans>pom.xml<?xml version="1.0" encoding="UTF-8"?>
<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"> <parent>
<artifactId>dubbo</artifactId>
<groupId>dubbo</groupId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>dubbo-provider</artifactId>

<dependencies>
<dependency>
<groupId>dubbo</groupId>
<artifactId>dubbo-api</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>dubbo</groupId>
<artifactId>dubbo-api</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
</dependencies>
</project>test中启动服务package test;

import java.io.IOException;

import org.springframework.context.support.ClassPathXmlApplicationContext;

/**
* 启动服务
*/
public class Start {
public static void main(String[] args) throws IOException {
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
System.out.println(context.getDisplayName() + ":here");
context.start();
System.out.println("provider start");
System.in.read();
}
}

六、dubbo-consumer-user
服务消费者
注入dubbo-api的jar文件，注入userServiceBean
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: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"> <!-- 定义了提供方应用信息，用于计算依赖关系。在dubbo-admin 或 dubbo-monitor 会显示这个名字，方便识别 -->
<dubbo:application name="user-consumer" owner="user" organization="dubbox"/>
<!-- 向zookeeper 订阅provider 的地址，由zookeeper 定时推送 -->
<dubbo:registry address="zookeeper://localhost:2181"/>
<!-- 使用dubbo 协议调用定义好的 api 接口 -->
<dubbo:reference id="userService" interface="com.dubbo.service.UserService"/>

</beans>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/maven-v4_0_0.xsd"> <parent>
<artifactId>dubbo</artifactId>
<groupId>dubbo</groupId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>dubbo-consumer-user</artifactId>

<dependencies>
<dependency>
<groupId>dubbo</groupId>
<artifactId>dubbo-api</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>dubbo</groupId>
<artifactId>dubbo-api</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
</dependencies>
</project>
test中启动类
/**
* 消费者调用
*/
public class Start {
public static void main(String[] args) {
//测试常规服务
ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
context.start();
System.out.println("consumer user start");
UserService userService = context.getBean(UserService.class);
System.out.println("consumer user");
System.out.println(userService.getName("1"));
}
}启动顺序：先启动zookeeper --> provider --> cousumer
这样一套简易的分布是应用就构建好了，接下来介绍一个dubbo图形化桌面工具
dubbo-admin的下载，可自行到官网下载：https://github.com/alibaba/dubbo 下载后把war包放入tomcat的webapps的root目录下，启动tomcat浏览器输入：http://localhost:8080/dubbo-admin/ 

默认账号： root 密码：root



war的获取：
打开dubbo-admin，打开终端，执行 mvn packer -Dmaven.test.skip =true // mvn -install -Dmaven.test.skip=true