（二）Dubbo 分布式服务框架-快速入门

前言

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的常用方式有两种

• 注解方式（常用）
• XML方式（常用）
• 属性配置方式
• API配置方式

入门案例中我们就以注解方式进行讲解，后续会介绍XML方式的使用。

一、注册中心

Dubbo的注册中心可以使用很多种：

• Multicast 注册中心
• Zookeeper注册中心（官方推荐）
• Redis注册中心
• Simple注册中心

关于注册中心内容，可以后续详细介绍。在案例中我们使用Zookeeper注册中心的方式

1、Zookeeper 介绍

官方推荐使用 zookeeper 注册中心。注册中心负责服务地址的注册与查找，相当于目录服务，服务提供者和消费者只在启动时与注册中心交互，注册中心不转发请求，压力较小。
Zookeeper 是 Apache Hadoop 的子项目，是一个树型的目录服务，支持变更推送，适合作为Dubbox 服务的注册中心，工业强度较高，可用于生产环境。

2、Zookeeper 安装及启动

文章链接

二、代码编写

通用pom.xml文件(消费方端口需修改)

<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.tcy</groupId>
    <artifactId>dubbo-service</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <spring.version>4.2.4.RELEASE</spring.version>
    </properties>

    <dependencies>
        <!-- Spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-aspects</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jms</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <!-- dubbo相关 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.5.7</version>
        </dependency>
        <dependency>
            <groupId>org.apache.zookeeper</groupId>
            <artifactId>zookeeper</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>com.github.sgroschupf</groupId>
            <artifactId>zkclient</artifactId>
            <version>0.1</version>
        </dependency>

        <dependency>
            <groupId>javassist</groupId>
            <artifactId>javassist</artifactId>
            <version>3.11.0.GA</version>
        </dependency>

    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.3.2</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <configuration>
                    <!-- 指定端口 -->
                    <port>8080</port>
                    <!-- 请求路径 -->
                    <path>/</path>
                </configuration>
            </plugin>
        </plugins>
    </build>


</project>

1、服务提供方

• 创建服务方的接口及实现

package com.tcy.dubbo.service;

public interface HelloService {

    public String sayHello(String name);
}

package com.tcy.dubbo.service.impl;

import com.alibaba.dubbo.config.annotation.Service;
import com.tcy.dubbo.service.HelloService;

/**
 * 交给dubbo的service注解处理
 * @author tong
 *
 */
@Service
public class HelloServiceImpl implements HelloService {

    @Override
    public String sayHello(String name) {
        
        return "Hello"+name;
    }

}

• 创建服务器方配置文件(applicationContext-service.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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans    
                        http://www.springframework.org/schema/beans/spring-beans.xsd    
                        http://www.springframework.org/schema/context    
                        http://www.springframework.org/schema/context/spring-context.xsd    
                        http://code.alibabatech.com/schema/dubbo
                        http://code.alibabatech.com/schema/dubbo/dubbo.xsd
                        http://www.springframework.org/schema/mvc    
                        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- Dubbo的应用名称，通常使用项目名即可 -->
    <dubbo:application name="dubbo-service" />

    <!-- 配置Dubbo的注册中心地址 -->
    <dubbo:registry address="zookeeper://192.168.2.238:2181" />

    <!-- 配置Dubbo扫描类，将这个类作为服务进行发布 -->
    <dubbo:annotation package="com.tcy.dubbo.service.impl" />
    

</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"
    version="2.5">
    <display-name>dubbo-service</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>

    <!-- 加载Spring容器 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:applicationContext*.xml</param-value>
    </context-param>

    <!-- Spring监听器 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

</web-app>

2、服务消费方

• 创建消费方的Controller

package com.tcy.dubbo.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.alibaba.dubbo.config.annotation.Reference;
import com.tcy.dubbo.service.HelloService;

@RestController
@RequestMapping("/hello")
public class HelloController {
    
    @Reference
    private HelloService helloService;
    
    @RequestMapping("/test")
    public String hello(){
        return helloService.sayHello("Jack");
    }

}

需加入接口、无需实现类

• 创建消费放配置文件（springmvc.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:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/beans    
                        http://www.springframework.org/schema/beans/spring-beans.xsd    
                        http://www.springframework.org/schema/context    
                        http://www.springframework.org/schema/context/spring-context.xsd    
                        http://code.alibabatech.com/schema/dubbo
                        http://code.alibabatech.com/schema/dubbo/dubbo.xsd
                        http://www.springframework.org/schema/mvc    
                        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
                        
    <!-- 字符串转换器 -->                
    <mvc:annotation-driven>
        <mvc:message-converters register-defaults="true">
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <constructor-arg value="UTF-8" />
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>

    <!-- Dubbo的应用名称，通常使用项目名即可 -->
    <dubbo:application name="dubbo-consumer" />

    <!-- 配置Dubbo的注册中心地址 -->
    <dubbo:registry address="zookeeper://192.168.2.238:2181" />

    <!-- 配置Dubbo扫描类，将这个类作为服务进行发布 -->
    <dubbo:annotation package="com.tcy.dubbo.controller" />
    

</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"
    version="2.5">
    <display-name>dubbo-consumer</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>

    <!-- 编码过滤器 -->
    <filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CharacterEncodingFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    
    <servlet>
        <servlet-name>SpringMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springmvc.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>SpringMVC</servlet-name>
        <url-pattern>*.action</url-pattern>
    </servlet-mapping>

</web-app>

注：引入Dubbo标签无提示或报错：解决方案如下

• 下载dubbo.xsd文件

• eclipse配置
  Eclipse --- Window --- Preferences

  
  

注意：一定要记得手动写上/dubbo.xsd

三、启动服务测试