Java工程师 Apache Dubbo 3 🌱第一个入门案例

🎄Apache Dubbo第一个入门案例

🍭整体概述

第一个入门案例将创建一个Maven项目父项目中包含4个模块依次为：

（1）dubbo-pojo模块，负责提供公用的实体类

（2）dubbo-interface模块，负责提供项目中需要使用到的接口依赖dubbo-pojo模块

（3）dubbo-service模块，负责提供后端服务依赖dubbo-interface模块

（4）dubbo-web模块，运行web应用

🍭dubbo-pojo模块

模块当中只有一个User实体类

public class User implements Serializable {
    private int id;
    private String username;
    private String password;
    ...
}

dubbo-pojo模块使用之前必须先用Maven命令进行install或者直接点击界面提供的install按钮

🍭dubbo-interface模块

interface模块定义项目中要使用的接口

public interface UserService {
    /**
     * 测试接口1
     */
    String helloWorld();
    /**
     * 测试接口2 查询用户
     */
    User findUserById(int id);
}

dubbo-interface需要引入的依赖如下（只需要引入dubbo-pojo模块）

<dependencies>
    <dependency>
        <groupId>com.bigbigmeng</groupId>
        <artifactId>dubbo-pojo</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
</dependencies>

🍭dubbo-service模块

🌴配置依赖

dubbo-service模块是真正提供远程可调用服务的模块它需要引入的依赖如下

<dependencies>
    <!-- servlet3.0规范的坐标 -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope>
    </dependency>
    <!--spring的坐标-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <!--springmvc的坐标-->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring.version}</version>
    </dependency>

    <!--日志-->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-api</artifactId>
        <version>1.7.21</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.21</version>
    </dependency>

    <!-- Dubbo的起步依赖 版本2.7之后统一为 org.apache.dubbo -->
    <dependency>
        <groupId>org.apache.dubbo</groupId>
        <artifactId>dubbo</artifactId>
        <version>${dubbo.version}</version>
    </dependency>
    <!-- ZooKeeper客户端实现 -->
    <dependency>
        <groupId>org.apache.curator</groupId>
        <artifactId>curator-framework</artifactId>
        <version>${zookeeper.version}</version>
    </dependency>
    <!--ZooKeeper客户端实现 -->
    <dependency>
        <groupId>org.apache.curator</groupId>
        <artifactId>curator-recipes</artifactId>
        <version>${zookeeper.version}</version>
    </dependency>

    <!--依赖公共的接口模块 -> dubbo-interface -> dubbo-pojo -->
    <dependency>
        <groupId>com.bigbigmeng</groupId>
        <artifactId>dubbo-interface</artifactId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <!-- tomcat插件 启动远程接口的服务 -->
        <plugin>
            <groupId>org.apache.tomcat.maven</groupId>
            <artifactId>tomcat7-maven-plugin</artifactId>
            <version>2.1</version>
            <configuration>
                <port>9000</port>
                <path>/</path>
            </configuration>
        </plugin>
    </plugins>
</build>

根据pom.xml中配置的Tomcat插件的配置 9000端口 service模块启动在9000端口

🌴提供的服务

主要提供的service服务 -> 一个UserServiceImpl类实现了dubbo-interface模块提供的UserService接口

@Service // 将这个类提供的方法（服务）对外发布 将访问的地址 ip 端口 路径 注册到注册中心中
public class UserServiceImpl implements UserService {

    public String helloWorld() {
        return "hello BigBigMeng~ Welcome to use Dubbo!";
    }

    public User findUserById(int id) {
        //查询User对象
        User user = new User(1,"zhangsan","123");
        return user;
    }
}

🌴web.xml配置🎯Spring

web.xml如下

<?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">
    
	<!-- spring配置 -> 上下文 -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:spring/applicationContext*.xml</param-value>
    </context-param>
    <!-- 监听器 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

applicationContext.xml 如下其中配置了注册中心🎯zookeeper 其IP和端口为node1:2181 为本地启动的zookeeper 后面测试运行前会说明

<?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://dubbo.apache.org/schema/dubbo" xmlns:context="http://www.springframework.org/schema/context"
	   xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

	<!--<context:component-scan base-package="com.bigbigmengeng.service" />-->
	<!--<dubbo:protocol port="20880" />-->
	<!--dubbo的配置-->
	<!-- 1 配置项目的名称 唯一 -->
	<dubbo:application name="dubbo-service"/>
	<!-- 2 🎯配置注册中心的地址 -->
	<dubbo:registry address="zookeeper://node1:2181"/>
	<!-- 3 配置dubbo包扫描 -->
	<dubbo:annotation package="com.bigbigmeng.service.impl" />

	<!-- 元数据配置 -->
	<dubbo:metadata-report address="zookeeper://node1:2181" />
</beans>

🍭dubbo-web模块

🌴提供的服务

package com.bigbigmeng.controller;

import com.bigbigmeng.pojo.User;
import com.bigbigmeng.service.UserService;
import org.apache.dubbo.config.annotation.Reference; // 🎯远程注入
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("/user")
public class UserController {

    //注入Service
    //@Autowired  // 以前 我们使用本地注入的方式进行注入

    /*
        1. 从zookeeper注册中心获取userService的访问url
        2. 进行远程调用RPC
        3. 将结果封装为一个代理对象。给变量赋值
     */

    @Reference // 🎯远程注入
    private UserService userService;
    
    @RequestMapping("/helloWorld")
    public String helloWorld(){
        return userService.helloWorld();
    }
    /**
     * 根据id查询用户信息
     * @param id
     * @return
     */
    @RequestMapping("/findUserById")
    public User findUserById(int id){
        return userService.findUserById(id);
    }
}

🌴web配置Servlet（🎯SpringMVC）

<?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">

	<!-- 🎯Springmvc -->
    <servlet>
        <servlet-name>springmvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 指定加载的配置文件 通过参数contextConfigLocation加载 -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring/springmvc.xml</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <!-- 🎯访问链接的时候要以 .do 结尾才可以生效 -->
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>
</web-app>

🌴springmvc.xml配置如下

其中配置了注册中心🎯zookeeper 其IP和端口为node1:2181 为本地启动的zookeeper 后面测试运行前会说明

<?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://dubbo.apache.org/schema/dubbo"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
         http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd">

    <mvc:annotation-driven/>
    <context:component-scan base-package="com.bigbigmeng.controller"/>

    <!--dubbo的配置-->
    <!-- 1 配置项目的名称 唯一 -->
    <dubbo:application name="dubbo-web" >
        <dubbo:parameter key="qos.port" value="33333"/>
    </dubbo:application>
    <!-- 2 🎯配置注册中心的地址 -->
    <dubbo:registry address="zookeeper://node1:2181"/>
    <!-- 3 配置dubbo包扫描 -->
    <dubbo:annotation package="com.bigbigmeng.controller" />
</beans>

⚡启动测试

关于zookeeper

安装zookeeper见 -> Linux软件安装我在本地CentOS虚拟机上安装并启动设置虚拟机主机名为node1

本地启动

启动项目进行测试

启动dubbo-service模块

启动dubbo-web模块

浏览器访问

到此一个简单的Dubbo的使用Demo就完成啦~ very nice✨