dubbo 实战之三：使用 Zookeeper 注册中心，java 后端工程师面试题
package com.bolingcavalry.springbootzkprovider;
import com.bolingcavalry.dubbopractice.service.DemoService;
import lombok.extern.slf4j.Slf4j;
import org.apache.dubbo.config.annotation.Service;
import org.apache.dubbo.rpc.RpcContext;
@Slf4j
@Service
public class DemoServiceImpl implements DemoService {
@Override
public String sayHello(String name) {
log.info("I'm springboot-zk-provider, Hello " + name + ", request from consumer: " + RpcContext.getContext().getRemoteAddress());
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
return "I'm springboot-zk-provider, Hello " + name + ", response from provider: " + RpcContext.getContext().getLocalAddress();
}
}
编写 SpringBoot 启动类 SpringBootZKProviderApplication.java，注意要添加 @EnableDubbo 注解：
package com.bolingcavalry.springbootzkprovider;
import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@EnableDubbo
public class SpringBootZKProviderApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootZKProviderApplication.class, args);
}
}
至此服务提供方编码完成，直接在 IDEA 上运行 SpringBootZKProviderApplication 类即可启动服务，启动成功后的日志输出如下图，如红框所示，已连上了 Zookeeper：
[](
)编码(服务消费方)
现在网络上已经有了服务，咱们再来编写服用消费方的代码，一共要创建 6 个文件，创建顺序和功能如下表：
| 创建顺序 | 文件名 | 作用 |
| --- | --- | --- |
| 1 | pom.xml | 工程的 pom 文件 |
| 2 | src/main/resources/application.yml | 配置文件 |
| 3 | RemoteInvokeServiceImpl.java | service 层，在这里远程调用服务提供方的服务 |
| 4 | DemoController.java | web 接口类，对外提供 web 服务 |
| 5 | SwaggerConfig.java | swagger 配置类，便于通过页面测试接口 |
| 6 | SpringBootZKConsumerApplication.java | 启动类 |
完整的文件位置如下图：
接下来逐个创建上述文件；
创建名为 springbootzkconsumer 的子工程，pom.xml 内容如下，同样需要依赖 dubbo-spring-boot-starter 和 dubbo-dependencies-zookeeper：
<?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>dubbopractice</artifactId>
<groupId>com.bolingcavalry</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<groupId>com.bolingcavalry</groupId>
<artifactId>springbootzkconsumer</artifactId>
<version>1.0-SNAPSHOT</version>
<name>springbootzkconsumer</name>
<description>Demo project for dubbo service consumer from Spring Boot</description>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-dependencies</artifactId>
<version>2.3.3.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
</dependency>
<dependency>
<groupId>com.bolingcavalry</groupId>
<artifactId>practiceinterface</artifactId>
<version>${project.version}</version>
</dependency>
<dependency>
<groupId>org.apache.dubbo</groupId>
<artifactId>dubbo-dependencies-zookeeper</artifactId>
<type>pom</type>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<dependency>
<groupId>org.apache.dubbo</groupId>
<artifactId>dubbo-spring-boot-starter</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${springboot.version}</version>
</plugin>
</plugins>
</build>
</project>
编写配置文件 application.yml，注意 dubbo.registry.address 的值：
dubbo:
application:
#application-name 本模块名字
name: springboot-zk-consumer
registry:
address: zookeeper://192.168.50.43:2181
server:
port: 8081
编写调用远程服务的代码，如下，可见如果想调用远程服务，只要对接口做 @Reference 注释即可，另外还通过 timeout 属性增加了超时配置：
package com.bolingcavalry.springbootzkconsumer.service;
import com.bolingcavalry.dubbopractice.service.DemoService;
import org.apache.dubbo.config.annotation.Reference;
import org.springframework.stereotype.Service;
@Service
public class RemoteInvokeServiceImpl {
@Reference(timeout = 2000)
private DemoService demoService;
public String sayHello(String name) {
return "from dubbo remote (zk registry center mode) : " + demoService.sayHello(name);
}
}
再编写对外提供 web 服务的 Controller 类：
package com.bolingcavalry.springbootzkconsumer.controller;
import com.bolingcavalry.springbootzkconsumer.service.RemoteInvokeServiceImpl;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("/demo")
@Api(tags = {"DemoController"})
public class DemoController {
@Autowired
private RemoteInvokeServiceImpl remoteInvokeService;
@ApiOperation(value = "获取 dubbo service provider 的响应", notes=""获取 dubbo service provider 的响应")
@ApiImplicitParam(name = "name", value = "昵称", paramType = "path", required = true, dataType = "String")
@RequestMapping(value = "/{name}", method = RequestMethod.GET)
public String sayHello(@PathVariable String name){
return remoteInvokeService.sayHello(name);
}
}
还要添加 swagger 配置类：
package com.bolingcavalry.springbootzkconsumer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.service.Tag;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2;
@Configuration
@EnableSwagger2
public class SwaggerConfig {
@Bean
public Docket createRestApi() {
return new Docket(DocumentationType.SWAGGER_2)
.apiInfo(apiInfo())
.tags(new Tag("DemoController", "演示服务"))
.select()
// 当前包路径
.apis(RequestHandlerSelectors.basePackage("com.bolingcavalry.springbootzkconsumer.controller"))
.paths(PathSelectors
.any())
.build();
}
//构建 api 文档的详细信息函数,注意这里的注解引用的是哪个
private ApiInfo apiInfo() {
return new ApiInfoBuilder()
//页面标题
.title("dubbo 远程调用服务的操作(zk 注册中心)")
//创建人
.contact(new Contact("程序员欣宸", "https://github.com/zq2599/blog_demos", "zq2599@gmail.com"))
//版本号
.version("1.0")
//描述
.description("API 描述")
.build();
}
}
最后是启动类 SpringBootZKConsumerApplication.java：
package com.bolingcavalry.springbootzkconsumer;
import org.apache.dubbo.config.spring.context.annotation.EnableDubbo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@EnableDubbo
public class SpringBootZKConsumerApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootZKConsumerApplication.class, args);
}
}
至此，服务消费方编码完成，直接在 IDEA 上运行 SpringBootZKConsumerApplication 类即可启动，如下图，可见服务消费方也连接 Zookeeper 成功：
通过浏览器访问 swagger，地址是：http://localhost:8081/swagger-ui.html ，如下图，点击红框位置展开接口详情：
如下图，输入 web 接口参数发起请求：
下图红框中就是响应的数据，内容是 springbootzkconsumer 远程调用 springbootzkprovider 的服务得到的：
[](
)查看 Zookeeper 上的数据
再回顾一下官方的有关 Zookeeper 注册中心中数据的描述，如下图：
按照上述信息，咱们去 Zookeeper 看看数据，验证和上图是否一致，登录 Zookeeper 后执行 zkCli.sh 进度交互模式；
查看根目录，果然有名为 dubbo 的子目录：
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