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在spring cloud建构的微服务架构中，多个微服务有时需要统一配置信息，这时我们可以建立配置服务器ralab-configserver，然后各微服务从该配置服务器获取配置信息

ralab-configserver服务器

  • New microservice ‘ralab-configserver’ and add the Maven spring-cloud-config-server denpendency
  • Add @EnableConfigServer to the application class
  • Add github repository url to application.yml file

配置服务器的pom.xml文件如下：

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-configserver</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-configserver</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR3</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-config-server</artifactId>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabConfigserverApplication文件

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package com.ralab.ralabconfigserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;

@SpringBootApplication
@EnableConfigServer
public class RalabConfigserverApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabConfigserverApplication.class, args);
    }

}

bootstrap.yml

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spring:
  application:
    name: configserver

application.yml

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server:
  port: 8888
spring:
  cloud:
    config:
      server:
        encrypt.enabled: false
        git:
          uri: https://github.com/chenying99/config-repo
          searchPaths: licensingservice,organizationservice

运行RalabConfigserverApplication，然后打开http://localhost:8888/licensingservice/default

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前面的文章，我们利用RestTemplate对象和feign组件实现了微服务之间的通信，并且通过集成Hystrix，从而实现了容错及故障恢复功能

本文主要实现对Hystrix的可视化监控

这里新建微服务’ralab-hystrix-dashboard’

  • New microsevice ralab-hystrix-dashboard and add the Maven spring-cloud-starter-netflix-hystrix-dashboard denpendency
  • Add @EnableHystrixDashboard to the application class
  • Config info to application.yml file

同时被监控的微服务

  • Add spring-boot-starter-actuator denpendency
  • Add management.endpoints.web.exposure.include=hystrix.stream parameter to the application file

微服务’ralab-hystrix-dashboard’pom.xml文件如下：

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-hystrix-dashboard</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-hystrix-dashboard</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR3</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabHystrixDashboardApplication文件

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package com.ralab.ralabhystrixdashboard;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;

@SpringBootApplication
@EnableHystrixDashboard
public class RalabHystrixDashboardApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabHystrixDashboardApplication.class, args);
    }

}

application.yml文件

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spring:
  application:
    name: hystrix-dashboard
server:
  port: 8080

运行RalabHystrixDashboardApplication，打开http://localhost:8080/hystrix

同时被监控的微服务加入依赖

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<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

曝露hystrix端点

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spring.application.name=nlp-client
server.port=8091
management.endpoints.web.exposure.include=hystrix.stream

这时在输入框输入’http://localhost:8091/actuator/hystrix.stream'，点击Monitor stream按钮，就可以看到如下页面了

注：spring cloud还提供了turbine组件对多个微服务的Hystrix信息进行聚合，从而实现对微服务cluster的Hystrix信息的可视化监控

|

上文我们采用feign组件与微服务’ralab-nlp’进行通信，在实际应用中，feign组件通过集成Hystrix，从而实现熔断机制
改造微服务’ralab-client’

  • Add the Maven spring-cloud-starter-netflix-hystrix denpendency
  • Config hystrix info to bootstrap.yml file
  • Add FeignClient fallback class by Implement EurekaFeignService Interface
    我们在前面的文章中已经添加了spring-cloud-starter-netflix-hystrix依赖
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    <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            </dependency>

bootstrap.yml

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eureka:
  instance:
    # ip-address: 127.0.0.1
    prefer-ip-address: true # 补充
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

server:
  port: 8091
management:
  endpoints:
    web:
      exposure:
        include: hystrix.stream

spring:
  application:
    name: nlp-client
  cloud:
    config:
      name: licensingservice
      profile: default
      label: master
      discovery:
        enabled: true
        service-id: configserver

feign:
  hystrix:
    enabled: true

EurekaFeignService文件

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package com.ralab.ralabclient.services;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;

@FeignClient(value = "nlp-service",fallback = EurekaFeignServiceFailure.class)
public interface EurekaFeignService {

    @RequestMapping(value = "nlp/api")
    String nlpService();
}

@Component
class EurekaFeignServiceFailure implements EurekaFeignService {
    @Override
    public String nlpService() {
        return "不好意思，feingn调用失败";
    }
}

NlpResource文件 注释@HystrixCommand注解

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package com.ralab.ralabclient.resources;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.ralab.ralabclient.services.EurekaFeignService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
@RefreshScope
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private EurekaFeignService eurekaFeignService;

    @Value("${example.property}")
    private String exampleProperty;

    @RequestMapping("/config")
    public String home() {
        return "exampleProperty:" + exampleProperty;
    }

    @GetMapping("/service")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }

    @GetMapping("/feign")
    //@HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String feignservice()
    {
        //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
        String result = eurekaFeignService.nlpService();
        return result;
    }

    private String getFallbackIndex()
    {
        //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);

        return "不好意思，没有获取到服务端信息";
    }
}

这时停止微服务’ralab-nlp’，打开http://localhost:8091/nlp/feign

|

在实际应用中，spring cloud通常feign组件与服务提供者进行通信，feign有着更友好的api调用方式
我们改造微服务’ralab-client’

  • Add the Maven spring-cloud-config-server denpendency
  • Add @EnableFeignClients to the application class
  • Add FeignClient Interface communicate to microservice ‘ralab-nlp’
  • Add invoke Interface to RestController NlpResource
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    <?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.8.RELEASE</version>
            <relativePath/> <!-- lookup parent from repository -->
        </parent>
        <groupId>com.ralab</groupId>
        <artifactId>ralab-client</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>ralab-client</name>
        <description>Demo project for Spring Boot</description>

        <properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Greenwich.SR3</spring-cloud.version>
        </properties>

        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            </dependency>       

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
            <!--添加依赖，获取配置服务器的相关配置信息-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-config</artifactId>
            </dependency>

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>${spring-cloud.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>

        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>

    </project>

RalabClientApplication文件

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package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
@EnableFeignClients
public class RalabClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

EurekaFeignService文件

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package com.ralab.ralabclient.services;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;

@FeignClient(value = "nlp-service")
public interface EurekaFeignService {

    @RequestMapping(value = "nlp/api")
    String nlpService();
}

然后在NlpResource调用上面的feign接口

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package com.ralab.ralabclient.resources;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.ralab.ralabclient.services.EurekaFeignService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
@RefreshScope
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;
    
    @Autowired
    private EurekaFeignService eurekaFeignService;

    @Value("${example.property}")
    private String exampleProperty;

    @RequestMapping("/config")
    public String home() {
        return "exampleProperty:" + exampleProperty;
    }

    @GetMapping("/service")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }

    @GetMapping("/feign")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String feignservice()
    {        
        String result = eurekaFeignService.nlpService();
        return result;
    }

    private String getFallbackIndex()
    {
        //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);

        return "不好意思，没有获取到服务端信息";
    }
}

运行RalabClientApplication，打开http://localhost:8091/nlp/feign

|

前面的文章主要探索的是微服务通信及服务发现（Communication and Discovery），接下来要解决的是容错及故障恢复（Fault Tolerance and Resilience）
当某个微服务出现故障时，确保系统能够正常运行及从故障中恢复
spring cloud采用了一种称之为断路器（Circuit breaker）的模式，本文主要演示该模式的Hystrix实现

这里是基于微服务’ralab-client’

  • Add the Maven spring-cloud-starter-netflix-hystrix denpendency
  • Add @EnableCircuitBreaker to the application class
  • Add @HystrixCommand to methods that need circuit breakers
  • configure Hystrix behavior
    其pom.xml文件如下： 
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    <?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
        <modelVersion>4.0.0</modelVersion>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.8.RELEASE</version>
            <relativePath/> <!-- lookup parent from repository -->
        </parent>
        <groupId>com.ralab</groupId>
        <artifactId>ralab-client</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>ralab-client</name>
        <description>Demo project for Spring Boot</description>

        <properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
        </properties>

        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            </dependency>

            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            </dependency>

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
        </dependencies>

        <dependencyManagement>
            <dependencies>
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>${spring-cloud.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>

        <build>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
        </build>

    </project>

RalabClientApplication文件

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package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
public class RalabClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

NlpResource文件

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package com.ralab.ralabclient.resources;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/service")
    @HystrixCommand(fallbackMethod = "getFallbackIndex")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }

    private String getFallbackIndex()
    {
        //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);

        return "不好意思，没有获取到服务端信息";
    }
}

先停止微服务’ralab-nlp’，重新运行RalabClientApplication，测试http://localhost:8091/nlp/service

上面利用Hystrix实现了微服务’ralab-client’的容错及故障恢复功能，在其需要容错的方法上，还可以自定义相关参数，这里不再演示

|

建立注册服务器（ralab-server）并服务提供者（ralab-nlp）向其注册后，这时服务消费者（ralab-client，服务消费者也向注册服务器注册）可以通过访问注册服务器，查找服务实例名的方式查找服务提供者的相关信息，然后调用其服务

这里基于微服务’ralab-client’

  • Add @LoadBalanced to the RestTemplate Instance
  • Edit RestTemplate url parameter host as ‘nlp-service’

服务消费者ralab-client
RalabClientApplication文件

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package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
public class RalabClientApplication {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

修改NlpResource文件

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package com.ralab.ralabclient.resources;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/service")
    public String index()
    {
      //String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      String result = restTemplate.getForObject("http://nlp-service/nlp/api", String.class);
      return result;
    }
}

运行RalabClientApplication

测试http://localhost:8091/nlp/service

|

这里基于微服务’ralab-nlp’和’ralab-client’

  • Add the Maven spring-cloud-starter-netflix-eureka-client denpendency
  • Add @EnableEurekaClient to the application class
  • Add spring.application.name parameter to the application.properties file

这时修改服务提供者ralab-nlp的pom.xml文件，引入eureka-client依赖

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-nlp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-nlp</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

修改RalabNlpApplication文件

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package com.ralab.ralabnlp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.ComponentScan;

//(scanBasePackages = { "com.ralab.nlp.controller"})
//@ComponentScan({"com.ralab.nlp.controller"})
@SpringBootApplication
@EnableEurekaClient
public class RalabNlpApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabNlpApplication.class, args);
    }

}

修改application.properties文件
spring.application.name=nlp-service
server.port=8090

运行RalabNlpApplication

同时修改服务消费者ralab-client的pom.xml文件，引入eureka-client依赖

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

修改RalabClientApplication文件

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package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
public class RalabClientApplication {

    @Bean
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

修改application.properties文件
spring.application.name=nlp-client
server.port=8091

运行RalabClientApplication

这时在浏览器打开http://localhost:8761/

可以看到注册实例nlp-service和nlp-client

|

前两文中的建立的项目，在逻辑上可分为服务提供者（ralab-nlp）和服务消费者（ralab-client），服务消费者采用RestTemplate与之通信
在spring cloude中，采用了服务注册的方式，所有的服务提供者及服务消费者都向注册服务器注册，然后服务消费者从注册服务器上查询相关服务

微服务’ralab-server’

  • New microservice ‘ralab-server’ and add the Maven spring-cloud-starter-netflix-eureka-server denpendency
  • Add @EnableEurekaServer to the application class

本文建立注册服务器（注册服务器ralab-server），引入eureka-server依赖，pom.xml文件如下：

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-server</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabServerApplication文件

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package com.ralab.ralabserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class RalabServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabServerApplication.class, args);
    }

}

运行RalabServerApplication

打开浏览器http://localhost:8761/

这时没有发现注册实例

|

上文采用spring boot建立了restful项目，本文建立新的项目，并处理与之通信
先设置上文应用程序的端口，resources文件夹application.properties
server.port=8090

微服务’ralab-client’

  • New mocroservice ‘ralab-client’ and add the Maven spring-boot-starter-web denpendency
  • Add server.port parameter to the application.properties file
  • Add RestTemplate instance to Communicate with mocroservice ‘ralab-nlp’ by url

新建maven项目（服务消费者ralab-client），引入spring-web依赖，pom.xml文件如下：

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-client</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

RalabClientApplication文件

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package com.ralab.ralabclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
public class RalabClientApplication {

    @Bean
    public RestTemplate getRestTemplate()
    {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(RalabClientApplication.class, args);
    }

}

新建NlpResource

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package com.ralab.ralabclient.resources;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/nlp")
public class NlpResource {

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/service")
    public String index()
    {
      String result = restTemplate.getForObject("http://localhost:8090/nlp/api", String.class);
      return result;
    }
}

设置端口
resources文件夹application.properties
server.port=8091

运行RalabClientApplication

测试http://localhost:8091/nlp/service

|

微服务’ralab-nlp’

  • New mocroservice ‘ralab-nlp’ and add the Maven spring-boot-starter-web denpendency
  • Add @SpringBootApplication to the application class
  • Add HelloController

本文采用maven建立应用程序（服务提供者ralab-nlp），引入spring-web依赖，pom.xml配置如下

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<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.ralab</groupId>
    <artifactId>ralab-nlp</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>ralab-nlp</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <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>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

自动生成RalabNlpApplication.java代码

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package com.ralab.ralabnlp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

//(scanBasePackages = { "com.ralab.nlp.controller"})
@SpringBootApplication
@ComponentScan({"com.ralab.nlp.controller"})
public class RalabNlpApplication {

    public static void main(String[] args) {
        SpringApplication.run(RalabNlpApplication.class, args);
    }

}

新建HelloController.java

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package com.ralab.nlp.controller;


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

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

@RestController
@RequestMapping("/nlp")
public class HelloController {

    @GetMapping("/api")
    public String index() {
        return "Greetings from Spring Boot!";
    }
}

运行RalabNlpApplication

测试http://localhost:8080/nlp/api