SpringCloud災難性雪崩效應處理方法之降級實現(xiàn)流程詳解

更新時間：2022年11月29日 16:08:21 作者：小蝦仁蕪湖

這篇文章主要介紹了SpringCloud災難性雪崩效應處理方法之降級，文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值，需要的朋友們下面隨著小編來一起學習吧<BR>

一.前言

解決服務雪崩效應，都是避免application client請求application service時，出現(xiàn)服務調(diào)用錯誤或網(wǎng)絡問題。處理手法都是在application client中實現(xiàn)。我們需要在application client相關工程中導入hystrix依賴信息。并在對應的啟動類上增加新的注解@EnableCircuitBreaker，這個注解是用于開啟hystrix熔斷器的，簡言之，就是讓代碼中的hystrix相關注解生效。

二.代碼實現(xiàn)

1.新建ApplicationServiceDemo

1.1配置pom.xml

需要web和eureka-client

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.5.RELEASE</version>
</parent>
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Hoxton.SR9</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.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
</dependencies>

1.2新建配置文件

spring:
application:
name: application-service-demo
eureka:
client:
service-url:
defaultZone: http://eurekaserver1:8761/eureka/

1.3新建控制器

@Controller
public class DemoController {
    @RequestMapping("/demo")
    @ResponseBody
    public String demo(){
        return "demo-service";
    }
}

1.4新建啟動類

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

2.新建DemoFallback

新建項目DemoFallback作為Application Client

2.1編寫pom.xml

需要配置web,eureka-client,netflix-hystrix

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.3.5.RELEASE</version>
</parent>
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Hoxton.SR9</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.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>
</dependencies>

2.2新建配置文件

spring:
application:
name: fallback-demo
eureka:
client:
service-url:
defaultZone: http://eurekaserver1:8761/eureka/
server:
port: 8081

2.3新建配置類

@Configuration
public class RibbonConfig {
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

2.4新建service及實現(xiàn)類

public interface DemoService {
    String test();
}

@Service
public class DemoServiceImpl implements DemoService {
    @Autowired
    private RestTemplate restTemplate;
    @HystrixCommand(fallbackMethod = "myFallback")
    @Override
    public String test() {
        String result = restTemplate.postForObject("http://application-service-demo/demo", null, String.class);
        System.out.println(result);
        return result;
    }
    public String myFallback(){
        return "托底數(shù)據(jù)";
    }
}

2.5新建控制器

@Controller
public class FallbackController {
    @Autowired
    private DemoService demoService;
    @RequestMapping("/demo")
    @ResponseBody
    public String demo(){
        return demoService.test();
    }
}

2.6新建啟動類

@SpringBootApplication
@EnableCircuitBreaker
public class ApplicationClientApplication {
    public static void main(String[] args) {
        SpringApplication.run(ApplicationclientdemoApplication.class, args);
    }
}