SpringCloud之Feign路由、负载和熔断

yzm4399

已于 2022-03-21 09:56:17 修改

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分类专栏： spring cloud 文章标签： spring cloud

于 2022-03-15 09:20:52 首次发布

本文链接：https://blog.youkuaiyun.com/qq_43654581/article/details/123493487

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该博客展示了如何在Spring Cloud中使用Feign进行服务间的调用，并实现熔断降级。通过创建feign-ha和feign-hi两个服务，配置Eureka注册中心，启用Hystrix熔断器，当服务不可用时，调用回退方法。同时，演示了负载均衡和路由转发功能。

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1、服务feign-ha

在这里插入图片描述

<?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>com.yzm</groupId>
        <artifactId>springcloud</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>

    <artifactId>feign-ha</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>feign-ha</name>
    <description>Demo project for Spring Boot</description>

    <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>
    </dependencies>

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

</project>

application.yml

server:
  port: 8094

spring:
  application:
    name: feign-ha

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8088/eureka/
#启用熔断机制
feign:
  hystrix:
    enabled: true

启动类

@EnableFeignClients
@EnableEurekaClient
@SpringBootApplication
public class FeignHaApplication {
	...
}

Controller

@RestController
public class HaController {

    @Resource
    private HaFeign haFeign;

    @Value("${server.port}")
    private String port;

    @GetMapping("hello")
    public String hello(@RequestParam String name) {
        return "ha，" + name + " ! " + "访问端口号：" + port;
    }

    @GetMapping("ha")
    public String ha(@RequestParam String name) {
        return haFeign.callHi(name);
    }

}

Service

// 请求转发到 feign-hi 服务，服务不可达时，回调Haback
@FeignClient(value = "feign-hi", fallback = HaBack.class)
public interface HaFeign {

    @GetMapping("hello")
    String callHi(@RequestParam String name);
}

@Service
public class HaBack implements HaFeign {
    @Override
    public String callHi(String name) {
        return "feign-hi 服务挂了";
    }
}

2、服务feign-hi

在这里插入图片描述

<?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>com.yzm</groupId>
        <artifactId>springcloud</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <relativePath>../pom.xml</relativePath>
    </parent>

    <artifactId>feign-hi</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>feign-hi</name>
    <description>Demo project for Spring Boot</description>

    <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>
    </dependencies>

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

</project>

application.yml

server:
  port: 8095

spring:
  application:
    name: feign-hi

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8088/eureka/

feign:
  hystrix:
    enabled: true

启动类

@EnableFeignClients
@EnableEurekaClient
@SpringBootApplication
public class FeignHiApplication {
	...
}

Controller

@RestController
public class HiController {

    @Resource
    private HiFeign hiFeign;

    @Value("${server.port}")
    private String port;

    @GetMapping("hello")
    public String hello(@RequestParam String name) {
        return "hi，" + name + " ! " + "访问端口号：" + port;
    }

    @GetMapping("hi")
    public String hi(@RequestParam String name) {
        return hiFeign.callHa(name);
    }

}

Service

@FeignClient(value = "feign-ha", fallback = HiBack.class)
public interface HiFeign {

    @GetMapping("hello")
    String callHa(@RequestParam String name);
}

@Service
public class HiBack implements HiFeign {
    @Override
    public String callHa(String name) {
        return "feign-ha 服务挂了";
    }
}

3、路由转发

依次启动eureka、feign-ha、feign-hi
访问 http://localhost:8095/hi?name=yzm
在这里插入图片描述
转发成功！

4、负载均衡

启动feign-hi:18095服务
刷新 http://localhost:8094/ha?name=yzm
在这里插入图片描述

负载成功！

5、熔断降级

关闭feign-ha:8094服务
访问 http://localhost:8095/hi?name=yzm
在这里插入图片描述
熔断成功！