65、springCloud入门 | 易学教程

springCloud：微服务的实现方式。

组件：

Eureka：注册中心

Zuul：服务网关

Ribbon：负载均衡

Feign：服务调用

Hystrix：熔断器

入门代码

前提：父工程为springboot，并且进行了jar包的版本管理

Eureka：注册中心，实现服务的注册和发现功能

1、导入坐标

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    </dependency>
    <dependency>
        <groupId>org.glassfish.jaxb</groupId>
        <artifactId>jaxb-runtime</artifactId>
        <version>2.3.2</version>
    </dependency>
</dependencies>

2、创建启动类

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

3、添加配置文件

server:
  port: 8084

spring:
  application:
    name: eureka-server

eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:8084/eureka

Ribbon：负载均衡

Hystrix：熔断器

Feign：服务调用

Zuul：服务网关

示例代码：

1、导入坐标

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

    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
</dependencies>

2、编写启动类

@EnableCircuitBreaker
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients


/*
@SpringCloudApplication
*/
public class ConsumerApplication {

    @Bean
    @LoadBalanced

    public RestTemplate restTemplate (){
        return  new RestTemplate();
    }

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

3、实现代码

@RestController
@RequestMapping("consumer")
public class ConsumerController {
    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private LoadBalancerClient client;

    @GetMapping("{id}")
    @HystrixCommand(fallbackMethod = "queryByIdFallback")
    public Account queryById(@PathVariable ("id") Integer id){

        //List<ServiceInstance> instances = discoveryClient.getInstances("user_service");
        //ServiceInstance instanceInfo = instances.get(0);

        ServiceInstance instance = client.choose("user_service");

        String url = "http://"+instance.getHost()+":"+instance.getPort()+"/account/"+id;
        System.out.println(url);
        Account account = restTemplate.getForObject(url,Account.class);
        return account;
    }

    public Account queryByIdFallback(Integer id ){
        return null;
    }
}

来源：https://my.oschina.net/u/4131739/blog/3106807

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springcloud入门