SpringCloud学习笔记（三），Hystix熔断、Feign以及ZUUL网关学习总结

1. Hystix是Netflix开源的一个延迟和容错库，用于隔离访问远程服务、第三方库，防止出现级联失败。
2. 工作机制

简单来讲就是针对！！！！！！

<dependency>

    <groupId>org.springframework.cloud</groupId>

    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>

</dependency>

使用@SpringBootApplication

@EnableDiscoveryClient

@EnableCircuitBreaker

或者使用@SpringCloudApplication代替前三个

因为这是一个混合注解包括前三个

该注解源码

@Target({ElementType.TYPE})

@Retention(RetentionPolicy.RUNTIME)

@Documented

@Inherited

@SpringBootApplication

@EnableDiscoveryClient

@EnableCircuitBreaker

public @interface SpringCloudApplication {

}

@GetMapping("/{userId}")

    @HystrixCommand(

            //声明一个失败回滚处理函数

            fallbackMethod = "fallback01",

            commandProperties={

            //更改超时时间，默认1000 /1秒，针对当前方法使用

            @HystrixProperty(name="execution.isolation.thread.timeoutInMilliseconds",value="1000")

    }

)

 public UserInfo findById(@PathVariable("userId") int userId) {

        System.out.println("这是消费端接收的ID是 " + userId);

        String url = "http://user-service/" + userId ;

        System.out.println("Url"+url);

       UserInfo userInfo = restTemplate.getForObject(url, UserInfo.class);

        System.out.println("消费者接收的数据"+userInfo.getUsername());

       return userInfo ;

    }

//下面就是fallbackMethod 指定的方法

//下面@PathVariable("userId")在该方法有没有不影响   

public UserInfo fallback01( @PathVariable("userId") int userId) {

        System.out.println("接收的参数ID是："+userId);

        UserInfo userInfo = new UserInfo();

        userInfo.setUserId(110);

        userInfo.setUsername("服务器炸了！");

        return userInfo;

    }

配置全局超时时间

没成功

2.1 添加依赖

<dependency>

    <groupId>org.springframework.cloud</groupId>

    <artifactId>spring-cloud-starter-openfeign</artifactId>

</dependency>

2.2 编写接口

@FeignClient("user-service")

public interface UserFeignClient {

    @GetMapping("/{userId}")

    UserInfo findById(@PathVariable int userId);

}

2.3 启动类配置

添加注解

@SpringCloudApplication

3ff7 @EnableFeignClients

public class UserConsumerApplication {

    //Feign中已经自动集成了Ribbon负载均衡，因此我们不需要自己定义RestTemplate了。    /*@Bean

    @LoadBalanced

    public RestTemplate restTemplate(){

        return new RestTemplate();

    }*/

    public static void main(String[] args) {

        SpringApplication.run(UserConsumerApplication.class, args);

    }

}

2.4 客户端调用

@RestController

@DefaultProperties(defaultFallback = "fallback01")

public class UserController {

    @Autowired

    private UserFeignClient userFeignClient ;

    @GetMapping("/{userId}")

    public UserInfo findById(@PathVariable("userId") int userId) {

        return userFeignClient.findById(userId);

    }

    /*@Autowired

    private RestTemplate restTemplate;*/

    /*@GetMapping("/{userId}")

    @HystrixCommand(

            //指定请求超时后去响应其他方法

            fallbackMethod = "fallback01",

            commandProperties={

            //更改超时时间，默认1000 /1秒

            @HystrixProperty(name="execution.isolation.thread.timeoutInMilliseconds",value="1000")

    }

    )

    public UserInfo findById(@PathVariable("userId") int userId) {

        System.out.println("这是消费端接收的ID是 " + userId);

        String url = "http://user-service/" + userId ;

        System.out.println("Url"+url);

       UserInfo userInfo = restTemplate.getForObject(url, UserInfo.class);

        System.out.println("消费者接收的数据"+userInfo.getUsername());

       return userInfo ;

    }*/

    public UserInfo fallback01( int userId) {

        System.out.println("接收的参数ID是："+userId);

        UserInfo userInfo = new UserInfo();

        userInfo.setUserId(110);

        userInfo.setUsername("服务器炸了！");

        return userInfo;

    }

}

2.5 负载均衡

Feign中本身已经集成了Ribbon依赖和自动配置

2.6 Feign对Hystix支持

Feign默认也有对Hystix的集成，只不过，默认情况下是关闭的

开启Hystix配置：feign.hystrix.enabled=true

2.6.1 编写熔断器实现接口

//这是个组件

@Component

public class UserFallBack implements UserFeignClient {

    @Override

    public UserInfo findById(int userId) {

        UserInfo userInfo = new UserInfo();

        userInfo.setUserId(110);

        userInfo.setUsername("这是采用Feign对Hystix的支持实现的熔断器");

        return userInfo;

    }

}

@FeignClient(value = "user-service",fallback = UserFallBack.class)

public interface UserFeignClient {

    @GetMapping("/{userId}")

    UserInfo findById(@PathVariable int userId);

}

3.1 添加依赖

<dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>

        </dependency>

@SpringBootApplication

@EnableZuulProxy

public class GatewayApplication {

    public static void main(String[] args) {

        SpringApplication.run(GatewayApplication.class, args);

    }

}

server.port=10086

spring.application.name=gateway

server.port=10086

spring.application.name=gateway

#eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka

#路由配置

#如果不写映射规则，系统会提供一套默认的配置规则

#映射路径

zuul.routes.user-service.path=/user-service/**

#映射路径实际对应的url

zuul.routes.user-service.url=http://127.0.0.1:8081

zuul.routes.user-service.serviceId=user-service

4.1 添加依赖

<dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

</dependency>

@SpringBootApplication

@EnableZuulProxy

@EnableDiscoveryClient

public class GatewayApplication {

    public static void main(String[] args) {

        SpringApplication.run(GatewayApplication.class, args);

    }

}

server.port=10086

spring.application.name=gateway

eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka

#路由配置

#如果不写映射规则，系统会提供一套默认的配置规则

#映射路径

zuul.routes.user-service.path=/user-service/**

#映射路径实际对应的url

#zuul.routes.user-service.url=http://127.0.0.1:8081

zuul.routes.user-service.serviceId=user-service

#将以上的url，更改为serviceId，不再面向于IP地址，更改为面向于服务，通过Eureka自动查找对应的服务名称，底层会应用负载均衡，实现服务的调用。

server.port=10086

spring.application.name=gateway

eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka

#映射路径

zuul.routes.user-service.path=/user-service/**

#设置忽略服务的集合a,b,c

zuul.ignored-services=user-consumer