【Java知识点大全】(十五)

// 线程池隔离
    @HystrixCommand(groupKey = "productServiceSinglePool", // 服务名称，相同名称使用同一个线程池
            commandKey = "selectProductById",              // 接口名称，默认为方法名
            threadPoolKey = "productServiceSinglePool",    // 线程池名称，相同名称使用同一个线程池
            commandProperties = {
                    // 超时时间，默认1000ms
                    @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "5000")
            },
            threadPoolProperties = {
                 // 线程池大小
                    @HystrixProperty(name = "coreSize", value = "10"),
                    // 等待队列长度（最大队列长度，默认值-1）
                    @HystrixProperty(name = "maxQueueSize", value = "100"),
                     // 线程存活时间，默认1min
                    @HystrixProperty(name = "keepAliveTimeMinutes", value = "2"),
                    // 超出等待队列阈值执行拒绝策略
                    @HystrixProperty(name = "queueSizeRejectionThreshold", value = "100")
            },
            fallbackMethod = "selectProductByIdFallBack"
    )
    @Override
    public Product selectProductById(Integer id) {
        System.out.println(Thread.currentThread().getName());
        return productClient.selectProductById(id);
    }
    private Product selectProductByIdFallBack(Integer id) {
        return new Product(888, "未知商品", 0, 0d);
    }
    // 线程池隔离
    @HystrixCommand(groupKey = "productServiceListPool", // 服务名称，相同名称使用同一个线程池
            commandKey = "selectByIds",              // 接口名称，默认为方法名
            threadPoolKey = "productServiceListPool",    // 线程池名称，相同名称使用同一个线程池
            commandProperties = {
            // 超时时间，默认1000ms
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "5000")
            },
            threadPoolProperties = {
                 // 线程池大小
                    @HystrixProperty(name = "coreSize", value = "5"),
                    // 等待队列长度（最大队列长度，默认值-1）
                    @HystrixProperty(name = "maxQueueSize", value = "100"),
                     // 线程存活时间，默认1min
                    @HystrixProperty(name = "keepAliveTimeMinutes", value = "2"),
                    // 超出等待队列阈值执行拒绝策略
                    @HystrixProperty(name = "queueSizeRejectionThreshold", value = "100")
            },
            fallbackMethod = "selectByIdsFallback"
    )
    @Override
    public List<Product> selectByIds(List<Integer> ids) {
        System.out.println(Thread.currentThread().getName());
        return productClient.selectPhoneList(ids);
    }
    private List<Product> selectByIdsFallback(List<Integer> ids) {
        System.out.println("==call method selectByIdsFallback==");
        return Arrays.asList(new Product(999, "未知商品", 0, 0d));
    }

// 服务熔断
    @HystrixCommand(
            commandProperties = {
          // 请求数阈值：在快照时间窗口内，必须满足请求阈值数才有资格熔断。打开断路器的最少请求数，默认20个请求。
          //意味着在时间窗口内，如果调用次数少于20次，即使所有的请求都超时或者失败，断路器都不会打开
                    @HystrixProperty(name = HystrixPropertiesManager.
                      CIRCUIT_BREAKER_REQUEST_VOLUME_THRESHOLD, value = "10"),
                    // 错误百分比阈值：当请求总数在快照内超过了阈值，且有一半的请求失败，这时断路器将会打开。默认50%
                    @HystrixProperty(name = HystrixPropertiesManager.
                      CIRCUIT_BREAKER_ERROR_THRESHOLD_PERCENTAGE, value = "50"),
                    // 快照时间窗口：断路器开启时需要统计一些请求和错误数据，统计的时间范围就是快照时间窗口，默认5秒
                    @HystrixProperty(name = HystrixPropertiesManager.
                      CIRCUIT_BREAKER_SLEEP_WINDOW_IN_MILLISECONDS, value = "5000")
            },
            fallbackMethod = "selectProductByIdFallBack"
    )
    @Override
    public Product selectProductById(Integer id) {
        System.out.println(Thread.currentThread().getName()+
        LocalDateTime.now().format(DateTimeFormatter.ISO_LOCAL_TIME));
        if (id == 1) {
            throw new RuntimeException("模拟查询ID为1导致异常");
        }
        return productClient.selectProductById(id);
    }

// 服务降级
@HystrixCommand(fallbackMethod = "selectProductByIdFallBack")
@Override
public Product selectProductById(Integer id) {
    System.out.println(Thread.currentThread().getName()+
    LocalDateTime.now().format(DateTimeFormatter.ISO_LOCAL_TIME));
    if (id == 1) {
        throw new RuntimeException("模拟查询ID为1导致异常");
    }
    return productClient.selectProductById(id);
}

public Product selectProductByIdFallback(){
    return new Product(999, "undefined", 0, 0d);
}

feign.hystrix.enabled=true

@FeignClient(value = "service-hi",fallback = SchedualServiceHiHystric.class)
public interface SchedualServiceHi {
    @RequestMapping(value = "/hi",method = RequestMethod.GET)
    String sayHiFromClientOne(@RequestParam(value = "name") String name);
}

@Component
public class SchedualServiceHiHystric implements SchedualServiceHi {
    @Override
    public String sayHiFromClientOne(String name) {
        return "sorry "+name;
    }
}

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

management:
  endpoints:
    web:
      exposure:
        include: hystrix.stream

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

// 开启数据监控
@EnableHystrixDashboard
// 开启熔断器
@EnableHystrix
// 开启缓存注解
@EnableCaching
@EnableFeignClients
@SpringBootApplication
public class ServiceConsumerApplication
{
    public static void main( String[] args )
    {
        SpringApplication.run(ServiceConsumerApplication.class);
    }
}

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

server:
  port: 8181
spring:
  application:
    name: eureka-turbine
eureka:
  instance:
    prefer-ip-address: true
    instance-id: ${spring.cloud.client.ip-address}:${server.port}
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/
turbine:                                            # 聚合监控
  app-config: service-consumer,service-provider     # 监控的服务列表
  cluster-name-expression: "'default'"              # 指定集群名称

@EnableTurbine
@EnableHystrix
@EnableHystrixDashboard
@SpringBootApplication
public class App
{
    public static void main( String[] args )
    {
        SpringApplication.run(App.class);
    }
}