熔斷器是什么？
當某個機器接口失敗率達到某一條件（比如失敗率>50%），就可以采用熔斷器將服務器從集群機器中移除，或者采用自定義的業務邏輯降級方案，比如從一個接口轉到另一個接口。熔斷器只是一個工具，重要的是業務邏輯。

1.hystrics

2.resilience4j（輕量級熔斷框架）

Resilience4j-輕量級熔斷框架
resilience4j.
Resilience4j是一款輕量級，易于使用的容錯庫，其靈感來自于Netflix Hystrix，但是專為Java 8和函數式編程而設計。輕量級，因為庫只使用了Vavr，它沒有任何其他外部依賴下。相比之下，Netflix Hystrix對Archaius具有編譯依賴性，Archaius具有更多的外部庫依賴性，例如Guava和Apache Commons Configuration。

要使用Resilience4j，不需要引入所有依賴，只需要選擇你需要的。

Resilience4j提供了以下的核心模塊和拓展模塊:

核心模塊：

• resilience4j-circuitbreaker: Circuit breaking
• resilience4j-ratelimiter: Rate limiting
• resilience4j-bulkhead: Bulkheading
• resilience4j-retry: Automatic retrying (sync and async)
• resilience4j-cache: Result caching
• resilience4j-timelimiter: Timeout handling

CircuitBreaker（熔斷器）

// Create a custom configuration for a CircuitBreaker CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom().failureRateThreshold(50).slowCallRateThreshold(50).waitDurationInOpenState(Duration.ofMillis(1000)).slowCallDurationThreshold(Duration.ofSeconds(2)).permittedNumberOfCallsInHalfOpenState(3).minimumNumberOfCalls(10).slidingWindowType(SlidingWindowType.TIME_BASED).slidingWindowSize(5).recordException(e -> INTERNAL_SERVER_ERROR.equals(getResponse().getStatus())).recordExceptions(IOException.class, TimeoutException.class).ignoreExceptions(BusinessException.class, OtherBusinessException.class).build();// Create a CircuitBreakerRegistry with a custom global configuration CircuitBreakerRegistry circuitBreakerRegistry CircuitBreakerRegistry.of(circuitBreakerConfig);// Get or create a CircuitBreaker from the CircuitBreakerRegistry // with the global default configuration CircuitBreaker circuitBreakerWithDefaultConfig = circuitBreakerRegistry.circuitBreaker("name1");// Get or create a CircuitBreaker from the CircuitBreakerRegistry // with a custom configuration CircuitBreaker circuitBreakerWithCustomConfig = circuitBreakerRegistry.circuitBreaker("name2", circuitBreakerConfig); // Create a custom configuration for a CircuitBreaker CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom().failureRateThreshold(50).slowCallRateThreshold(50).waitDurationInOpenState(Duration.ofMillis(1000)).slowCallDurationThreshold(Duration.ofSeconds(2)).permittedNumberOfCallsInHalfOpenState(3).minimumNumberOfCalls(10).slidingWindowType(SlidingWindowType.TIME_BASED).slidingWindowSize(5).recordException(e -> INTERNAL_SERVER_ERROR.equals(getResponse().getStatus())).recordExceptions(IOException.class, TimeoutException.class).ignoreExceptions(BusinessException.class, OtherBusinessException.class).build();// Create a CircuitBreakerRegistry with a custom global configuration CircuitBreakerRegistry circuitBreakerRegistry CircuitBreakerRegistry.of(circuitBreakerConfig);// Get or create a CircuitBreaker from the CircuitBreakerRegistry // with the global default configuration CircuitBreaker circuitBreakerWithDefaultConfig = circuitBreakerRegistry.circuitBreaker("name1");// Get or create a CircuitBreaker from the CircuitBreakerRegistry // with a custom configuration CircuitBreaker circuitBreakerWithCustomConfig = circuitBreakerRegistry.circuitBreaker("name2", circuitBreakerConfig);You can add configurations which can be shared by multiple CircuitBreaker instances.JavaCircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom().failureRateThreshold(70).build();circuitBreakerRegistry.addConfiguration("someSharedConfig", config);CircuitBreaker circuitBreaker = circuitBreakerRegistry.circuitBreaker("name", "someSharedConfig"); CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom().failureRateThreshold(70).build();circuitBreakerRegistry.addConfiguration("someSharedConfig", config);CircuitBreaker circuitBreaker = circuitBreakerRegistry.circuitBreaker("name", "someSharedConfig");You can overwrite configurations.JavaCircuitBreakerConfig defaultConfig = circuitBreakerRegistry.getDefaultConfig();CircuitBreakerConfig overwrittenConfig = CircuitBreakerConfig.from(defaultConfig).waitDurationInOpenState(Duration.ofSeconds(20)).build();CircuitBreakerConfig defaultConfig = circuitBreakerRegistry.getDefaultConfig();CircuitBreakerConfig overwrittenConfig = CircuitBreakerConfig.from(defaultConfig).waitDurationInOpenState(Duration.ofSeconds(20)).build(); If you don’t want to use the CircuitBreakerRegistry to manage CircuitBreaker instances, you can also create instances directly.Java// Create a custom configuration for a CircuitBreaker CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom().recordExceptions(IOException.class, TimeoutException.class).ignoreExceptions(BusinessException.class, OtherBusinessException.class).build();CircuitBreaker customCircuitBreaker = CircuitBreaker.of("testName", circuitBreakerConfig); // Create a custom configuration for a CircuitBreaker CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom().recordExceptions(IOException.class, TimeoutException.class).ignoreExceptions(BusinessException.class, OtherBusinessException.class).build();CircuitBreaker customCircuitBreaker = CircuitBreaker.of("testName", circuitBreakerConfig);

Timelimiter（超時控制）

Bulkhead（1.基于信號量 2.基于有等待隊列的固定大小的線程池）

RateLimiter（限流）

Fallback

Retry（重試）

Sentinel 與 Hystrix、resilience4j 的對比

總結

以上是生活随笔為你收集整理的熔断策略的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。