1. pom
1) normal
<dependency>
<groupId>io.github.resilience4j</groupId>
<artifactId>resilience4j-circuitbreaker</artifactId>
<version>0.13.2</version>
</dependency>
<dependency>
<groupId>io.github.resilience4j</groupId>
<artifactId>resilience4j-retry</artifactId>
<version>0.13.2</version>
</dependency>
2) spring boot
<dependency>
<groupId>io.github.resilience4j</groupId>
<artifactId>resilience4j-spring-boot</artifactId>
<version>0.13.2</version>
</dependency>
<dependency>
<groupId>io.github.resilience4j</groupId>
<artifactId>resilience4j-retry</artifactId>
<version>0.13.2</version>
</dependency>
3) spring boot2
<dependency>
<groupId>io.github.resilience4j</groupId>
<artifactId>resilience4j-spring-boot2</artifactId>
<version>0.13.2</version>
</dependency>
<dependency>
<groupId>io.github.resilience4j</groupId>
<artifactId>resilience4j-retry</artifactId>
<version>0.13.2</version>
</dependency>
2. create CB
1) CircuitBreakerRegistry
（1）default
CircuitBreakerRegistry circuitBreakerRegistry = CircuitBreakerRegistry.ofDefaults(); // Get a CircuitBreaker from the CircuitBreakerRegistry with the global default configuration
CircuitBreaker circuitBreaker2 = circuitBreakerRegistry.circuitBreaker("myCB2");
（2）custom
// Create a custom configuration for a CircuitBreaker
CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom()
.failureRateThreshold(50)
.waitDurationInOpenState(Duration.ofMillis(1000))
.ringBufferSizeInHalfOpenState(2)
.ringBufferSizeInClosedState(2)
.build(); // Create a CircuitBreakerRegistry with a custom global configuration
CircuitBreakerRegistry circuitBreakerRegistry = CircuitBreakerRegistry.of(circuitBreakerConfig); // Get a CircuitBreaker from the CircuitBreakerRegistry with a custom configuration
CircuitBreaker circuitBreaker = circuitBreakerRegistry.circuitBreaker("myCB1", circuitBreakerConfig);
2) directly
(1) default
CircuitBreaker defaultCircuitBreaker = CircuitBreaker.ofDefaults("myCB2");
// Create a Retry with at most 3 retries and a fixed time interval between retries of 500ms
Retry retry = Retry.ofDefaults("myCB2");
(2) custom
// Create a custom configuration for a CircuitBreaker
CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom()
.failureRateThreshold(50)
.waitDurationInOpenState(Duration.ofMillis(1000))
.ringBufferSizeInHalfOpenState(2)
.ringBufferSizeInClosedState(2)
.build(); CircuitBreaker customCircuitBreaker = CircuitBreaker.of("myCB1", circuitBreakerConfig); // Create a Retry with at most 3 retries and a fixed time interval between retries of 500ms
Retry retry = Retry.ofDefaults("myCB1");
3. decorate
1) backend
// Simulates a Backend Service
public interface BackendService {
String doSomething();
}
2) Attached
// Decorate your call to BackendService.doSomething() with a CircuitBreaker
Supplier<String> decoratedSupplier = CircuitBreaker
.decorateSupplier(circuitBreaker, backendService::doSomething); // Decorate your call with automatic retry
decoratedSupplier = Retry
.decorateSupplier(retry, decoratedSupplier);
4. Exec(可选)
注意：这部分主要用来测试的！实际代码中可以忽略
1) vavr
// Execute the decorated supplier and recover from any exception
String result = Try.ofSupplier(decoratedSupplier)
.recover(throwable -> "Hello from Recovery").get(); System.out.println(result);
2) lambda expression
// When you don't want to decorate your lambda expression,
// but just execute it and protect the call by a CircuitBreaker.
String result = circuitBreaker.executeSupplier(backendService::doSomething); System.out.println(result);