使用resilience4j-retry实现函数式重试

<dependency>
    <groupId>io.github.resilience4j</groupId>
    <artifactId>resilience4j-retry</artifactId>
    <version>0.13.2</version>
</dependency>
<dependency>
    <groupId>io.github.resilience4j</groupId>
    <artifactId>resilience4j-core</artifactId>
    <version>0.13.2</version>
</dependency>

// Given the HelloWorldService returns Hello world
given(helloWorldService.returnHelloWorld())
    .willReturn(completedFuture("Hello world"));

final AsyncRetry retryContext = AsyncRetry.of("retryConfig",
        // we set the response type to String
        RetryConfig.<String>custom()
                // max retry attempts
                .maxAttempts(3)
                // what are the ignore exception to no retry on
                .ignoreExceptions(IllegalStateException.class)
                // what are the exceptions to try on
                .retryExceptions(TimeoutException.class)
                // retry if the response contains world
                .retryOnResult(s -> s.contains("world"))
                // retry backoff strategy, IntervalFunction has many built in interface functions you can check it out
                .intervalFunction(IntervalFunction.ofExponentialBackoff())
                .build());

// Decorate the invocation of the HelloWorldService
Supplier<CompletionStage<String>> supplier = AsyncRetry.decorateCompletionStage(
            retryContext,
            scheduler,
            () -> helloWorldService.returnHelloWorld());

// When
String result = awaitResult(supplier);
// Then the helloWorldService should be invoked 1 time
BDDMockito.then(helloWorldService).should(Mockito.times(3)).returnHelloWorld();
Assertions.assertEquals(result, "Hello world");

// Given the HelloWorldService returns Hello world
BDDMockito.given(helloWorldService.returnHelloWorld()).willReturn("Hello world");
// Create a Retry with default configuration
final RetryConfig tryAgain = RetryConfig.<String>custom().retryOnResult(s -> s.contains("Hello world"))
                .maxAttempts(2).build();
Retry retry = Retry.of("id", tryAgain);
// Decorate the invocation of the HelloWorldService
Supplier<String> supplier = Retry.decorateSupplier(retry, helloWorldService::returnHelloWorld);
// When
String result = supplier.get();
// Then the helloWorldService should be invoked 1 time
BDDMockito.then(helloWorldService).should(Mockito.times(2)).returnHelloWorld();
assertThat(result).isEqualTo("Hello world");