2020-04-08重试相关

guava-retrying

1.如果抛出 IOException 则重试，如果返回结果为 null 或者等于 2 则重试，固定等待时长为 300 ms,最多尝试 3 次；

Callable task = new Callable() {
    @Override
    public Integer call() throws Exception {
        return 2;
    }
};

Retryer retryer = RetryerBuilder.newBuilder()
        .retryIfResult(Predicates.isNull())
        .retryIfResult(Predicates.equalTo(2))
        .retryIfExceptionOfType(IOException.class)
        .withStopStrategy(StopStrategies.stopAfterAttempt(3))
        .withWaitStrategy(WaitStrategies.fixedWait(300, TimeUnit.MILLISECONDS))
        .build();
try {
    retryer.call(task);
} catch (ExecutionException e) {
    e.printStackTrace();
} catch (RetryException e) {
    e.printStackTrace();
}

2.出现异常则执行重试，每次任务执行最长执行时间限定为 3 s，重试间隔时间初始为 3 s，最多重试 1 分钟，随着重试次数的增加每次递增 1 s，每次重试失败，打印日志；

Callable task = new Callable() {
    @Override
    public Integer call() throws Exception {
        return 2;
    }
};

Retryer retryer = RetryerBuilder.newBuilder()
        .retryIfException()
        .withStopStrategy(StopStrategies.stopAfterDelay(30,TimeUnit.SECONDS))
        .withWaitStrategy(WaitStrategies.incrementingWait(3, TimeUnit.SECONDS,1,TimeUnit.SECONDS))
        .withAttemptTimeLimiter(AttemptTimeLimiters.fixedTimeLimit(3,TimeUnit.SECONDS))
        .withRetryListener(new RetryListener() {
            @Override
            public  void onRetry(Attempt attempt) {
                if (attempt.hasException()){
                    attempt.getExceptionCause().printStackTrace();
                }
            }
        })
        .build();
try {
    retryer.call(task);
} catch (ExecutionException e) {
    e.printStackTrace();
} catch (RetryException e) {
    e.printStackTrace();
}