Guava Retryer如何实现长尾词策略的重试机制？

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在 `pom.xml` 文件中添加依赖项，格式如下：

xml com.google.guava guava RELEASE compile com.github.rholder guava-retrying 2.0.0

pom.xml

<dependency> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> <version>RELEASE</version> <scope>compile</scope> </dependency> <dependency> <groupId>com.github.rholder</groupId> <artifactId>guava-retrying</artifactId> <version>2.0.0</version> <!-- 排除与guava重复的依赖 --> <exclusions> <exclusion> <groupId>com.google.guava</groupId> <artifactId>guava</artifactId> </exclusion> <exclusion> <groupId>com.google.code.findbugs</groupId> <artifactId>jsr305</artifactId> </exclusion> </exclusions> </dependency>

code

public static void main(String[] args) { String msg = "aaabbb"; Callable<Integer> task = new Callable<Integer>() { @Override public Integer call() throws Exception { System.out.println("length:".concat(msg.length() + "")); return msg.length(); } }; //返回异常或返回6或返回null，都会触发重试机制。最多执行4次（首次 + 重试3次），每次延迟5s。 Retryer<Integer> retryer = RetryerBuilder.<Integer>newBuilder() .retryIfResult(Predicates.<Integer>isNull()) .retryIfResult(Predicates.equalTo(6)) .retryIfExceptionOfType(Exception.class) .withStopStrategy(StopStrategies.stopAfterAttempt(4)) .withWaitStrategy(WaitStrategies.fixedWait(5*1000, TimeUnit.MILLISECONDS)) .build(); try { retryer.call(task); } catch (ExecutionException e) { e.printStackTrace(); } catch (RetryException e) { log.error("重试3次依旧未能获得期望值"); // e.printStackTrace(); } }