Java请求重试机制Guava-retrying

1，添加依赖

<dependency>
            <groupId>com.github.rholder</groupId>
            <artifactId>guava-retrying</artifactId>
            <version>2.0.0</version>
        </dependency>

2，重试机制的策略设置

Retryer<Boolean> retryer = RetryerBuilder.<Boolean>newBuilder().
              
                        retryIfException().
              
                        retryIfResult(Predicates.equalTo(false)).
          
                        withWaitStrategy(WaitStrategies.fixedWait(3, TimeUnit.SECONDS)).
              
                        withStopStrategy(StopStrategies.stopAfterAttempt(3)).
    
                        withRetryListener(new MyRetryListener()).build();

（1）retryIfException：遇到异常重试
（2）retryIfException: 返回结果为false重试
（3）withWaitStrategy(WaitStrategies.fixedWait(3, TimeUnit.SECONDS))：等待3秒重试一次
（4）withStopStrategy(StopStrategies.stopAfterAttempt(3))：重试三次
（5）withRetryListener(new MyRetryListener()).build()：MyRetryListener为自定义的重试监听类，监听重试成功失败的信息
3，案例
（1）需要重试的业务类

import java.util.concurrent.Callable;

/**
 * @author LiHaitao
 * @description MyCallable:
 * @date 2019/8/6 11:02
 **/
public class MyCallable implements Callable {
    private static int i = 0;

    @Override
    public Boolean call() throws Exception {
        i++;
        if (i <= 2) {
            throw new Exception("重试次数达:" + i);
        }
        System.out.println("成功");
        return true;
    }
}

（2）监听类

import com.github.rholder.retry.Attempt;
import com.github.rholder.retry.RetryListener;

/**
 * @author LiHaitao
 * @description MyRetryListener:
 * @date 2019/8/6 11:00
 **/
public class MyRetryListener implements RetryListener {

    @Override
    public <V> void onRetry(Attempt<V> attempt) {
        System.out.print("[retry]time=" + attempt.getAttemptNumber());
    
        System.out.print(",delay=" + attempt.getDelaySinceFirstAttempt());

        // 重试结果: 是异常终止, 还是正常返回
        System.out.print(",hasException=" + attempt.hasException());
        System.out.print(",hasResult=" + attempt.hasResult());

        // 导致异常的原因
        if (attempt.hasException()) {
            System.out.print(",causeBy=" + attempt.getExceptionCause().toString());
        } else {
            // 正常返回时的结果
            System.out.print(",result=" + attempt.getResult());
        }
    }
}

（3）启动类

import com.github.rholder.retry.Retryer;
import com.github.rholder.retry.RetryerBuilder;
import com.github.rholder.retry.StopStrategies;
import com.github.rholder.retry.WaitStrategies;
import com.google.common.base.Predicates;

import java.util.concurrent.TimeUnit;

/**
 * @author LiHaitao
 * @description Main:
 * @date 2019/8/6 11:02
 **/
public class Main {

    public static void main(String[] args) {
        Retryer<Boolean> retryer = RetryerBuilder.<Boolean>newBuilder().
              
                        retryIfException().
                
                        retryIfResult(Predicates.equalTo(false)).
              
                        withWaitStrategy(WaitStrategies.fixedWait(3, TimeUnit.SECONDS)).
                
                        withStopStrategy(StopStrategies.stopAfterAttempt(3)).
                
                        withRetryListener(new MyRetryListener()).build();
        try {
            Boolean call = retryer.call(new MyCallable());//在此加入任务
        } catch (Exception e) {
                       System.out.println(e.getMessage());

        }

    }
}