Beispiele für Java ScheduledExecutorService
In Java können wirScheduledExecutorService verwenden, um eine Aufgabe regelmäßig oder einmal nach einer vordefinierten Verzögerung vonTimeUnit auszuführen.
1. Führen Sie eine Aufgabe einmal aus
DieScheduledExecutorService akzeptieren sowohlRunnable als auchCallable Aufgaben.
1.1 Run a Runnable task after 5 seconds initial delay.
ScheduledExecutorExample.java
package com.example.concurrency.executor.scheduler;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
public class ScheduledExecutorRunnable {
public static void main(String[] args) {
ScheduledExecutorService ses = Executors.newScheduledThreadPool(1);
Runnable task2 = () -> System.out.println("Running task2...");
task1();
//run this task after 5 seconds, nonblock for task3
ses.schedule(task2, 5, TimeUnit.SECONDS);
task3();
ses.shutdown();
}
public static void task1() {
System.out.println("Running task1...");
}
public static void task3() {
System.out.println("Running task3...");
}
}
Ausgabe
Running task1... Running task3... Running task2... //display after 5 seconds
1.2 Run a Callable task after 5 seconds initial delay.
ScheduledExecutorExample.java
package com.example.concurrency.executor.scheduler;
import java.util.concurrent.*;
public class ScheduledExecutorCallable {
public static void main(String[] args) throws InterruptedException, ExecutionException {
ScheduledExecutorService ses = Executors.newScheduledThreadPool(1);
Callable task2 = () -> 10;
task1();
//run this task after 5 seconds, nonblock for task3, returns a future
ScheduledFuture schedule = ses.schedule(task2, 5, TimeUnit.SECONDS);
task3();
// block and get the result
System.out.println(schedule.get());
System.out.println("shutdown!");
ses.shutdown();
}
public static void task1() {
System.out.println("Running task1...");
}
public static void task3() {
System.out.println("Running task3...");
}
}
Ausgabe
Running task1... Running task3... 10 //display after 5 seconds shutdown!
2. Führen Sie regelmäßig eine Aufgabe aus
Verwenden SiescheduleAtFixedRate, um eine Aufgabe regelmäßig auszuführen
2.1 Run a Runnable task every 1 second, after 5 seconds initial delay.
ScheduledExecutorExample.java
package com.example.concurrency.executor.scheduler;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
public class ScheduledExecutorRepeat {
private static int count = 0;
public static void main(String[] args) throws InterruptedException {
ScheduledExecutorService ses = Executors.newScheduledThreadPool(1);
Runnable task1 = () -> {
count++;
System.out.println("Running...task1 - count : " + count);
};
// init Delay = 5, repeat the task every 1 second
ScheduledFuture scheduledFuture = ses.scheduleAtFixedRate(task1, 5, 1, TimeUnit.SECONDS);
while (true) {
System.out.println("count :" + count);
Thread.sleep(1000);
if (count == 5) {
System.out.println("Count is 5, cancel the scheduledFuture!");
scheduledFuture.cancel(true);
ses.shutdown();
break;
}
}
}
}
Ausgabe
count :0 count :0 count :0 count :0 count :0 Running...task1 - count : 1 count :1 Running...task1 - count : 2 count :2 Running...task1 - count : 3 count :3 Running...task1 - count : 4 count :4 Running...task1 - count : 5 Count is 5, cancel the scheduledFuture!
Quellcode herunterladen
$ git clone https://github.com/example/java-concurrency.git