Java多執行緒三種主要實現方式解析
阿新 • • 發佈:2020-07-21
多執行緒三種主要實現方式:繼承Thread類,實現Runnable介面、Callable和Futrue。
一、簡單實現
import java.util.concurrent.Callable; import java.util.concurrent.ExecutionException; import java.util.concurrent.FutureTask; import java.util.concurrent.TimeUnit; public class T02_HowToCreateThread { //1.繼承Thread類 static class MyThread extends Thread{ @Override public void run() { System.out.println("MyThread-->"); } } //3.實現Runnable介面 static class MyRun implements Runnable{ @Override public void run() { System.out.println("MyRunable-->"); } } //4.實現Callable介面 static class MyCall implements Callable{ @Override public Object call() throws Exception { System.out.println("myCallable-->"); return 1; } } public static void main(String[] args) throws ExecutionException,InterruptedException { //1.繼承Thread類 new MyThread().start(); //2.lambda與繼承Thread類類//1.繼承Thread類似,最簡單 new Thread(()->{ System.out.println("lambda-->"); }).start(); //3.實現Runnable介面 new Thread(new MyRun()).start(); new Thread(new Runnable() { @Override public void run() { System.out.println("simple->Runnable"); } }).start(); //4.實現Callable介面,並用包裝器FutureTask來同時實現Runable、Callable兩個介面,可帶返回結果 MyCall mycall = new MyCall(); FutureTask futureTask = new FutureTask(mycall); new Thread(futureTask).start(); System.out.println(futureTask.get()); } }
二、使用ExecutorService、Callable和Future一起實現帶返回值
import java.util.ArrayList; import java.util.List; import java.util.concurrent.*; /** * 使用ExecutorsService、Callable、Future來實現多個帶返回值的執行緒 */ public class T02_HowToCreateThread02 { static class MyCallable implements Callable{ private int taskNum; public MyCallable(int taskNum){ this.taskNum = taskNum; } @Override public Object call() throws Exception { System.out.println("任務"+taskNum); return "MyCallable.call()-->task"+taskNum; } } public static void main(String[] args) throws ExecutionException,InterruptedException { int num = 5; //建立一個執行緒池 ExecutorService pool = Executors.newFixedThreadPool(num); List<Future> futureList = new ArrayList<Future>(); for (int i = 0; i < num; i++){ MyCallable mc = new MyCallable(i); //執行任務,並返回值 Future future = pool.submit(mc); futureList.add(future); } pool.shutdown(); for (Future f: futureList){ System.out.println(f.get()); } } }
結果:
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