Java中创建线程的几种方式

底层都是基于实现Runnable接口

1.继承thread类，new一个thread对象，实现run方法，无返回值

public class MyThread extends Thread {@Overridepublic void run() {System.out.println("Thread created by extending Thread class is running.");}public static void main(String[] args) {MyThread myThread = new MyThread();myThread.start();}
}

2.实现Runnable接口，new一个thread对象，实现run方法，无返回值

public class MyRunnable implements Runnable {@Overridepublic void run() {System.out.println("Thread created by implementing Runnable interface is running.");}public static void main(String[] args) {MyRunnable myRunnable = new MyRunnable();Thread thread = new Thread(myRunnable);thread.start();}
}

3.实现Callable接口，new一个thread对象

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;public class MyCallable implements Callable<String> {@Overridepublic String call() throws Exception {return "Thread created by implementing Callable interface is running.";}public static void main(String[] args) {MyCallable myCallable = new MyCallable();FutureTask<String> futureTask = new FutureTask<>(myCallable);Thread thread = new Thread(futureTask);thread.start();try {String result = futureTask.get();System.out.println(result);} catch (InterruptedException | ExecutionException e) {e.printStackTrace();}}
}

4.线程池，实现Runnable接口

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;public class WebCrawler {private static final int THREAD_POOL_SIZE = 10;public static void main(String[] args) {List<String> urls = new ArrayList<>();urls.add("https://example.com/page1");urls.add("https://example.com/page2");urls.add("https://example.com/page3");// 添加更多的URLExecutorService executorService = Executors.newFixedThreadPool(THREAD_POOL_SIZE);for (String url : urls) {executorService.execute(new CrawlTask(url));}executorService.shutdown();try {executorService.awaitTermination(1, TimeUnit.HOURS);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("All tasks completed.");}static class CrawlTask implements Runnable {private final String url;CrawlTask(String url) {this.url = url;}@Overridepublic void run() {try {URL urlObj = new URL(url);BufferedReader reader = new BufferedReader(new InputStreamReader(urlObj.openStream()));String inputLine;StringBuilder content = new StringBuilder();while ((inputLine = reader.readLine()) != null) {content.append(inputLine);}reader.close();// 假设这里我们将内容存储到数据库storeInDatabase(content.toString());System.out.println("Crawled: " + url);} catch (Exception e) {e.printStackTrace();}}private void storeInDatabase(String content) {// 实现存储逻辑System.out.println("Storing content from: " + url);}}
}