Java入门使用Thread入门

Java中的线程实现是通过继承java.lang.Thread类然后实现run方法；或者通过实现Runnable接口，实现run方法，然后在实例化Thread时传入此Runnable实例作为参数。

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如下代码片段 DownloadThread从Thread继承实现run方法下载一个Url：

package hello;import java.io.IOException;import org.apache.http.client.*;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.BasicResponseHandler;import org.apache.http.impl.client.DefaultHttpClient;/** * DownloadThread 从Thread继承，实现run方法 * @author yukaizhao * */public class DownloadThread extends Thread {@Overridepublic void run(){HttpClient client = new DefaultHttpClient();HttpGet httpGet = new HttpGet("http://yukaizhao.javaeye.com/");try {            // Create a response handler            ResponseHandler<String> responseHandler = new BasicResponseHandler();String responseBody = client.execute(httpGet,responseHandler);System.out.println(responseBody);} catch (ClientProtocolException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}}

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如下代码片段，实现Runnable，休眠随机毫秒数，然后输出一行文本

package hello;import java.util.Random;/** * 实现Runnable，实现run方法 * @author yukaizhao * */public class RunnableImpl implements Runnable {static int _number = 0;public void run(){Random random = new Random();int sleepMm=random.nextInt(200);try {Thread.sleep(sleepMm);} catch (InterruptedException e) {e.printStackTrace();}System.out.println(String.format("I'm %1d thread",++_number));}}

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如下代码，在main函数中调用线程实现：

package hello;public class HelloThread {public static void main(String[] args) throws InterruptedException{//声明Thread变量DownloadThread thread = new DownloadThread();//调用run执行方法thread.run();//join等待thread执行完毕的信号thread.join();//声明RunnableRunnable[] impls = new Runnable[5];//声明Runnable数量相同的线程Thread[] threads = new Thread[impls.length];for(int i=0;i<impls.length;i++){impls[i] = new RunnableImpl();//将Runnable的实例作为参数传递给Thread的构造函数threads[i] = new Thread(impls[i]);//启动线程threads[i].start();}}}