/*
* Thread thread = new Thread() // 第一种方法new 它的子类 {
*
* @Override public void run() { while (true) { try {
* Thread.sleep(1000); } catch (InterruptedException e) {
* e.printStackTrace(); }
* System.out.println(Thread.currentThread().getName());
* System.out.println("------------------------------");
* System.out.println(this.getName()); } } }; thread.start();
*
* Thread thread2 = new Thread(new Runnable() // new 传一个runnable
* 这种方式更面向对象些 {
*
* @Override public void run() { while (true) { try {
* Thread.sleep(1000); } catch (InterruptedException e) {
* e.printStackTrace(); }
* System.out.println(Thread.currentThread().getName());
* System.out.println("------------------------------"); } } });
*
* thread2.start();
*/
定时器的写法
Timer timer = new Timer();
timer.schedule(new TimerTask() {
@Override
public void run() {
System.out.println("bombing");
}
}, 10000,3000);
while (true) {
System.out.println(new Date().getSeconds());
try { Thread.sleep(1000); }
catch (InterruptedException e)
{
e.printStackTrace();
} }
定时器的每隔2秒与4秒交替出现一句话
private static int count = 0;
public static void main(String[] args) { class myTimerTask extends TimerTask { @Override public void run() { count = (count + 1) % 2; System.out.println("bombing"); new Timer().schedule(new myTimerTask(), 2000 + 2000 * count); } }
Timer timer = new Timer(); timer.schedule(new myTimerTask(), 2000);
while (true) { System.out.println(new Date().getSeconds()); try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } }
线程的安全
package cn.itcast.day5.thread;
public class TraditionThreadSynchronized { public static void main(String[] args) { new TraditionThreadSynchronized().init(); }
private void init() { final Outputer outputer = new Outputer(); new Thread(new Runnable() { @Override public void run() { while (true) { try { Thread.sleep(0); } catch (InterruptedException e) { e.printStackTrace(); } outputer.output("peterpeng"); } } }).start();
new Thread(new Runnable() { @Override public void run() { while (true) { try { Thread.sleep(0); } catch (InterruptedException e) { e.printStackTrace(); } outputer.output2("yangyang"); } } }).start(); }
static class Outputer { String xxx = "";
public void output(String name) { int len = name.length(); synchronized (xxx) // 这里就是用来一个线程跑完再跑另一个线。xxx:也就可以用this,但最好的方法是下面的写法 // 一定要是同一个对象,不能用name因为是两个对象,而outputer是同一个对象,如果new // outputer().output("yanyang")又会出问题，因为这样两个名不一样，是不同的对象 { for (int i = 0; i < len; i++) { System.out.print(name.charAt(i)); } System.out.println(); } }
public synchronized void output1(String name)// 这里是线程安全的写法，一定只能有一个synchronized，否则会死锁 { int len = name.length(); { for (int i = 0; i < len; i++) { System.out.print(name.charAt(i)); } System.out.println(); } }
public static synchronized void output2(String name)// 这里是线程安全的写法，一定只能有一个synchronized，否则会死锁 { int len = name.length(); { for (int i = 0; i < len; i++) { System.out.print(name.charAt(i)); } System.out.println(); } }
// 说明如果调用output 与output2 // 又会出问题，因为两个又不是同一个对象了。要解决这个问题，可以升级到字节码在output中把xxx换成 Output.class就可以了 } }