【多线程】Thread的常用方法

Thread的常用方法

1.构造器

public class Demo01 {public static void main(String[] args) {//public Thread(String name); 创建线程对象并设置线程名称MyThread t1 = new MyThread("火车");t1.start();//public Thread(Runnable target); 封装Runnable对象成为线程对象Thread t2 = new Thread(new MyRunnable(), "高铁");t2.start();}
}//线程实现方式一
class MyThread extends Thread {public MyThread(){}//子类将名称直接交给父类的构造器初始化public MyThread(String name) {super(name);}@Overridepublic void run() {//public void run(); 封装线程任务的方法for (int i = 1; i <= 10; i++) {//public String getName(); 获取线程名称System.out.println(getName() + "：" + i);}}
}//线程实现方式二
class MyRunnable implements Runnable {@Overridepublic void run() {for (int i = 1; i <= 10; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}
}

2.方法

public class Demo02 {public static void main(String[] args) {MyThread t1 = new MyThread();//public void setName(); 设置线程名称t1.setName("火车");//public void start(); 启动线程t1.start();//public Thread(Runnable target); 封装Runnable对象成为线程对象Thread t2 = new Thread(new MyRunnable(), "高铁");t2.start();}
}//线程实现方式一
class MyThread extends Thread {@Overridepublic void run() {//public void run(); 封装线程任务的方法for (int i = 1; i <= 10; i++) {//public String getName(); 获取线程名称System.out.println(getName() + "：" + i);}}
}//线程实现方式二
class MyRunnable implements Runnable {@Overridepublic void run() {for (int i = 1; i <= 10; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}
}

public class Demo03 {public static void main(String[] args) throws InterruptedException {//public static void sleep(long time); 让当前执行的线程,休眠指定毫秒后继续运行
//        System.out.println("测试开始");
//        Thread.sleep(3000);
//        System.out.println("测试开始");//public final void join(); 让调用这个方法的线程，启动后优先执行完毕//Java中如何控制三个线程，按指定顺序执行完毕（三个方法启动后都加join，调整顺序即可实现）Thread t3 = new Thread(() -> {for (int i = 1; i <= 5; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "线程3");t3.start();t3.join(); Thread t2 = new Thread(() -> {for (int i = 1; i <= 5; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "线程2");t2.start();t2.join(); Thread t1 = new Thread(() -> {for (int i = 1; i <= 5; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "线程1");t1.start();t1.join(); }
}

3.补充

（1）线程分为两种调度模型

• 分时调度，所有线程轮流使用CPU，平均分配时间

• 抢占式调度：优先级高的获取CPU时间相对长一些（不是绝对），如果优先级相同会随机选择，Java中线程的调度模型为抢占式调度，在同一时刻，线程抢夺CPU的执行权是随机的

• public final void setDaemon(boolean on)：设置当前线程为守护线程，当其他线程执行完毕了，守护线程也就跟着停止了，但不是立刻

  public class Demo03 {public static void main(String[] args) {//public final void setDaemon(boolean on); 设置当前线程为守护线程new Thread(() -> {for (int i = 1; i <= 10; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "线程1").start();Thread t2 = new Thread(() -> {for (int i = 1; i <= 100; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "线程2");//public final void setDaemon(boolean on); 设置当前线程为守护线程t2.setDaemon(true);t2.start();}
  }
  

• public final void setPriority()：设置线程优先级

• public final int getPriority()：获取线程优先级

  线程优先级高仅是抢到CPU的执行权相对几率大，不是绝对的

  public static final int MIN_PRIORITY=1;最低

  public static final int NORM_PRIORITY=5;默认

  public static final int MAX_PRIORITY=10;最高

public class Demo03 {public static void main(String[] args) {Thread t1 = new Thread(() -> {for (int i = 1; i <= 10; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "飞机");//public final void setPriority();设置线程优先级//t1.setPriority(100); //数值超出了范围，抛异常 IllegalArgumentExceptiont1.setPriority(10);t1.start();Thread t2 = new Thread(() -> {for (int i = 1; i <= 10; i++) {System.out.println(Thread.currentThread().getName() + "：" + i);}}, "大炮");//System.out.println(t2.getPriority()); //默认是5t2.start();}
}