多线程

线程简介

用户自己写的线程：用户线程
JVM的线程：守护线程

线程创建（线程开启并不一定立即执行，由cpu调度）

1. 继承Thread类

public class ExtendThread extends Thread {
 
	private int i;
	
	public static void main(String[] args) {
		for(int j = 0;j < 50;j++) {
			
			//调用Thread类的currentThread()方法获取当前线程
			System.out.println(Thread.currentThread().getName() + " " + j);
			
			if(j == 10) {
				//创建并启动第一个线程
				new ExtendThread().start();
				
				//创建并启动第二个线程
				new ExtendThread().start();
			}
		}
	}
 
	public void run() {
		for(;i < 100;i++) {
			//当通过继承Thread类的方式实现多线程时，可以直接使用this获取当前执行的线程
			System.out.println(this.getName() + " "  + i);
		}
	}
}

2. 实现Runnable接口

public class ImpRunnable implements Runnable {
	
	private int i;
	
	@Override
	public  void run() {
		for(;i < 50;i++) {	
			//当线程类实现Runnable接口时，要获取当前线程对象只有通过Thread.currentThread()获取
			System.out.println(Thread.currentThread().getName() + " " + i);
		}
	}
 
	public static void main(String[] args) {
		for(int j = 0;j < 30;j++) {
			System.out.println(Thread.currentThread().getName() + " " + j);
			if(j == 10) {
				ImpRunnable thread_target = new ImpRunnable();
				//通过new Thread(target,name)的方式创建线程
				new Thread(thread_target,"线程1").start();
				new Thread(thread_target,"线程2").start();
			}
			
		}
 
	}
 
}

3. 实现Callable接口

import java.util.concurrent.*;

public class Thread3 implements Callable<Boolean> {
    private int tictets=10;
    @Override
    public Boolean call() throws Exception{
        if(Thread.currentThread().getName()=="小明")
        {
            try {
                Thread.sleep(20);
            } catch (InterruptedException e) {
                e.printStackTrace();
                System.out.printf("出现异常");
            }
        }
        while(true)
        {
            if(tictets<=0) break;
            System.out.println(Thread.currentThread().getName()+"拿到了第"+tictets--+"张票");
        }
        return true;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        Thread3 t1=new Thread3();
        Thread3 t2=new Thread3();
        ExecutorService ser= Executors.newFixedThreadPool(2);
        Future<Boolean> r1= ser.submit(t1);
        Future<Boolean> r2= ser.submit(t2);
        boolean rs1= r1.get();
        boolean rs2=r2.get();
        System.out.printf(String.valueOf(rs1));
        System.out.printf(String.valueOf(rs2));
        ser.shutdown();

    }
}