Java多线程学习心得

线程的概念：

大白话的意思就是，线程存在于进程中，它主要是为了提进程中CPU（进程有内存，线程没有）的利用率，即提高效率。

主线程：执行main方法的线程，是它产生其他线程，通常它是最后结束，因为它要执行关闭其他线程的工作，它不会直接关闭其他线程，而只是发送指令过去。

java实现多线程的方式

1. 继承Thread类
2. 实现Runnable接口
3. 实现Callable接口

java基础学习时实现多线程的方式主要学习前面两种，callable是后面产生的

下面通过一个案例来理解多线程：模拟烧水，洗茶杯与泡茶过程

Demo1:

package test;

import java.util.concurrent.CountDownLatch;

public class ThreadTest {

	private static boolean isok = false; 
	static final CountDownLatch countdown = new CountDownLatch(1);
	
	
	public static void main(String[] args) {
		
		final Object lock = new Object();
		
		Thread washThread = new Thread(new Runnable() {
			public void run() {
				for(int i=1;i<=5;i++) {
					
					System.out.println("washing："+i);
					try {
						Thread.sleep(1500);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					if(i==3) {
						System.out.println("发出通知");
						countdown.countDown();
					}
				}
			}
			
		},"washthread");
		
		Thread boilThread = new Thread(new Runnable() {

			public void run() {
				
					try {
						countdown.await();
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("收到通知...make tea...");
			}
			
		},"boilthread");
		
		washThread.start();
		boilThread.start();
	}
}
           

Demo2:

package test;

import java.util.concurrent.CountDownLatch;

public class ThreadTest {

	private static boolean isok = false; 
	static final CountDownLatch countdown = new CountDownLatch(2);
	
	
	public static void main(String[] args) {
		
		final Object lock = new Object();
		
		Thread washThread = new Thread(new Runnable() {
			public void run() {
				for(int i=1;i<=5;i++) {
					
					System.out.println("washing："+i);
					try {
						Thread.sleep(1500);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				System.out.println("发出通知");
				countdown.countDown();
			}
			
		},"washthread");
		
		Thread boilThread = new Thread(new Runnable() {

			public void run() {
				
					try {
						Thread.sleep(5000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("收到通知...make tea...");
					countdown.countDown();
			}
			
		},"boilthread");
		Thread maketeaThread = new Thread(new Runnable() {

			public void run() {
				
					try {
						countdown.await();
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println("收到通知... 喝茶...");
			}
			
		},"maketeathread");
		washThread.start();
		boilThread.start();
		maketeaThread.start();
	}
}