多线程学习笔记（狂神说视频21-28）
CopyOnWriteArrayList
package demo3;
import java.util.concurrent.CopyOnWriteArrayList;
//测试JUC安全类型的集合
public class TestJUC {
public static void main(String[] args) {
// TODO Auto-generated method stub
CopyOnWriteArrayList<String> list = new CopyOnWriteArrayList<String>();
for(int i=0;i<10000;i++)
{
new Thread(()->{
list.add(Thread.currentThread().getName());
}).start();
}
try {
Thread.sleep(3000);
}catch(Exception e)
{
e.printStackTrace();
}
System.out.println(list.size());
}
}
22死锁
死锁：多个线程互相抱着对方需要的资源，然后形成僵持
package demo4;
//死锁：多个线程互相抱着对方需要的资源，然后形成僵持
public class DeadLock {
public static void main(String[] args) {
// TODO Auto-generated method stub
Makeup g1 = new Makeup(1,"灰姑娘");
Makeup g2 = new Makeup(1,"白雪公主");
g1.start();
g2.start();
}
}
//口红
class Lipstick{
}
//镜子
class Mirror{
}
class Makeup extends Thread{
//需要的资源只有一份,所以用static
static Lipstick l = new Lipstick();
static Mirror m = new Mirror();
int choice;//选择
String girlName;//选择化妆品的人
Makeup(int choice,String girlName)
{
this.choice = choice;
this.girlName = girlName;
}
@Override
public void run(){
//化妆
try {
makeup();
}catch(Exception e)
{
e.printStackTrace();
}
}
//化妆,互相持有对方的锁，就是需要拿到对方的资源
private void makeup() throws InterruptedException{
if(choice==0)
{
synchronized(l)//获得口红的锁
{
System.out.println(this.girlName+"获得了口红的锁");
Thread.sleep(1000);
}
synchronized(m)//一秒钟后想获得镜子的锁
{
System.out.println(this.girlName+"获得镜子的锁");
}
}
else
{
synchronized(m)//获得镜子的锁
{
System.out.println(this.girlName+"获得了镜子的锁");
Thread.sleep(2000);
}
synchronized(l)//一秒钟后想获得口红的锁
{
System.out.println(this.girlName+"获得口红的锁");
}
}
}
}
运行结果:
Lock锁
package demo4;
import java.util.concurrent.locks.ReentrantLock;
//测试lock锁
public class TestLock {
public static void main(String[] args) {
// TODO Auto-generated method stub
TestLock2 t = new TestLock2();
new Thread(t).start();
new Thread(t).start();
new Thread(t).start();
}
}
class TestLock2 implements Runnable{
int ticketNums = 10;
//定义Lock锁
private final ReentrantLock lock = new ReentrantLock();
@Override
public void run() {
while(true)
{
try {
lock.lock();//加锁
if(ticketNums>0)
{
try {
Thread.sleep(1000);
}catch(Exception e)
{
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName()+" "+ticketNums--);
}
else
break;
}finally {
//解锁
lock.unlock();
}
}
}
}
运行结果：
24生产消费者问题
25管程法
package demo4;
//测试：生产者消费者模型-》里哟个缓冲区解决：管程法
//生产者，消费者，长跑，缓冲区
public class TestPC {
public static void main(String[] args) {
// TODO Auto-generated method stub
SynContainer c = new SynContainer();
new Productor(c).start();
new Consumer(c).start();
}
}
//生产者
class Productor extends Thread{
SynContainer container;
public Productor(SynContainer container) {
this.container = container;
}
//生产
@Override
public void run() {
for(int i=0;i<100;i++)
{
container.push(new Chicken(i));
System.out.println("生产了"+i+"只鸡");
}
}
}
//消费者
class Consumer extends Thread{
SynContainer container;
public Consumer(SynContainer container) {
this.container = container;
}
//消费
@Override
public void run() {
for(int i=0;i<100;i++)
{
System.out.println("消费了"+container.pop().id+"只鸡");
}
}
}
//产品
class Chicken{
int id;//编号
public Chicken(int id)
{
this.id = id;
}
}
//缓冲区
class SynContainer{
//容器大小
Chicken[] chickens = new Chicken[10];
//容器计数器
int count = 0;
//生产者放入产品
public synchronized void push(Chicken chicken)
{
//如果容器满了，就需要等待消费者消费
if(count == chickens.length)
{
//通知消费者消费，生产等待
try {
this.wait();
}catch(Exception e) {
e.printStackTrace();
}
}
//如果没有满，我们就需要丢入产品
chickens[count] = chicken;
count++;
//可以通知消费者了
this.notifyAll();
}
//消费者消费产品
//消费者消费产品
public synchronized Chicken pop() {
//判断能否消费
if(count==0)
{
//等待生产者生产，消费者等待
try {
this.wait();
}catch(Exception e)
{
e.printStackTrace();
}
}
//如果可以消费
count--;
Chicken chicken = chickens[count];
//吃完了，通知生产者生产
this.notifyAll();
return chicken;
}
}
运行结果：
26信号灯法
package demo4;
//测试生产消费者问题2,信号灯法，标志位解决
public class TestPC2 {
public static void main(String[] args) {
// TODO Auto-generated method stub
TV tv = new TV();
new player(tv).start();
new Watcher(tv).start();
}
}
//生产者-》演员
class player extends Thread{
TV tv;
public player(TV tv)
{
this.tv = tv;
}
@Override
public void run() {
for(int i=0;i<20;i++)
{
if(i%2==0)
{
this.tv.play("快乐大本营播放中");
}
else
{
this.tv.play("抖音记录美好生活");
}
}
}
}
//消费者-》观众
class Watcher extends Thread{
TV tv;
public Watcher(TV tv)
{
this.tv = tv;
}
@Override
public void run() {
for(int i=0;i<20;i++)
{
tv.watch();
}
}
}
//产品-》节目
class TV {
//演员表演，观众等待
//观众观看，演员等待
String voice;//表演的节目
boolean flag = true;
//表演
public synchronized void play(String voice) {
if(!flag)
{
try {
this.wait();
}catch(Exception e)
{
e.printStackTrace();
}
}
System.out.println("演员表演了"+voice);
//通知观众观看
this.notifyAll();
this.voice = voice;
this.flag = !this.flag;
}
//观众看
public synchronized void watch() {
if(flag)
{
try {
this.wait();
}catch(Exception e)
{
e.printStackTrace();
}
}
System.out.println("观看了"+voice);
//通知演员表演
this.notifyAll();
this.flag = !this.flag;
}
}
运行结果：
27：线程池
package demo4;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
//测试线程池
public class TestPool {
public static void main(String[] args) {
// TODO Auto-generated method stub
//1.创建线程池
ExecutorService service = Executors.newFixedThreadPool(10);
//执行
service.execute(new MyThread());
service.execute(new MyThread());
service.execute(new MyThread());
service.execute(new MyThread());
//关闭连接
service.shutdown();
}
}
class MyThread implements Runnable{
@Override
public void run() {
for(int i=0;i<2;i++)
{
System.out.println(Thread.currentThread().getName()+" "+i);
}
}
}
运行结果：
28总结
package demo4;
import java.util.concurrent.Callable;
import java.util.concurrent.FutureTask;
//回顾总结线程的创建
public class ThreadNew {
public static void main(String[] args) {
// TODO Auto-generated method stub
new MyThread1().start();
new Thread(new MyThread2()).start();
FutureTask<Integer> f = new FutureTask<Integer>(new MyThread3());
new Thread(f).start();
try {
Integer i = f.get();
System.out.println(i);
}catch(Exception e)
{
e.printStackTrace();
}
}
}
//1.继承Thread类
class MyThread1 extends Thread{
@Override
public void run() {
System.out.println("MyThread1");
}
}
//2.实现Runnable接口
class MyThread2 implements Runnable{
@Override
public void run() {
System.out.println("MyThread2");
}
}
//3.实现Callable接口
class MyThread3 implements Callable<Integer>{
@Override
public Integer call() throws Exception{
System.out.println("MyThread3");
return 100;
}
}
运行结果：
