マルチスレッドとスレッド同期を実現する Java の古典的な手法

package test;public class MyThread extends Thread{ //构造方法添加线程名称 public MyThread(){} public MyThread(String name) { super(name); } @Override public void run() { for(int i=0;i

package test;public class Demo { public static void main(String[] args) { /* MyThread my1 = new MyThread(); MyThread my2 = new MyThread(); //2,void setName(Stringname) 将此线程的名称更改为等于参数name my1.setName("高铁"); my2.setName("飞机");*/ //3，通过构造方法设置线程名称 //需要自己定义的类中提供此带参构造方法，并通过super访问父类带参构造方法 /*MyThread my1 = new MyThread("高铁"); MyThread my2 = new MyThread("飞机"); my1.start(); my2.start();*/ //4，public static Thread currentThread() 返回对当前正在执行的线程对象的引用（可以返回main()方法中线程） System.out.println(Tread.currentThread().getName()); //main }}

package test;public class Demo { public static void main(String[] args) { ThreadPriority tp1 = new ThreadPriority(); ThreadPriority tp2 = new ThreadPriority(); ThreadPriority tp3 = new ThreadPriority(); tp1.setName("高铁"); tp2.setName("飞机"); tp3.setName("汽车"); //1,public final int getPriority() [praɪˈɔːrəti] 返回此线程的优先级// System.out.println(tp1.getPriority()); //5// System.out.println(tp2.getPriority()); //5// System.out.println(tp3.getPriority()); //5 //2,public final void setPriority(int newPriority) 更改此线程的优先级 System.out.println(Thread.MAX_PRIORITY); //10 System.out.println(Thread.MIN_PRIORITY); //1 System.out.println(Thread.NORM_PRIORITY); //5 //设置正确优先级 tp1.setPriority(5); tp2.setPriority(10); tp3.setPriority(1); tp1.start(); tp2.start(); tp3.start(); }}

package test;public class ThreadSleep extends Thread{ @Override public void run() { for(int i=0;i

package test;public class Demo { public static void main(String[] args) { ThreadSleep ts1 = new ThreadSleep(); ThreadSleep ts2 = new ThreadSleep(); ThreadSleep ts3 = new ThreadSleep(); ts1.setName("曹操"); ts2.setName("刘备"); ts3.setName("孙权"); ts1.start(); ts2.start(); ts3.start();// 曹操:0// 孙权:0// 刘备:0// 孙权:1// 曹操:1// 刘备:1// ... }}

package test;public class Demo { public static void main(String[] args) { ThreadJoin tj1 = new ThreadJoin(); ThreadJoin tj2 = new ThreadJoin(); ThreadJoin tj3 = new ThreadJoin(); tj1.setName("康熙"); tj2.setName("四阿哥"); tj3.setName("八阿哥"); tj1.start(); //2,void join() 等待这个线程死亡 try { tj1.join(); } catch (InterruptedException e) { e.printStackTrace(); } tj2.start(); tj3.start();// 康熙:0// 康熙:1// 康熙:2// 四阿哥:0// 四阿哥:1// 八阿哥:0// 八阿哥:1// 八阿哥:2// 四阿哥:2// ... }}

package test;public class Demo { public static void main(String[] args) { ThreadJoin tj1 = new ThreadJoin(); ThreadJoin tj2 = new ThreadJoin(); ThreadJoin tj3 = new ThreadJoin(); tj2.setName("关羽"); tj3.setName("张飞"); //设置主线程为刘备 Thread.currentThread().setName("刘备"); //3,void setDaemon(boolean on) 将此线程标记为守护线程，当运行的线程都是守护线程时，Java虚拟机将退出 tj1.setDaemon(true); tj2.setDaemon(true); tj1.start(); tj2.start(); for(int i=0;i
1.7 线程生命周期
1.8 数据安全问题之案例：买票

synchronized(任意对象) { 多条语句操作共享数据的代码}

package test;//1,定义一个类SellTicket实现Runnable接口，里面定义一个成员变量: private int tickets= 100;public class SellTicket implements Runnable{ private int tickets = 100; private Object obj = new Object(); //2,在ellTicket类中重写run0方法实现卖票， 代码步骤如下 @Override public void run() { while(true) { //tickes=100 //t1,t2,t3 //假设t1抢到CPU执行器 synchronized (obj){ //t1进来后把代码锁起来了 if (tickets > 0) { try { Thread.sleep(100); //t1休息100毫秒 } catch (InterruptedException e) { e.printStackTrace(); } //窗口1正在出售第100张票 System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票"); tickets--; //tickets=99 } //t1出来了，锁就被释放了 } } }}

package test;public class SellTicketDemo { public static void main(String[] args) { //创建SellTicket类的对象 SellTicket st = new SellTicket(); //创建三个Thread类的对象,把SellTicket对象作为构造方法的参数，并给出对应的窗口名称 Thread t1 = new Thread(st,"窗口1"); Thread t2 = new Thread(st,"窗口2"); Thread t3 = new Thread(st,"窗口3"); //启动线程 t1.start(); t2.start(); t3.start(); }}

package test;public class SellTicket implements Runnable{//1非静态 private int tickets = 100; private static int tickets = 100; private Object obj = new Object(); private int x = 0; @Override public void run() { while(true) { if(x%2==0) {//1非静态 synchronized (this) { synchronized (SellTicket.class) { if (tickets > 0) { try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票"); tickets--; //tickets=99 } } } else {// synchronized (obj) {// if (tickets > 0) {// try {// Thread.sleep(100);// } catch (InterruptedException e) {// e.printStackTrace();// }// System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");// tickets--; //tickets=99// }// } sellTicket(); } x++; } }//1非静态// private synchronized void sellTicket() {// if (tickets > 0) {// try {// Thread.sleep(100);// } catch (InterruptedException e) {// e.printStackTrace();// }// System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票");// tickets--; //tickets=99// }// } private static synchronized void sellTicket() { if (tickets > 0) { try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票"); tickets--; //tickets=99 } }}

package test;import java.util.ArrayList;import java.util.Collection;import java.util.Collections;public class Demo { public static void main(String[] args) { //static  List snchronizedList(List list)：返回由指定列表支持的同步（线程安全）的列表 Collection list = Collections.synchronizedList(new ArrayList()); /*源码都是返回Synchronized public static  List synchronizedList(List list) { return (list instanceof RandomAccess ? new Collections.SynchronizedRandomAccessList(list) : new Collections.SynchronizedList(list)); }*/ }}

package test;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;public class SellTicket implements Runnable{ private static int tickets = 100; private Lock lock = new ReentrantLock(); @Override public void run() { while(true) { try { lock.lock(); if (tickets > 0) { try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println(Thread.currentThread().getName() + "正在出售第" + tickets + "张票"); tickets--; } }finally { lock.unlock(); } } }}

package test;//1：定义奶箱类public class Box { //定义一个成员变量，表示第x瓶奶 private int milk; //定义一个成员变量表示奶箱的状态 private boolean state = false; //提供存储牛奶和获取牛奶的操作 public synchronized void put(int milk) { //如果有牛奶等待消费 if(state) { try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } //如果没有牛奶，就生产牛奶 this.milk = milk; System.out.println("送奶工将第" + this.milk + "瓶奶放入奶箱"); //生产完毕后，修改奶箱状态 state = true; //唤醒其他等待线程 notifyAll(); } public synchronized void get() { //如果没有牛奶，就等到生产 if(!state) { try { wait(); } catch (InterruptedException e) { e.printStackTrace(); } } //如果有牛奶，就消费牛奶 System.out.println("用户拿到第" + this.milk + "瓶奶"); //消费完毕后,修改奶箱状态 state = false; //唤醒其他等待线程 notifyAll(); }}

package test;//2:生产者类(Producer):实现Runnable接口public class Producer implements Runnable { private Box b; public Producer(Box b) { this.b = b; } //重写run()方法，调用存储牛奶的操作 @Override public void run() { for (int i = 1; i

package test;//3:消费者类(Customer);实现Runnable接口public class Customer implements Runnable{ private Box b; public Customer(Box b) { this.b = b; } //重写run()方法，调用获取牛奶的操作 @Override public void run() { while(true) { b.get(); } }}

package test;public class BoxDemo { public static void main(String[] args) { //创建奶箱对象，这是共享数据区域 Box b = new Box(); //创建生产者对象，把奶箱对象作为构造方法参数传递。因为在这个类中要谓用存储牛奶的操作 Producer p = new Producer(b); //创建消费者对象，把奶箱对象作为构造方法参数传递，因为在这个类中要调用获取牛奶的操作 Customer c =new Customer(b); //创建2个线程对象，分别把生产者对象和消费者对象作为构造方法参数传递 Thread t1 = new Thread(p); Thread t2 = new Thread(c); //启动线程 t1.start(); t2.start();// 送奶工将第1瓶奶放入奶箱// 用户拿到第1瓶奶// 送奶工将第2瓶奶放入奶箱// 用户拿到第2瓶奶// 送奶工将第3瓶奶放入奶箱// 用户拿到第3瓶奶// 送奶工将第4瓶奶放入奶箱// 用户拿到第4瓶奶// 送奶工将第5瓶奶放入奶箱// 用户拿到第5瓶奶 }}