多线程(线程安全问题)学习笔记

多线程并发操作同一数据时, 就有可能出现线程安全问题
* 使用同步技术可以解决这种问题, 把操作数据的代码进行同步, 不要多个线程一起操作

            public class Demo2_Synchronized {

                /**
                 * @param args
                 * 需求:铁路售票,一共100张,通过四个窗口卖完.
                 */
                public static void main(String[] args) {
                    TicketsSeller t1 = new TicketsSeller();
                    TicketsSeller t2 = new TicketsSeller();
                    TicketsSeller t3 = new TicketsSeller();
                    TicketsSeller t4 = new TicketsSeller();

                    t1.setName("窗口1");
                    t2.setName("窗口2");
                    t3.setName("窗口3");
                    t4.setName("窗口4");
                    t1.start();
                    t2.start();
                    t3.start();
                    t4.start();
                }

            }

            class TicketsSeller extends Thread {
                private static int tickets = 100;
                static Object obj = new Object();
                public TicketsSeller() {
                    super();

                }
                public TicketsSeller(String name) {
                    super(name);
                }
                public void run() {
                    while(true) {
                        synchronized(obj) {
                            if(tickets <= 0) 
                                break;
                            try {
                                Thread.sleep(10);//线程1睡,线程2睡,线程3睡,线程4睡
                            } catch (InterruptedException e) {

                                e.printStackTrace();
                            }
                            System.out.println(getName() + "...这是第" + tickets-- + "号票");
                        }
                    }
                }
            }