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");
						}
					}
				}
			}