importjava.text.ParseException;importjava.text.SimpleDateFormat;importjava.util.Date;importjava.util.concurrent.ExecutorService;importjava.util.concurrent.Executors;publicclassThreadLockTest1 {staticThreadLocal<SimpleDateFormat> t1 =newThreadLocal<>();publicstaticclassParseDateimplementsRunnable {inti = 0;publi...
final Thread current = Thread.currentThread(); int c = getState(); if (c == 0) {//关键点1 if (compareAndSetState(0, acquires)) { setExclusiveOwnerThread(current); return true; } } else if (current == getExclusiveOwnerThread()) { int nextc = c + acquires;//关键点2 if (next...
Lock lock = new ReentrantLock(); @Override public void run() { try { lock.lock(); if (ticket > 0) { ticket--; System.out.println(Thread.currentThread().getName() + "抢到了第" + ticket + "张票"); Thread.sleep(10); } } catch (InterruptedException e) { e.printStackTrace(); }...
/* Write Lock 写锁的源码 */ protected final boolean tryAcquire(int acquires) { Thread current = Thread.currentThread(); int c = getState(); // 取到当前锁的个数 int w = exclusiveCount(c); // 取写锁的个数w if (c != 0) { // 如果已经有线程持有了锁(c!=0) // (Note: if c ...
1)Lock是一个接口,而synchronized是Java中的关键字,synchronized是内置的语言实现; 2)synchronized在发生异常时,会自动释放线程占有的锁,因此不会导致死锁现象发生;而Lock在发生异常时,如果没有主动通过unLock()去释放锁,则很可能造成死锁现象,因此使用Lock时需要在finally块中释放锁; ...
locks.Lock;import java.util.concurrent.locks.ReentrantLock;public class ReentrantLock01 { public static void main(String[] args) { ServiceA serviceA = new ServiceA(); ThreadA threadA1 = new ThreadA(serviceA); ThreadA threadA2 = new ThreadA(serviceA); ThreadA threadA3 = new ThreadA(...
// 此方法未获得锁会立即返回,不会使当前线程休眠,lock()会使线程休眠 try { // 相当于获得锁的最大延迟等待时间 if (myLock.tryLock(5000, TimeUnit.MILLISECONDS)) { try { log.info("当前线程获得锁"); Thread.sleep(500); } catch (Exception e) { ...
()+"LockB 开始执行");while(true){synchronized(LockTest.obj2){System.out.println(newDate().toString()+"LockB 锁住 obj2");Thread.sleep(3000);//此处等待是给A能锁住机会synchronized(LockTest.obj1){System.out.println(newDate().toString()+"LockB 锁住 obj1");Thread.sleep(60*1000);//为...
// 餐厅的座位，用Lock表示 privatefinal Lock seat = new ReentrantLock(); // 客户进入餐厅并坐下 publicvoidenterAndSit(){ // 客户尝试获取座位锁 seat.lock(); try { // 客户已经坐下，这里可以执行就餐的相关操作 System.out.println(Thread.currentThread().getName() + " 已进入餐厅...
1)Lock不是Java语言内置的,synchronized是Java语言的关键字,因此是内置特性。Lock是一个类,通过这个类可以实现同步访问; 2)Lock和synchronized有一点非常大的不同,采用synchronized不需要用户去手动释放锁,当synchronized方法或者synchronized代码块执行完之后,系统会自动让线程释放对锁的占用;而Lock则必须要用户去手动释放锁...