概述

tryLock()方法是有返回值的，它表示用来尝试获取锁，如果获取成功，则返回true，如果获取失败（即锁已被其他线程获取），则返回false，这个方法无论如何都会立即返回。在拿不到锁时不会一直在那等待。

代码

@Testpublic void testTryLock() {Lock lock = new ReentrantLock();new Thread() {@Overridepublic void run() {String tName = Thread.currentThread().getName();if (lock.tryLock()) {System.out.println(tName + "获取到锁！");} else {System.out.println(tName + "获取不到锁！");return;}try {for (int i = 0; i < 5; i++) {System.out.println(tName + ":" + i);}Thread.sleep(5000);} catch (Exception e) {System.out.println(tName + "出错了！！！");} finally {System.out.println(tName + "释放锁！！");lock.unlock();}}}.start();new Thread() {@Overridepublic void run() {String tName = Thread.currentThread().getName();if (lock.tryLock()) {System.out.println(tName + "获取到锁！");} else {System.out.println(tName + "获取不到锁！");return;}try {for (int i = 0; i < 5; i++) {System.out.println(tName + ":" + i);}} catch (Exception e) {System.out.println(tName + "出错了！！！");} finally {System.out.println(tName + "释放锁！！");lock.unlock();}}}.start();}

运行结果

Thread-0获取到锁！
Thread-0:0
Thread-0:1
Thread-0:2
Thread-0:3
Thread-0:4
Thread-1获取不到锁！