概述

tryLock()方法是有返回值的，它表示用來嘗試獲取鎖，如果獲取成功，則返回true，如果獲取失敗（即鎖已被其他線程獲取），則返回false，這個方法無論如何都會立即返回。在拿不到鎖時不會一直在那等待。

代碼

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

運行結果

Thread-0獲取到鎖！
Thread-0:0
Thread-0:1
Thread-0:2
Thread-0:3
Thread-0:4
Thread-1獲取不到鎖！