ReentrantLock显示锁

public class AttemptLocking {

    /*
     * public AttemptLocking() {
     *
     * System.out.println("构造器初始化...");
     * }
     *
     * {
     * System.out.println("init ...");
     * }
     *
     * static {
     * System.out.println("static init ");
     * }
     */
    private ReentrantLock reentrantLock = new ReentrantLock();

    public void unTimed() {

        boolean captured = reentrantLock.tryLock();

        try {
            System.out.println("try lock:" + captured);
        } finally {
            // TODO: handle finally clause
            if (captured) {
                reentrantLock.unlock();
            }
        }
    }

    public void timed() {
        boolean captured = false;

        try {
            try {
                captured = reentrantLock.tryLock(2, TimeUnit.SECONDS);
                System.out.println("tryLock 2 Seconds " + captured);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        } finally {
            // TODO: handle finally clause
            if (captured) {
                reentrantLock.unlock();
            }
        }

    }

    public static void main(String[] args) {
        final AttemptLocking attemptLocking = new AttemptLocking();
        attemptLocking.unTimed();
        attemptLocking.timed();
        new Thread() {

            {
                setDaemon(true);

            }

            @Override
            public void run() {

                attemptLocking.reentrantLock.lock();

                System.out.println("acquired");
            };

        }.start();
        Thread.yield();// give the 2nd task a chance只是给另一个线程一个机会，并不保证另一个线程一定能得到资源
        attemptLocking.unTimed();
        attemptLocking.timed();
    }

}
output:

p.p1 { margin: 0; font: 11px Monaco }

try lock:true

tryLock 2 Seconds true

acquired

try lock:false

tryLock 2 Seconds false

或