ReentrantLock用法

ReentrantLock实现同步锁

public class MyTask {

    private Lock lock = new ReentrantLock();
    
    public void execute() {
        lock.lock();
        
        for (int i = 0 ; i < 3 ; i++) {
            System.out.println(Thread.currentThread().getName() + " " + i);
        }
        lock.unlock();
    }
}

public class MyThread extends Thread {

    private MyTask myTask;
    
    public MyThread(MyTask myTask) {
        this.myTask = myTask;
    }
    
    @Override
    public void run() {
        myTask.execute();
    }
}

public class MyTest {

    public static void main(String[] args) {
        MyTask myTask = new MyTask();
        MyThread mt1 = new MyThread(myTask);
        mt1.setName("mt1");
        MyThread mt2 = new MyThread(myTask);
        mt2.setName("mt2");
        mt1.start();
        mt2.start();
    }
}

结果：

mt1 0
mt1 1
mt1 2
mt2 0
mt2 1
mt2 2

Condition等待/唤醒

public class MyTask {

    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();
    
    public void executeWait() {
        try {
            lock.lock();
            System.out.println(Thread.currentThread().getName() + " await start");
            condition.await();
            System.out.println(Thread.currentThread().getName() + " await end");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    
    public void executeSignal() {
        lock.lock();
        System.out.println(Thread.currentThread().getName() + " signal start");
        condition.signal();
        System.out.println(Thread.currentThread().getName() + " signal end");
        lock.unlock();
    }
}

public class MyTest {

    public static void main(String[] args) {
        final MyTask myTask = new MyTask();
        Thread t1 = new Thread(new Runnable() {

            @Override
            public void run() {
                myTask.executeWait();
            }
        });
        t1.setName("t1");
        
        Thread t2 = new Thread(new Runnable() {

            @Override
            public void run() {
                myTask.executeSignal();
            }
        });
        t2.setName("t2");
        
        t1.start();
        t2.start();
    }
}

结果：

t1 await start
t2 signal start
t2 signal end
t1 await end

多个Condition实现部分通知

public class MyTask {

    private Lock lock = new ReentrantLock();
    private Condition condition1 = lock.newCondition();
    private Condition condition2 = lock.newCondition();
    
    public void executeCondition1() {
        try {
            lock.lock();
            System.out.println(Thread.currentThread().getName() + " executeCondition1 start");
            condition1.await();
            System.out.println(Thread.currentThread().getName() + " executeCondition1 end");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    
    public void executeCondition2() {
        try {
            lock.lock();
            System.out.println(Thread.currentThread().getName() + " executeCondition2 start");
            condition2.await();
            System.out.println(Thread.currentThread().getName() + " executeCondition2 end");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            lock.unlock();
        }
    }
    
    public void executeSignal1() {
        lock.lock();
        System.out.println(Thread.currentThread().getName() + " executeSignal1 start");
        condition1.signalAll();
        System.out.println(Thread.currentThread().getName() + " executeSignal1 end");
        lock.unlock();
    }
    
    public void executeSignal2() {
        lock.lock();
        System.out.println(Thread.currentThread().getName() + " executeSignal2 start");
        condition2.signalAll();
        System.out.println(Thread.currentThread().getName() + " executeSignal2 end");
        lock.unlock();
    }
}

public class MyTest {

    public static void main(String[] args) {
        final MyTask myTask = new MyTask();
        Thread t1 = new Thread(new Runnable() {

            @Override
            public void run() {
                myTask.executeCondition1();
            }
        });
        t1.setName("t1");
        
        Thread t2 = new Thread(new Runnable() {

            @Override
            public void run() {
                myTask.executeCondition2();
            }
        });
        t2.setName("t2");
        
        t1.start();
        t2.start();
        
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        
        myTask.executeSignal1();
    }
}

结果：

1.png