java有哪几种锁实现用代码示例写出来

在Java中，有以下几种锁的实现：

synchronized关键字：

public class SynchronizedExample {
    private int counter = 0;

    public synchronized void increment() {
        counter++;
    }
}

ReentrantLock类：

import java.util.concurrent.locks.ReentrantLock;

public class ReentrantLockExample {
    private int counter = 0;
    private ReentrantLock lock = new ReentrantLock();

    public void increment() {
        lock.lock();
        try {
            counter++;
        } finally {
            lock.unlock();
        }
    }
}

ReadWriteLock接口的实现类ReentrantReadWriteLock：

import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

public class ReadWriteLockExample {
    private int counter = 0;
    private ReadWriteLock lock = new ReentrantReadWriteLock();

    public void increment() {
        lock.writeLock().lock();
        try {
            counter++;
        } finally {
            lock.writeLock().unlock();
        }
    }
}

StampedLock类：

import java.util.concurrent.locks.StampedLock;

public class StampedLockExample {
    private int counter = 0;
    private StampedLock lock = new StampedLock();

    public void increment() {
        long stamp = lock.writeLock();
        try {
            counter++;
        } finally {
            lock.unlockWrite(stamp);
        }
    }
}
``