java计数器count计数器

public class SimpleCounter {
    private int count = 0;

    public void increment() {
        count++;
    }

    public int getCount() {
        return count;
    }
}

import java.util.concurrent.atomic.AtomicInteger;

public class ConcurrentCounter {
    private AtomicInteger count = new AtomicInteger(0);

    public void increment() {
        count.incrementAndGet();
    }

    public int getCount() {
        return count.get();
    }
}

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class SynchronizedCounter {
    private int count = 0;
    private final Lock lock = new ReentrantLock();

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

    public int getCount() {
        lock.lock();
        try {
            return count;
        } finally {
            lock.unlock();
        }
    }
}

public class LongCounter {
    private long count = 0;

    public void increment() {
        count++;
    }

    public long getCount() {
        return count;
    }
}