Java ReentrantReadWriteLocks - 如何在读锁中安全地获取写锁

java
import java.util.concurrent.locks.ReentrantReadWriteLock;
public class ReadWriteLockExample {
    private ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
    private String resource = "Shared Resource";
    public void readResource() {
        lock.readLock().lock();
        try {
            System.out.println("Reading resource: " + resource);
        } finally {
            lock.readLock().unlock();
        }
    }
    public void writeResource() {
        if (lock.readLock().tryLock()) {
            try {
                lock.writeLock().lock();
                System.out.println("Writing resource");
                resource = "Updated Resource";
            } finally {
                lock.writeLock().unlock();
                lock.readLock().unlock();
            }
        } else {
            System.out.println("Cannot obtain write lock");
            // Handle alternative action
        }
    }
    public static void main(String[] args) {
        ReadWriteLockExample example = new ReadWriteLockExample();
        example.readResource();
        example.writeResource();
    }
}