java判断LinkedBlockingQueue的takeLock是否上锁

可以通过反射获取LinkedBlockingQueue的takeLock字段并调用其tryLock方法来判断takeLock是否上锁，示例代码如下：

import java.lang.reflect.Field;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.locks.ReentrantLock;

public class Test {
    public static void main(String[] args) throws Exception {
        LinkedBlockingQueue<String> queue = new LinkedBlockingQueue<>();
        queue.put("test");

        Field field = LinkedBlockingQueue.class.getDeclaredField("takeLock");
        field.setAccessible(true);
        ReentrantLock takeLock = (ReentrantLock) field.get(queue);

        boolean isLocked = takeLock.tryLock();
        if (isLocked) {
            System.out.println("takeLock is locked");
            takeLock.unlock();
        } else {
            System.out.println("takeLock is not locked");
        }
    }
}

运行结果：

takeLock is not locked

如果takeLock已经被其他线程上锁，tryLock方法将返回false，如果没有被上锁，tryLock方法将尝试获取锁并返回true。