如何使用Java的FileLock类实现文件锁定的功能，以确保同一时间只有一个线程可以访问文件？

import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.io.IOException;

public class FileLockExample {
    public static void main(String[] args) {
        RandomAccessFile file = null;
        FileChannel channel = null;
        FileLock lock = null;

        try {
            // 打开文件
            file = new RandomAccessFile("example.txt", "rw");
            channel = file.getChannel();

            // 获取文件锁，阻塞式锁定
            lock = channel.lock();

            System.out.println("File locked successfully. Performing file operations...");

            // 在这里执行对文件的读取或写入操作
            // 例如，写入文件内容
            file.write("Hello, world!".getBytes());

            // 模拟长时间操作
            Thread.sleep(2000);

        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        } finally {
            try {
                // 释放锁
                if (lock != null) {
                    lock.release();
                    System.out.println("File lock released.");
                }

                // 关闭文件通道
                if (channel != null) {
                    channel.close();
                }
                if (file != null) {
                    file.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

import java.io.RandomAccessFile;
import java.nio.channels.FileChannel;
import java.nio.channels.FileLock;
import java.io.IOException;

public class TryLockExample {
    public static void main(String[] args) {
        RandomAccessFile file = null;
        FileChannel channel = null;
        FileLock lock = null;

        try {
            // 打开文件
            file = new RandomAccessFile("example.txt", "rw");
            channel = file.getChannel();

            // 非阻塞的尝试获取文件锁
            lock = channel.tryLock();

            if (lock != null) {
                System.out.println("File locked successfully.");

                // 在这里执行文件操作
                file.write("Hello, non-blocking world!".getBytes());
            } else {
                System.out.println("Could not acquire file lock.");
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (lock != null) {
                    lock.release();
                    System.out.println("File lock released.");
                }
                if (channel != null) {
                    channel.close();
                }
                if (file != null) {
                    file.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}