Java 如何检查文件是否已打开

我所需要的帮助是测试文件是否打开

以下是我所拥有的：

public static void main(String[] args) {

    //Prompt user to input file name
    SimpleIO.prompt("Enter File name: ");
    String fileName = SimpleIO.readLine();

    //Create file object 
    File file = new File (fileName);

    //Check to see if file is opened 

    if (!file.exists()){
        System.out.println("The file you entered either do not exist or the name is spelled wrong.\nProgram is now being terminated.\nGoodbye!");}
}

如果这

//Create file object 
File file = new File (fileName);

如果不生成异常，则文件访问正确。但是，如果您需要检查文件是否已写入或以其他方式访问，则需要检查文件是否已锁定

File file = new File(fileName);
FileChannel channel = new RandomAccessFile(file, "rw").getChannel();

FileLock lock = channel.lock();
try {
    lock = channel.tryLock();
    System.out.print("file is not locked");
} catch (OverlappingFileLockException e) {
    System.out.print("file is locked");
} finally {
    lock.release();
}

如果这

//Create file object 
File file = new File (fileName);

如果不生成异常，则文件访问正确。但是，如果您需要检查文件是否已写入或以其他方式访问，则需要检查文件是否已锁定

File file = new File(fileName);
FileChannel channel = new RandomAccessFile(file, "rw").getChannel();

FileLock lock = channel.lock();
try {
    lock = channel.tryLock();
    System.out.print("file is not locked");
} catch (OverlappingFileLockException e) {
    System.out.print("file is locked");
} finally {
    lock.release();
}

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