如何检查文件是否被打开

Question

我需要帮助的只是测试文件是否已打开。

这是我所拥有的：

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!");}
}

Answer 1

如果这

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

不产生异常，则文件被正确访问。但是，如果您需要检查文件是否正在写入或是否已以其他方式被访问，则需要检查它是否已锁定。

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();
}