Java.io.File.length()返回0 [英] Java.io.File.length() returns 0

问题描述

我正在为ftp文件传输做一个applet，我需要知道本地文件的大小(用于下载恢复).问题是File.length()返回0.

I'm doing a applet for ftp file transfers and I need to know the size of a local file (for download resumes). The problem is the File.length() returns 0.

该文件存在(已通过File.exists()检查)，并且具有超过0个字节(至少在Windows中).

The file exists (checked with File.exists()), and has more than 0 bytes (in Windows at least).

我不知道还有什么地方可以找出为什么length()返回0.

I don't know where more to look to find out why length() is returning 0.

这是代码和结果的一部分.

Here is part of the code and the result.

long fileOffset = 0;

if(localfile.exists()){
    fileOffset = localfile.length();
    System.out.println("The file " + localfile.getAbsolutePath() + " has " + localfile.length() +" in size");
    System.out.println("Resume at: " + fileOffset);
    outputStream.skip(fileOffset);
    ftp.setRestartOffset(fileOffset);
    count = fileOffset;
}

控制台中的结果是:

The file D:\test\About Downloads.pdf has 0 in size
Resume at: 0

谢谢

推荐答案

变量"outputStream"的存在表明，此时，也许您已经打开了要写入的文件，并且在此过程中，您已经截断它.在实际打开文件之前尝试计算大小?

The existence of the variable "outputStream" suggests that at this point, perhaps you've already opened the file for writing, and in the process, you've truncated it. Try computing the size before actually opening the file?

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