将二进制文件读入字符串 [英] Reading a binary file into a string
问题描述
一定是显而易见的，但我无法弄清楚。
我花了差不多一整天的时间。
我很乐意给可以照亮我的人买啤酒。
It must be obvious, but I can't figure it out. I spent almost a whole day for this. I'll gladly buy a beer to someone who can lighten me.
File file = new File(filePath);
byte[] bytes = new byte[(int)file.length()];
DataInputStream dataInputStream = new DataInputStream(new BufferedInputStream(new FileInputStream(filePath)));
dataInputStream.readFully(bytes);
dataInputStream.close();
return new String(bytes);
这是我的代码。
我看到字节数组大小不正常，但我无法找出合适的大小。
除此之外，内容也不正确。
似乎只有文本字符没问题。
This is my code. I see that the byte array size is not OK, but I can't figure out the right size. Besides that the contents are not also incorrect. It seems that only the text characters are OK.
似乎从二进制文件中获取数据真的很痛苦，我真的很沮丧。
It seems get out the data from a binary file is a real pain, I'm really depressed.
还有一件事：文件内容不是文本，可以是图片，视频或pdf。
One more thing: the file contents are not text, it can be anything like a picture, video, or pdf.
推荐答案
如果您正在阅读二进制文件，则不会尝试将其视为编码文本。将它转换为这样的字符串是不合适的 - 你应该把它保存为字节数组。如果确实需要它作为文本，则应使用base64或hex来表示二进制数据 - 其他方法可能会丢失数据。
If you're reading a binary file you should not try to treat it as if it were encoded text. It's inappropriate to convert it to a string like this - you should keep it as a byte array. If you really need it as text, you should use base64 or hex to represent the binary data - other approaches are likely to lose data.
如果 readFully 在没有异常的情况下返回，则表明它读取的数据与您请求的数据一样多，应该是整个文件。你已经设法从二进制文件中轻松获取数据（虽然 close（）调用应该在finally块中） - 它只是将它转换为文本，这是一个坏主意。
If readFully returned without an exception, that shows it's read as much data as you requested, which should be the whole file. You've managed to get the data from a binary file fairly easily (although the close() call should be in a finally block) - it's only converting it to text which is a bad idea.
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