从文件中读取最后一个字节并截断为大小 [英] Read last byte from file and truncate to size
问题描述
我知道我可以读取整个事情,并把它写回去减去最后一个字符,但必须有一种方法来获得一个特定的字节,是不是? 解决方案
您可以使用RandomAccessFile类来查找文件末尾,读取它,然后使用 setLength()
更新:以下是一些代码:
File target = new File(/ path / to / file);
RandomAccessFile file = new RandomAccessFile(target,rwd);
file.seek(target.length() - 1); //设置指针到文件的末尾
char c = file.readChar();
if(c =='|')//将管道字符更改为你的哨兵字符是
{
file.setLength(target.length() - 1); //去掉最后一个_byte_,而不是最后一个字符
}
注意:没有测试这个代码,没有错误处理等。
如果这个文件是非8位字符集,那么这个目标。 length() - 1
将需要调整。
I have a huge set of files, to all of which there is (should be) a sentinel character (1 byte) appended to the end of file. How can I read the very last byte (to ensure it is the character) and truncate it to size (ie: remove the character)?
I know I could read the whole thing, and write it all back minus the last character, but there's got to be a way to get to a specific byte, isn't there?
You can use the RandomAccessFile class to seek to the end of the file, read it, and then truncate the file using setLength()
.
Update: Here's some code:
File target = new File("/path/to/file");
RandomAccessFile file = new RandomAccessFile(target,"rwd");
file.seek(target.length()-1); // Set the pointer to the end of the file
char c = file.readChar();
if(c == '|') // Change the pipe character to whatever your sentinel character is
{
file.setLength(target.length()-1); // Strip off the last _byte_, not the last character
}
Note: I haven't tested this code, no error handling, etc.
If the file is in any non-8-bit character set, the target.length()-1
will need to be adjusted.
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