获取文本文件中行的字节偏移量？ [英] Getting byte offset of line in a text file?

问题描述

我有一个文本文件，如

one
two
three
four
five

我需要获取文件中每一行的偏移量。我如何用Java做到这一点？

I need to get the offset of each line in the file. How do I do this in Java?

我搜索了一些I / O库（如BufferedReader和RandomAccessFile），但我找不到满意的答案对此。

I have searched through some of the I/O libraries(like BufferedReader and RandomAccessFile) but I'm unable to find a satisfactory answer to this.

任何人都可以建议如何处理这个问题吗？

Can anyone suggest how to deal with this?

推荐答案

另一种方法是计算每一行的字节数

Another approach would be to count the bytes of each line line this

        BufferedReader br = null;   
    try {

        String line;
        // in my test each character was one byte
        ArrayList<Integer> byteoffset = new ArrayList<Integer>();

        br = new BufferedReader(new FileReader("numbers.txt"));
        Integer l = 0;
        while ((line = br.readLine()) != null) {
            System.out.println(line);
            Integer num_bytes = line.getBytes().length;
            System.out.println(num_bytes);
            byteoffset.add( l==0 ? num_bytes : byteoffset.get(l-1)+num_bytes );
            l++;
        }

    } catch ( Exception e) {

    }

在这个例子中，您还需要将换行符\ n的大小添加到每行的大小

in this example you would also need to add the size of the newline character \n to size of each line

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