Android：在文件中定位（类似于C ++中的fseek）？

Question

I'm trying to read some data from html file that I opened from internet using httpClient. I'm using readLine() function in loop for reading.

The lines I want to read start at 500th row. Is there a faster way to position at file?

Problem is that reading all that unnecessary data takes too long (almost 10 seconds to finish loading all).

Answer 1

在InputStream中，您可以使用skip(long n)许多字符

Answer 2

You'll have to cross 499 line terminating characters to get to the 500th line (as getline() gets a line terminated by '\\n' , '\\r' or "\\r\\n" ).

The definition of a line is the basic problem. As a line is terminated using the above terminators(standard definition in most languages), for any algorithm that skips n lines, the algorithm will need to discover n line terminators. This means that the input stream will need to be examined byte/char by byte/char to discover the terminators, which leads to the conclusion that while you can only skip characters, but you cannot skip lines . Here skipping means that data need not be examined (either in your code or in the library code), for eg. a random access file type seek() or a File Stream skip(n) operation.

Thus, you might want to rethink your data structures, or the need to skip lines.