从文件Java中读取错误的字符

Question

I am reading characters from file by skipping 2 times

     fis = new FileInputStream("C:/data/25130.in ");
     fis.skip(24305);//This position contains _(UnderScore)
     l=fis.read();
     fis.skip(24312);//This position also contains _(Underscore)
     i = fis.read();
     ch= (char)l;
     c = (char)i;
     System.out.print("Ch: "+ch);//Returns Underscore
     System.out.print("C: "+c); // Returns 9 instead of UnderScore

If i delete the fist skip like the following

     fis = new FileInputStream("C:/data/25130.in ");         
     fis.skip(24312);//This position also contains _(underscore)
     i = fis.read();
     c = (char)i;
     System.out.print("C: "+c); // Now it returns Underscore

I intend to read 2 characters at 2 positions..Where was the problem

Answer 1

fis.skip(24312) skips that many characters (it reads 24312 bytes and throws them away....)

What you want to do is "position" the input stream, and throw away only (24312 - 24305) bytes, or fis.skip(7)

EDIT: hmmm, lutzh is right, you want to fis.skip(6) but....

what you really want to do is use a RandomAccessFile and use the seek(position) method...

Answer 2

I think FileInputStream.skip does not go to the given position, it skips the given number of bytes. So after your second skip you will end up at 48617, plus one more that you actually read.

Try 6 as parameter for your second skip.