How can I read text from a file in Java with streams of size I choose?

Question

So I can read a text file with Java like this just fine:

File file = new File("C:/text.txt");
Scanner scanner = new Scanner(file,"utf-8");
while (scanner.hasNext()) {
    scanner.nextLine();
    // rest of the code...

I am not 100% sure but I believe this loads the whole file and then reads the text line by line.

Suppose you have a very large text file where one line might be way too long.

How can I read the text from the file, say like 50 characters per time? What I want is in every iteration I should get 50 characters, not more.

You would use a BufferedReader in that case and specify the bytes to be read in each iteration. — W.K.S, Apr 21 '14 at 06:29
@W.K.S Will this avoid loading the whole file in the memory as well? — Koray Tugay, Apr 21 '14 at 06:29
Please look this one http://stackoverflow.com/questions/2039229/using-java-util-scanner-to-read-a-file-byte-by-byte — Prabhakaran Ramaswamy, Apr 21 '14 at 06:30
I believe neither BufferedReader nor Scanner load the entire file into memory. — W.K.S, Apr 21 '14 at 06:31
You are mistaken. It reads the file line by line and throws each line away. It does not load the entire file into memory. — user207421, Apr 25 '14 at 00:37

score 3 · Accepted Answer · edited May 23 '17 at 12:04

A simple text scanner which can parse primitive types and strings using regular expressions.

A Scanner breaks its input into tokens using a delimiter pattern, which by default matches whitespace. The resulting tokens may then be converted into values of different types using the various next methods.

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html

here is answer: Faster way to read file

How can I read text from a file in Java with streams of size I choose?

1 Answers1