从文件中读取不可打印字符

Question

I'm trying to read a character as an integer from a file and I receive an exception of NumberFormatException:

Java.lang.NumberFormatException: For input string: "4 " java.lang.NumberFormatException.forInputString(NumberFormatException.java:48) at java.lang.Integer.parseInt(Integer.java:458) at java.lang.Integer.valueOf(Integer.java:554) at Main.main(Main.java:9)

I'm pretty sure it's from the file, as it can be reproduced only when I copy the text to the file, when typed manually, it parses properly. My question is: how can I avoid this exception and make that "4" to be parsed to the variable? The line where I parse it is: int m = Integer.valueOf(inputFile.readLine());

Answer 1

It seems that there are some special characters in your input, to avoid this problem you can use :

int m = Integer.valueOf(inputFile.readLine().replaceAll("[^\\d]+", ""));

Which mean replace any non digit with empty