public static void main(String[] args) throws FileNotFoundException {
Scanner sc = new Scanner(new FileReader(args[1]));
String co = sc.next();
coup = Integer.parseInt(co);
I get a FileNotFoundException when I try to pass an int into the second argument in command line. This is only part of the code, a text file is passed as args[0]. However, I can't figure out how to pass a simple integer, only text files.
public static void main(String[] args) throws Exception
{
Scanner scan = new Scanner(new FileReader(args[0]));
int integerFromCM = Integer.parseInt(args[1]);
}
You state that a text file is the first argument (args[0]) so assign that in the scanner and when grabbing the integer all you need to do is send args[1] into Integer.parseInt method. You are getting the exception because you are assigning a FileReader object with the file name of the integer passed in.
You can't pass an int, but you can parse one:
public static void main(String[] args) {
String filename = args[0];
int i = Integer.parseInt(args[1]);
// ...
}
If you are getting a FileNotFoundException, one easy way to debug it is:
File file = new File(filename);
System.out.println(file.getAbsolutePath());
and it will be obvious where the problem lies, which is almost always the current directory of the application is not what you think it is.
Reviewing your code it reads as follows:
It is clearly sequenced to require a file from the first argument and that looks like it is intended.
Create a file called number.txt:
42
NumberPrinter.java:
import java.io.Scanner;
import java.io.FileReader;
public final class NumberPrinter {
public static void main(String[] args) throws Exception {
Scanner scanner = new Scanner(new FileReader(args[1]));
String numberInFile = scanner.next();
int number = Integer.parseInt(numberInFile);
System.out.println(number);
}
}
Run as follows:
java NumberPrinter number.txt
And it will print:
42
Alternatively if you intend to parse an int directly from the command line parameters try:
public final class NumberPrinterDirect {
public static void main(String[] args) throws Exception {
int number = Integer.parseInt(args[0]);
System.out.println(number);
}
}
NumberOrFilenameAwkward.java:
import java.io.Scanner;
import java.io.FileReader;
public final class NumberOrFilenameAwkward {
public static void main(String[] args) throws Exception {
int number;
try {
number = Integer.parseInt(args[0]);
} catch (NumberFormatException thisIsVeryUgly) {
Scanner scanner = new Scanner(new FileReader(args[1]));
String numberInFile = scanner.next();
number = Integer.parseInt(numberInFile);
}
System.out.println(number);
}
}
That is a terrible solution and screams for using a command line parsing library like JewelCLI or commons-cli to solve it cleanly.
FileNotFoundExceptionwhich suggests that your program can't find the specified file. I'd focus on solving that problem firstint coup = Integer.parseInt(args[1]);?args[0], so what are you doing withargs[1]?