I can read file using java.io and java.util.Scanner but I don't know how to read file using only java.util.Scanner:
import java.io.*;
import java.util.Scanner;
public class Main {
public static void main(String[] args) throws IOException {
String filePath = "C:\\IdeaProjects\\test\\src\\input.txt";
Scanner sc = new Scanner(new File(filePath));
int a, b;
a = sc.nestInt();
b = sc.nextInt();
}
}
Can someone help?
Since Scanner requires a java.io.File object, I don't think there's a way to read with Scanner only without using any java.io classes.
Here are two ways to read a file with the Scanner class - using default encoding and an explicit encoding. This is part of a long guide of how to read files in Java.
Scanner – Default Encoding
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReadFile_Scanner_NextLine {
public static void main(String [] pArgs) throws FileNotFoundException {
String fileName = "c:\\temp\\sample-10KB.txt";
File file = new File(fileName);
try (Scanner scanner = new Scanner(file)) {
String line;
boolean hasNextLine = false;
while(hasNextLine = scanner.hasNextLine()) {
line = scanner.nextLine();
System.out.println(line);
}
}
}
}
Scanner – Explicit Encoding
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class ReadFile_Scanner_NextLine_Encoding {
public static void main(String [] pArgs) throws FileNotFoundException {
String fileName = "c:\\temp\\sample-10KB.txt";
File file = new File(fileName);
//use UTF-8 encoding
try (Scanner scanner = new Scanner(file, "UTF-8")) {
String line;
boolean hasNextLine = false;
while(hasNextLine = scanner.hasNextLine()) {
line = scanner.nextLine();
System.out.println(line);
}
}
}
}
if you want to read the file until the end:
String filePath = "C:\\IdeaProjects\\test\\src\\input.txt";
File file = new File(filePath);
try {
Scanner sc = new Scanner(file);
while (sc.hasNextLine()) {
int i = sc.nextInt();
System.out.println(i);
}
sc.close();
}
catch (FileNotFoundException e) {
e.printStackTrace();
}
p.s If every line have only Integer I suggest you to use
Integer.parseInt(sc.readLine());
instead of sc.nextInt();
If you cant read please send me file Context
Well, if you are using a Mac, you type this into the terminal file.java<input.txt and to output to a file you type this: file.java>output.txt output.txt is a non-existing file, while input.txt is a pre-existing file.
