Using Scanner to read several different unknown types of data : Scanner « File « Java Tutorial

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class MainClass {
  public static void main(String args[]) throws IOException {
    // Write output to a file.
    FileWriter fout = new FileWriter("test.txt");
    fout.write("int: 1  double 1.0  boolean true");
    fout.close();

    FileReader fin = new FileReader("Test.txt");

    Scanner src = new Scanner(fin);

    while (src.hasNext()) {
      if (src.hasNextInt()) {
        System.out.println("int: " + src.nextInt());
      } else if (src.hasNextDouble()) {
        System.out.println("double: " + src.nextDouble());
      } else if (src.hasNextBoolean()) {
        System.out.println("boolean: " + src.nextBoolean());
      } else {
        System.out.println(src.next());
      }
    }
    fin.close();
  }
}

int:
int: 1
double
double: 1.0
boolean
boolean: true

11.54.Scanner
	11.54.1.	Using Scanner to receive user input
	11.54.2.	Using Scanner: the complement of Formatter
	11.54.3.	In general, to use Scanner, follow this procedure
	11.54.4.	Creating a Scanner: read from standard input: Scanner conin = new Scanner(System.in)
	11.54.5.	Creating a Scanner to read from a string
	11.54.6.	Using Scanner to read several different unknown types of data
	11.54.7.	Setting Delimiters for Scanner
	11.54.8.	To obtain the current delimiter pattern: Pattern delimiter( )
	11.54.9.	Searching for the specified pattern within the next line of text
	11.54.10.	To find within the next count characters