Java简单从文件读取和输出的实例

package ioTest;

import java.io.*;
import java.util.Scanner;

public class TestMain {

  public static void main(String[] args) {
    try {
      Scanner sc=new Scanner(new File("in.txt"));
      PrintStream ps=new PrintStream("out.txt");
      while(sc.hasNext()){
        int a=sc.nextInt();
        System.out.print(a+" ");
        ps.println(a);
      }
      
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

}