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();    }  }}