io的几个小程序

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//简单的文件加密

import java.io.*;
import java.lang.String;
import java.awt.*;
import java.awt.event.*;
public class test
{
public static void main(String [] args)
{
    char a[]="今晚10点发起攻击".toCharArray();//把字符串存入字符数组中
    int n=0;
    try
    {
  File f=new File("secret.txt");//常见文件对象
  for(int i=0;i<a.length;i++)
     {a[i]=(char)(a[i]^'R');}//加密字符数组
  for(int i=0;i<a.length;i++)//输出加密后的内容
     {
   System.out.print(a[i]);
     }
     System.out.print("/n");

  FileWriter out=new FileWriter(f);
  out.write(a,0,a.length);//把字符数组的内容写到secret.txt中
  out.close();
  FileReader in=new FileReader(f);
  char tom[]=new char[10];
  System.out.println("密文：");
  while((n=in.read(tom,0,10))!=-1)
   {
   String s=new String(tom,0,n);
   System.out.print(s);
      }
       in.close();

    in=new FileReader(f);
    while((n=in.read(tom,0,10))!=-1)
     {
     for(int i=0;i<n;i++)
      {
        tom[i]=(char)(tom[i]^'R');
         }
            String s=new String(tom,0,n);
   System.out.print(s);
        }
    }
    catch (IOException e)
    {
     System.err.print(e);
    }
}
}

//读取文件时显示读取速度进度条

import javax.swing.*;
import java.io.*;

public class test3
{
public static void main(String[] args)
{
  byte b[]=new byte[30];
  try
  {
   FileInputStream input=new FileInputStream("1.txt");
            ProgressMonitorInputStream in=
    new ProgressMonitorInputStream(null,"读取文件",input);
   while(in.read(b)!=-1)
   {
    String s=new String (b);
    System.out.print(s);
    Thread.sleep(100);
   }
  }
  catch (Exception e)
  {
   System.out.print(e);
  }
}
}