import java.io.*;
import java.awt.*;
import java.awt.event.*;

public class Example10_6{

public static void main(String args[]){

char a[]="今晚10点进攻".toCharArray();
int n=0,m=0;

try{

File f=new File("secert.txt");
for(int i=0;i<a.length;i++){
a[i]=(char)(a[i]^'R');

}

FileWriter out=new FileWriter(f);
out.write(a,0,a.length);
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);
System.out.println("");
System.out.println("明文");

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);
}
in.close();
}

catch(IOException e){
System.out.println("File read Error");
}
}
}

package com.design.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class test {

    public static void main(String args[]) {

        byte[] a="今晚10点进攻".getBytes();
        //char a[] = "今晚10点进攻".toCharArray();
        int n = 0, m = 0;

        try {

            File f = new File("D://secert.txt");
            for (int i = 0; i < a.length; i++) {
                a[i] =  (byte) (a[i] ^ 'R');

            }

            FileOutputStream out=new FileOutputStream(f);
            //FileWriter out = new FileWriter(f);
            out.write(a, 0, a.length);
            out.close();
            FileInputStream in=new FileInputStream(f);
        //    FileReader in = new FileReader(f);
            //char tom[] = new char[10];
            byte tom[]=new byte[1024];
            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);
            in=new FileInputStream(f);
            System.out.println("");
            System.out.println("明文");

            while ((n = in.read(tom, 0, 10)) != -1) {
                for (int i = 0; i < n; i++) {
                    tom[i] = (byte) (tom[i] ^ 'R');
                }
                String s = new String(tom, 0, n);
                System.out.print(s);
            }
            in.close();
        }

        catch (IOException e) {
            System.out.println("File read Error");
        }
    }
}