课后作业----给文件进行加密

编写一个文件加解密程序，通过命令行完成加解密工作

思路：因为读取文件是可以按照字节读取，或者字符读取，所有我们可以按照读字节后把字节改了或者把字符改了。

按照字节的：

代码：

package com.testHomework;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;

public class FileAddCode {
    private static int numOfEncAndDec = 0x99;

    public static void main(String[] args) {
　　　　// 路径只能为觉得路径
        File file1 = new File("D:\jave编译器\com.shangxuetang\src\abc.txt");
        File file2 = new File("D:\jave编译器\com.shangxuetang\aaa.txt");
        //EnFile(file1,file2);
        DecFile(file2,file1);
    }
    
    // 文件的加密
    public static void EnFile(File srcFile,File tarFile) {
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            InputStream is = new FileInputStream(srcFile);
            OutputStream os = new FileOutputStream(tarFile,true);
            bis = new BufferedInputStream(is);
            bos = new BufferedOutputStream(os);
            //byte[] flush = new byte[1024];
            int len = -1;
            try {
                while((len=bis.read())!=-1) { //一个一个的读取文件内容
                    try {
                        bos.write(len^numOfEncAndDec); // 对文件内容进行一个一个的加密
                        bos.flush();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }finally {
            if(null!=bos) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }    
    }
    // 文件的加密
    public static void DecFile(File encFile,File decFile) {
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        try {
            InputStream is = new FileInputStream(encFile);
            OutputStream os = new FileOutputStream(decFile,true);
            bis = new BufferedInputStream(is);
            bos = new BufferedOutputStream(os);
            //byte[] flush = new byte[1024];
            int len = -1;
            try {
                while((len=bis.read())!=-1) { //一个一个的读取文件内容
                    try {
                        bos.write(len^numOfEncAndDec); // 对文件内容进行一个一个的加密
                        bos.flush();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }finally {
            if(null!=bos) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }    
    }

}

运行结果： 

字符

代码：

package com.testHomework;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.util.Arrays;

public class FileAddCode2 {
    private static int numOfEncAndDec = 0x99;

    public static void main(String[] args) {
        File file1 = new File("D:\jave编译器\com.shangxuetang\src\abc.txt");
        File file2 = new File("D:\jave编译器\com.shangxuetang\aaa.txt");
        /*try {
            EnFile(file1,file2);
        } catch (IOException e) {
            e.printStackTrace();
        }*/
        try {
            DecFile(file2,file1);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    // 文件的加密
    public static void EnFile(File srcFile,File tarFile) throws IOException {
        Reader reader = null;
        Writer writer = null;
        try {
             reader = new FileReader(srcFile);
             writer = new FileWriter(tarFile,true);
            //byte[] flush = new byte[1024];
            int len = -1;
            char[] flush = new char[1024];
            try {
                while((len=reader.read(flush))!=-1) { //一个一个的读取文件内容
                    try {
                        flush = addCode(flush,len);
                        writer.write(flush,0,len); // 对文件内容进行一个一个的加密
                        writer.flush();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }finally {
            if(null!=writer) {
                try {
                    writer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }    
    }
    // 文件的加密
    public static void DecFile(File encFile,File decFile) throws IOException {
        Reader reader = null;
        Writer writer = null;
        try {
             reader = new FileReader(encFile);
             writer = new FileWriter(decFile,true);
            //byte[] flush = new byte[1024];
            int len = -1;
            char[] flush = new char[1024];
            try {
                while((len=reader.read(flush))!=-1) { //一个一个的读取文件内容
                    try {
                        flush = deleteCode(flush,len);
                        writer.write(flush,0,len); // 对文件内容进行一个一个的加密
                        writer.flush();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }finally {
            if(null!=writer) {
                try {
                    writer.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    // 对单个字符进行加密
    public static char[] addCode(char[] temp,int len) {
        for(int i=0;i<len;i++) {
            temp[i] = (char) (temp[i]+5);
        }
        return temp;
    }
    // 对单个字符进行解密
    public static char[] deleteCode(char[] temp,int len) {
        for(int i=0;i<len;i++) {
            temp[i] = (char) (temp[i]-5);
        }
        return temp;
    }

}

 运行结果：