Java基础-练习：文件加密解密

 

import java.io.*;

public class EncryptTest {

    public static void main(String[] args) {
        String path1 = "D:\\Java\\Test\\file1.txt";
        String path2 = "D:\\Java\\Test\\file2.txt";
        String path3 = "D:\\Java\\Test\\file3.txt";
        // 把一个文件加密到一个文件
        addPassword(path1, path2);
        // 从一个文件解密到另一个文件
        subPassword(path2, path3);
    }

    private static void addPassword(String path1, String path2) {
        // 准备
        // 声明
        FileReader dis = null;
        DataOutputStream dos = null;
        // 创建
        try {
            dis = new FileReader(path1);
            dos = new DataOutputStream(new FileOutputStream(path2));
            // 读取
            int i = dis.read();
            // 加密
            while (i != -1) {
                dos.writeInt(i + 2);

                i = dis.read();
            }
            // 刷新
            dos.flush();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("1");
        } finally {
            if (dis != null) {
                try {
                    dis.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (dos != null) {
                try {
                    dos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }

    private static void subPassword(String path2, String path3) {
        // 准备
        // 声明
        DataInputStream dis = null;
        FileWriter dos = null;
        // 创建
        try {
            dis = new DataInputStream(new FileInputStream(path2));
            dos = new FileWriter(path3);
            // 读取
            int i = dis.readInt();
            // 加密
            while (i != -1) {
                System.out.print((char) (i - 2));
                dos.write(i - 2);
                i = dis.readInt();
            }
            // 刷新
            dos.flush();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
        } finally {
            if (dis != null) {
                try {
                    dis.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (dos != null) {
                try {
                    dos.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}