package com.baobaotao.place;
…
public class DESEncryptUtil ...{
    public static Key createKey() throws NoSuchAlgorithmException ...{//创建一个密钥
        Security.insertProviderAt(new com.sun.crypto.provider.SunJCE(), 1);
        KeyGenerator generator = KeyGenerator.getInstance("DES");
        generator.init(new SecureRandom());
        Key key = generator.generateKey();
        return key;
    }
    public static Key getKey(InputStream is) ...{
        try ...{
            ObjectInputStream ois = new ObjectInputStream(is);
            return (Key) ois.readObject();
        } catch (Exception e) ...{
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    private static byte[] doEncrypt(Key key, byte[] data) ...{//对数据进行加密
        try ...{
            Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            byte[] raw = cipher.doFinal(data);
            return raw;
        } catch (Exception e) ...{
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    public static InputStream doDecrypt(Key key, InputStream in) ...{//对数据进行解密
        try ...{
            Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, key);
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            byte[] tmpbuf = new byte[1024];
            int count = 0;
            while ((count = in.read(tmpbuf)) != -1) ...{
                bout.write(tmpbuf, 0, count);
                tmpbuf = new byte[1024];
            }
            in.close();
            byte[] orgData = bout.toByteArray();
            byte[] raw = cipher.doFinal(orgData);
            ByteArrayInputStream bin = new ByteArrayInputStream(raw);
            return bin;
        } catch (Exception e) ...{
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    public static void main(String[] args) throws Exception ...{//提供了Java命令使用该工具的功能
        if (args.length == 2 && args[0].equals("key")) ...{// 生成密钥文件
            Key key = DESEncryptUtil.createKey();
            ObjectOutputStream oos = new ObjectOutputStream(
                    new FileOutputStream(args[1]));
            oos.writeObject(key);
            oos.close();
            System.out.println("成功生成密钥文件。");
        } else if (args.length == 3 && args[0].equals("encrypt")) ...{//对文件进行加密
            File file = new File(args[1]);
            FileInputStream in = new FileInputStream(file);
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            byte[] tmpbuf = new byte[1024];
            int count = 0;
            while ((count = in.read(tmpbuf)) != -1) ...{
                bout.write(tmpbuf, 0, count);
                tmpbuf = new byte[1024];
            }
            in.close();
            byte[] orgData = bout.toByteArray();
            Key key = getKey(new FileInputStream(args[2]));
            byte[] raw = DESEncryptUtil.doEncrypt(key, orgData);
            file = new File(file.getParent() + "\\en_" + file.getName());
            FileOutputStream out = new FileOutputStream(file);
            out.write(raw);
            out.close();
            System.out.println("成功加密，加密文件位于:"+file.getAbsolutePath());
        } else if (args.length == 3 && args[0].equals("decrypt")) ...{//对文件进行解密
            File file = new File(args[1]);
            FileInputStream fis = new FileInputStream(file);
            Key key = getKey(new FileInputStream(args[2]));
            InputStream raw = DESEncryptUtil.doDecrypt(key, fis);
            ByteArrayOutputStream bout = new ByteArrayOutputStream();
            byte[] tmpbuf = new byte[1024];
            int count = 0;
            while ((count = raw.read(tmpbuf)) != -1) ...{
                bout.write(tmpbuf, 0, count);
                tmpbuf = new byte[1024];
            }
            raw.close();
            byte[] orgData = bout.toByteArray();
            file = new File(file.getParent() + "\\rs_" + file.getName());
            FileOutputStream fos = new FileOutputStream(file);
            fos.write(orgData);
            System.out.println("成功解密，解密文件位于:"+file.getAbsolutePath());
        }
    }
}