자바 DES 복호화 파일

import com.mchange.v2.io.DirectoryDescentUtils;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import java.io.*;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.security.Key;
import java.security.SecureRandom;

/**
 * Created by John on 2015/3/24.
 */
public class DESUtil {

    public static String keyPath;
    public static void saveDesKey() {
        try {
            SecureRandom sr = new SecureRandom();
            KeyGenerator kg = KeyGenerator.getInstance("DES");
            kg.init(sr);
            FileOutputStream fos = new FileOutputStream(keyPath);
            ObjectOutputStream oos = new ObjectOutputStream(fos);

            //generate key
            Key key = kg.generateKey();
            oos.writeObject(key);
            oos.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    public static Key getKey() {
        Key kp = null;

        try {
         //   String fileName = "D:/deskey.xml";
        /**    InputStream is = DESTest.class.getClassLoader()
                    .getResourceAsStream(fileName);
         **/
            Path path = Paths.get(keyPath);
        InputStream is = Files.newInputStream(path);
            ObjectInputStream oos = new ObjectInputStream(is);

            kp = (Key) oos.readObject();
            oos.close();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return kp;
    }


    /**
     *   file           destFile    * @param file
     *         c:/test/srcFile.txt   * @param destFile
     *            c:/     .txt
     */
    public static void encrypt(String file, String destFile) throws Exception {
        Cipher cipher = Cipher.getInstance("DES");
        cipher.init(Cipher.ENCRYPT_MODE, getKey());
        InputStream is = new FileInputStream(file);
        OutputStream out = new FileOutputStream(destFile);
        CipherInputStream cis = new CipherInputStream(is, cipher);
        byte[] buffer = new byte[1024];
        int r;
        while ((r = cis.read(buffer)) > 0) {
            out.write(buffer, 0, r);
        }
        cis.close();
        is.close();
        out.close();
    }

    /**
     *   file           destFile    * @param file
     *         c:/     .txt
     *
     * @param dest            c:/ test/     .txt
     */
    public static void decrypt(String file, String dest) throws Exception {
        Cipher cipher = Cipher.getInstance("DES");
        cipher.init(Cipher.DECRYPT_MODE, getKey());
        InputStream is = new FileInputStream(file);
        OutputStream out = new FileOutputStream(dest);
        CipherOutputStream cos = new CipherOutputStream(out, cipher);
        byte[] buffer = new byte[1024];
        int r;
        while ((r = is.read(buffer)) >= 0) {
            cos.write(buffer, 0, r);
        }
        cos.close();
        out.close();
        is.close();
    }

    public static void main(String[] args) throws Exception {

        //     c:\\gpi.key   
        keyPath = "c:\\gpi.key";
        saveDesKey();

        //  c:\src.xml  
        encrypt("C:\\src.xml", "c:\\encrypted.xml");

        //  c:\encrypted.xml  
        decrypt("c:\\encrypted.xml", "c:\\decrypted.xml");
    }
}