DES 加密解密 文件工具类

public class DESEncrypt {

    /** 加密工具 */
    private Cipher encryptCipher = null;

    /** 解密工具 */
    private Cipher decryptCipher = null;
    private static String keyVal = "asdf1234";

    public DESEncrypt(){
        try {
            this.initialize_encryptKey(keyVal);
            this.initalize_dencryptkey(keyVal);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void initialize_encryptKey(String keyValue) throws Exception{
            Key key = getKey(keyValue.getBytes());
        encryptCipher = Cipher.getInstance("DES");
        encryptCipher.init(Cipher.ENCRYPT_MODE, key);
    }

    public void initalize_dencryptkey(String keyValue) throws Exception {
                Key key = getKey(keyValue.getBytes());
        decryptCipher = Cipher.getInstance("DES");
        decryptCipher.init(Cipher.DECRYPT_MODE, key);
    }

    /**
     * 从指定字符串生成密钥，密钥所需的字节数组长度为8位 不足8位时后面补0，超出8位只取前8位
     *
     * @param arrBTmp
     *            构成该字符串的字节数组
     * @return 生成的密钥
     * @throws java.lang.Exception
     */
    private Key getKey(byte[] arrBTmp) throws Exception {
        // 创建一个空的8位字节数组（默认值为0）
        byte[] arrB = new byte[];

        // 将原始字节数组转换为8位
        for (int i = ; i < arrBTmp.length && i < arrB.length; i++) {
            arrB[i] = arrBTmp[i];
        }
        // 生成密钥
        Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES");
        return key;
    }

    /**
     * 加密字节数组
     *
     * @param arrB
     *            需加密的字节数组
     * @return 加密后的字节数组
     * @throws Exception
     */
    public byte[] encrypt(byte[] arrB) throws Exception {
        return encryptCipher.doFinal(arrB);
    }

    /**
     * 解密字节数组
     *
     * @param arrB
     *            需解密的字节数组
     * @return 解密后的字节数组
     * @throws Exception
     */
    public byte[] decrypt(byte[] arrB) throws Exception {
        return decryptCipher.doFinal(arrB);
    }

    /**
     * 文件file进行加密并保存目标文件destFile中
     *
     * @param file
     *            要加密的文件 如c:/test/srcFile.txt
     * @param destFile
     *            加密后存放的文件名 如c:/加密后文件.txt
     */
    public void encrypt(String sourceFileName, String diminationFileName) throws Exception {
        InputStream is = new FileInputStream(sourceFileName);
        OutputStream out = new FileOutputStream(diminationFileName);
        CipherInputStream cis = new CipherInputStream(is, encryptCipher);
        byte[] buffer = new byte[];
        int r;
        while ((r = cis.read(buffer)) > -) {
            out.write(buffer, , r);
        }
        cis.close();
        is.close();
        out.close();
    }
    public void encrypt(File sourceFile, File diminationFile) throws Exception {
        InputStream is = new FileInputStream(sourceFile);
        OutputStream out = new FileOutputStream(diminationFile);
        CipherInputStream cis = new CipherInputStream(is, encryptCipher);
        byte[] buffer = new byte[];
        int r;
        while ((r = cis.read(buffer)) > -) {
            out.write(buffer, , r);
        }
        cis.close();
        is.close();
        out.close();
    }
    /**
     * 文件采用DES算法解密文件
     *
     * @param file
     *            已加密的文件 如c:/加密后文件.txt * @param destFile 解密后存放的文件名 如c:/
     *            test/解密后文件.txt
     */
    public void decrypt(String sourceFileName, String diminationFileName) throws Exception {
        InputStream is = new FileInputStream(sourceFileName);
        OutputStream out = new FileOutputStream(diminationFileName);
        CipherOutputStream cos = new CipherOutputStream(out, decryptCipher);
        byte[] buffer = new byte[];
        int r;
        while ((r = is.read(buffer)) >= ) {
            cos.write(buffer, , r);
        }
        cos.close();
        out.close();
        is.close();
    }
    public void decrypt(File sourceFile, File fileout ) throws Exception {
        InputStream is = new FileInputStream(sourceFile);
        OutputStream out = new FileOutputStream(fileout);
        CipherOutputStream cos = new CipherOutputStream(out, decryptCipher);
        byte[] buffer = new byte[];
        int r;
        while ((r = is.read(buffer)) >= ) {
            cos.write(buffer, , r);
        }
        cos.close();
        out.close();
        is.close();
    }
    public static void main(String[] args) throws Exception {
        DESEncrypt t = new DESEncrypt();
        //t.initialize_encryptKey(keyVal);
        //t.initalize_dencryptkey(keyVal);
         Long l = System.currentTimeMillis();
         System.out.println("开始"+l);
        t.encrypt("e:/ceshi.sql", "e:/ceshi2.sql");
        System.out.println("结束"+(System.currentTimeMillis()-l));
        t.decrypt("e:/ceshi2.sql", "e:/ceshi3.sql");
        System.out.println("结束2"+(System.currentTimeMillis()-l));
    }
}

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