Java实现MD5, SHA-1, BASE64, 3DES加解密方法

MD5、SHA-1为数字签名。
BASE64, 3DES为可逆加密方法。

import java.security.MessageDigest;



import javax.crypto.Cipher;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;



import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder;



/**

 * Java 加解密工具类

 * 

 * @author [email protected]

 *

 */

public class EncryptUtil {



    private static final String UTF8 = "utf-8";

    //定义 加密算法,可用 DES,DESede,Blowfish

    private static final String ALGORITHM_DESEDE = "DESede";



    /**

     * MD5数字签名

     * 

     * @param src

     * @return

     * @throws Exception

     */

    public String md5Digest(String src) throws Exception {

        // 定义数字签名方法, 可用：MD5, SHA-1

        MessageDigest md = MessageDigest.getInstance("MD5");

        byte[] b = md.digest(src.getBytes(UTF8));

        

        return this.byte2HexStr(b);

    }

    

    /**

     * BASE64 加密

     * 

     * @param src

     * @return

     * @throws Exception

     */

    public String base64Encoder(String src) throws Exception {

        BASE64Encoder encoder = new BASE64Encoder();

        return encoder.encode(src.getBytes(UTF8));

    }

    

    /**

     * BASE64解密

     * 

     * @param dest

     * @return

     * @throws Exception

     */

    public String base64Decoder(String dest) throws Exception {

        BASE64Decoder decoder = new BASE64Decoder();

        return new String(decoder.decodeBuffer(dest), UTF8);

    }

    

    /**

     * 3DES加密

     * 

     * @param src

     * @param key

     * @return

     * @throws Exception

     */

    public String desedeEncoder(String src, String key) throws Exception {

        SecretKey secretKey = new SecretKeySpec(build3DesKey(key), ALGORITHM_DESEDE);

        Cipher cipher = Cipher.getInstance(ALGORITHM_DESEDE);

        cipher.init(Cipher.ENCRYPT_MODE, secretKey);

        byte[] b = cipher.doFinal(src.getBytes(UTF8));

        

        return byte2HexStr(b);

    }

    

    /**

     * 3DES解密

     * 

     * @param dest

     * @param key

     * @return

     * @throws Exception

     */

    public String desedeDecoder(String dest, String key) throws Exception {

        SecretKey secretKey = new SecretKeySpec(build3DesKey(key), ALGORITHM_DESEDE);

        Cipher cipher = Cipher.getInstance(ALGORITHM_DESEDE);

        cipher.init(Cipher.DECRYPT_MODE, secretKey);

        byte[] b = cipher.doFinal(str2ByteArray(dest));

        

        return new String(b, UTF8);

    

    }

    

    /**

     * 字节数组转化为大写16进制字符串

     * 

     * @param b

     * @return

     */

    private String byte2HexStr(byte[] b) {

        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < b.length; i++) {

            String s = Integer.toHexString(b[i] & 0xFF);

            if (s.length() == 1) {

                sb.append("0");

            }

            

            sb.append(s.toUpperCase());

        }

        

        return sb.toString();

    }

    

    /**

     * 字符串转字节数组

     * 

     * @param s

     * @return

     */

    private byte[] str2ByteArray(String s) {

        int byteArrayLength = s.length()/2;

        byte[] b = new byte[byteArrayLength];

        for (int i = 0; i < byteArrayLength; i++) {

            byte b0 = (byte) Integer.valueOf(s.substring(i*2, i*2+2), 16).intValue();

            b[i] = b0;

        }

        

        return b;

    }

    

    /**

     * 构造3DES加解密方法key

     * 

     * @param keyStr

     * @return

     * @throws Exception

     */

    private byte[] build3DesKey(String keyStr) throws Exception {

        byte[] key = new byte[24];

        byte[] temp = keyStr.getBytes(UTF8);

        if (key.length > temp.length) {

            System.arraycopy(temp, 0, key, 0, temp.length);

        } else {

            System.arraycopy(temp, 0, key, 0, key.length);

        }

        

        return key;

    }

}