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 mosesxin@gmail.com
 *
 */
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;
    }
}