MD5 加密

MD5加密是很常见的应用，最近在项目中遇到一个关于注册后生成一个唯一的加密数字。共用了两个类。

方法如下：
1.

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

//import com.sun.org.apache.xml.internal.security.utils.Base64;

public class AppkeyUtil {
	
	 /** The signing algorithm.
	   */
	  private static final String SIGNING_ALGORITHM = "HmacSHA1";

	  /**
	   * The private constructor.
	   */
	  private AppkeyUtil() {
	    // nothing to do.
	  }

	  /** Signs the shopping cart using HMAC_SHA1.
	  *
	  * @param source The source to be signed.
	  *
	  * @param key The key to use to sign the xml. It cannot be null.
	  *
	  * @return The base64 encoded signature of the xml representation of this
	  * cart.
	  */
	 public static String sign(final String source, final String key) {
	   if (key == null) {
	     throw new IllegalArgumentException("key cannot be null");
	   }
	   Mac mac = null;

	   try {
	     mac = Mac.getInstance(SIGNING_ALGORITHM);
	     mac.init(new SecretKeySpec(key.getBytes(), SIGNING_ALGORITHM));
	   } catch (Exception e) {
	     throw new RuntimeException(e);
	   }

	   final byte[] result = mac.doFinal(source.getBytes());
	   final String signature = new String((Base64.encode(result)));
	   System.out.println(signature+".....appkey...");
	   return signature;
	 }
}

2.这里的数组中的数字可以根据需要变化

public class Base64 {	
	  private static final char last2byte = (char) Integer.parseInt("00000011", 2);  
	     private static final char last4byte = (char) Integer.parseInt("00001111", 2);  
	     private static final char last6byte = (char) Integer.parseInt("00111111", 2);  
	     private static final char lead6byte = (char) Integer.parseInt("11111100", 2);  
	     private static final char lead4byte = (char) Integer.parseInt("11110000", 2);  
	     private static final char lead2byte = (char) Integer.parseInt("11000000", 2);  
	     private static final char[] encodeTable = new char[]  
//	     { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};  
	     {'a', 'b', 'c', 'd', 'e', 'f', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'
	     , '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '1', '2', '3'
	    ,'a', 'b', 'c', 'd', 'e', 'f','a', 'b', 'c', 'd', 'e', 'f','a', 'b', 'c', 'd', 'e', 'f','a', 'b', 'c', 'd', 'e', 'f'};
	     /** 
	      * Base64 encoding. 
	      *  
	      * @param from 
	      *            The src data. 
	     * @return 
	      */  
	     public static String encode(byte[] from)  
	     {  
	         StringBuffer to = new StringBuffer((int) (from.length * 1.34) + 3);  
	         int num = 0;  
	         char currentByte = 0;  
	         for (int i = 0; i < from.length; i++)  
	        {  
	             num = num % 8;  
	             while (num < 8)  
	             {  
	                 switch (num)  
	                 {  
	                 case 0:  
	                     currentByte = (char) (from[i] & lead6byte);  
	                     currentByte = (char) (currentByte >>> 2);  
	                     break;  
	                 case 2:  
	                     currentByte = (char) (from[i] & last6byte);  
	                     break;  
	                 case 4:  
	                     currentByte = (char) (from[i] & last4byte);  
	                     currentByte = (char) (currentByte << 2);  
	                     if ((i + 1) < from.length)  
	                    {  
	                         currentByte |= (from[i + 1] & lead2byte) >>> 6;  
	                     }  
	                     break;  
	                 case 6:  
	                     currentByte = (char) (from[i] & last2byte);  
	                     currentByte = (char) (currentByte << 4);  
	                     if ((i + 1) < from.length)  
	                     {  
	                         currentByte |= (from[i + 1] & lead4byte) >>> 4;  
	                    }  
	                     break;  
	                 }  
	                 to.append(encodeTable[currentByte]);  
	                 num += 6;  
	             }  
	         }  
	        if (to.length() % 4 != 0)  
	         {  
	             for (int i = 4 - to.length() % 4; i > 0; i--)  
	             {  
	                to.append("");  
	             }  
	         }  
	         return to.toString();  
	     }  
}