MD5 的 Java 調用

package test; 

import java.security.MessageDigest; 

/** 

 * <p>Title: </p> 

 * <p>Description: </p> 

 * <p>Copyright: Copyright (c) 2003</p> 

 * <p>Company: </p> 

 * @author unascribed 

 * @version 1.0 

 */ 



public class StringUtil { 



  private final static String[] hexDigits = { 

      "0", "1", "2", "3", "4", "5", "6", "7", 

      "8", "9", "a", "b", "c", "d", "e", "f"}; 



  /** 

   * 轉換字節數組爲16進制字串 

   * @param b 字節數組 

   * @return 16進制字串 

   */ 



  public static String byteArrayToHexString(byte[] b) { 

    StringBuffer resultSb = new StringBuffer(); 

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

      resultSb.append(byteToHexString(b[i])); 

    } 

    return resultSb.toString(); 

  } 



  private static String byteToHexString(byte b) { 

    int n = b; 

    if (n < 0) 

      n = 256 + n; 

    int d1 = n / 16; 

    int d2 = n % 16; 

    return hexDigits[d1] + hexDigits[d2]; 

  } 



  public static String MD5Encode(String origin) { 

    String resultString = null; 



    try { 

      resultString=new String(origin); 

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

      resultString=byteArrayToHexString(md.digest(resultString.getBytes())); 

    } 

    catch (Exception ex) { 



    } 

    return resultString; 

  } 



  public static void main(String[] args){ 

    System.err.println(MD5Encode("a")); 

  } 

}