package org.bearfly.test.md5;
 
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
 
public class MD5Utils {
 public static void main(String[] args){
 System.out.println(getMd5String(""));
 System.out.println(MD5("good"));
 }
 
 
 public final static String MD5(String s) {
 char hexDigits[] = { '0', '1', '2', '3', '4',
 '5', '6', '7', '8', '9',
 'A', 'B', 'C', 'D', 'E', 'F' };
 try {
 byte[] btInput = s.getBytes();
 //获得MD5摘要算法的 MessageDigest 对象
 MessageDigest mdInst = MessageDigest.getInstance("MD5");
 //使用指定的字节更新摘要
 mdInst.update(btInput);
 //获得密文
 byte[] md = mdInst.digest();
 //把密文转换成十六进制的字符串形式
 int j = md.length;
 char str[] = new char[j * 2];
 int k = 0;
 for (int i = 0; i < j; i++) {
 byte byte0 = md[i];
 str[k++] = hexDigits[byte0 >>> 4 & 0xf];
 str[k++] = hexDigits[byte0 & 0xf];
 }
 return new String(str);
 }
 catch (Exception e) {
 e.printStackTrace();
 return null;
 }
 }
 
 
 
 public static String getMd5String(String str){
 MessageDigest messageDigest = null; 
 
 try { 
 messageDigest = MessageDigest.getInstance("MD5"); 
 
 messageDigest.reset(); 
 
 messageDigest.update(str.getBytes("UTF-8")); 
 } catch (NoSuchAlgorithmException e) { 
 System.out.println("NoSuchAlgorithmException caught!"); 
 System.exit(-1); 
 } catch (UnsupportedEncodingException e) { 
 e.printStackTrace(); 
 } 
 
 byte[] byteArray = messageDigest.digest(); 
 
 StringBuffer md5StrBuff = new StringBuffer(); 
 
 for (int i = 0; i < byteArray.length; i++) { 
 if (Integer.toHexString(0xFF & byteArray[i]).length() == 1) 
 md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i])); 
 else 
 md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i])); 
 } 
 
 return md5StrBuff.toString(); 
 }
}

2、JavaScript:
md5.js

md5.html

补充：javascript 的MD5代码备份，跟java互通