MD5.java

package com.jakewharton;

import java.security.MessageDigest;

public class MD5 {
	public static String encode(String str){
        MessageDigest md5 = null;  
        try  
        {
            md5 = MessageDigest.getInstance("MD5"); 
        }catch(Exception e)  
        {  
            e.printStackTrace();  
            return "";  
        }  
          
        char[] charArray = str.toCharArray();  
        byte[] byteArray = new byte[charArray.length];  
          
        for(int i = 0; i < charArray.length; i++)  
        {  
            byteArray[i] = (byte)charArray[i];  
        }  
        byte[] md5Bytes = md5.digest(byteArray);  
          
        StringBuffer hexValue = new StringBuffer();  
        for( int i = 0; i < md5Bytes.length; i++)  
        {  
            int val = ((int)md5Bytes[i])&0xff;  
            if(val < 16)  
            {  
                hexValue.append("0");  
            }  
            hexValue.append(Integer.toHexString(val));  
        }  
        return hexValue.toString();  		
	}
}