MD5加密

import java.security.*;
import java.util.*;

public class MD5
{
    private String inStr;
    private MessageDigest md5;

    /**
     * Constructs the MD5 object and sets the string whose MD5 is to be computed.
     *
     * @param inStr the <code>String</code> whose MD5 is to be computed
     */
    public MD5(String inStr)
    {
     this.inStr = inStr;
        try
        {
         this.md5 = MessageDigest.getInstance("MD5");
        }
        catch (Exception e)
        {
         System.out.println(e.toString());
         e.printStackTrace();
        }
    }

    /**
     * Computes the MD5 fingerprint of a string.
     *
     * @return the MD5 digest of the input <code>String</code>
     */
    public String compute()
    {
     // convert input String to a char[]
     // convert that char[] to byte[]
     // get the md5 digest as byte[]
     // bit-wise AND that byte[] with 0xff
     // prepend "0" to the output StringBuffer to make sure that we don't end up with
     // something like "e21ff" instead of "e201ff"

     char[] charArray = this.inStr.toCharArray();
 
     byte[] byteArray = new byte[charArray.length];
 
     for (int i=0; i<charArray.length; i++)
      byteArray[i] = (byte) charArray[i];
 
     byte[] md5Bytes = this.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();
    }
    

    public static void main(String[] args)
     {
       MD5 md5=new MD5("abc");
       String postString = md5.compute();
       System.out.println(postString);
       if(postString.equals("900150983cd24fb0d6963f7d28e17f72"))
       {
        System.out.println("true");
       }
       else
        System.out.println("false");
     }

}