MD5加密算法

package com.a.a;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5加密算法
 */
public class Md5Encrypt {
    /**
     * 对字符串进行MD5加密
     * @param text 明文
     * @return 密文
     */
    public static String md5(String text) {
        MessageDigest msgDigest = null;

        try {
            msgDigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            throw new IllegalStateException("System doesn't support MD5 algorithm.");
        }
        msgDigest.update(text.getBytes());

        byte[] bytes = msgDigest.digest();
        byte   tb;
        char   low;
        char   high;
        char   tmpChar;

        String md5Str = new String();
        for (int i = 0; i < bytes.length; i++) {
            tb = bytes[i];
            tmpChar = (char) ((tb >>> 4) & 0x000f);
            if (tmpChar >= 10) {
                high = (char) (('a' + tmpChar) - 10);
            } else {
                high = (char) ('0' + tmpChar);
            }
            md5Str += high;
            tmpChar = (char) (tb & 0x000f);
            if (tmpChar >= 10) {
                low = (char) (('a' + tmpChar) - 10);
            } else {
                low = (char) ('0' + tmpChar);
            }
            md5Str += low;
        }

        return md5Str;
    }
    
    public static void main(String[] args) {
    	String paseword="paseword";
    	System.out.println(paseword=Md5Encrypt.md5("xunhai"+paseword));
	}
}