package com.aok.test;

import java.security.MessageDigest;

public class MD5Test {

	public static void main(String[] args) {

		String result = MD5("123456");

		System.out.println("result: " + result);

		System.out.println("length: " + result.length());

	}

	/**

	 * 32位MD5加密的大写字符串

	 *

	 * @param s

	 * @return

	 */

	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;

		}

	}

}