md5.java

简单的sso实现

/**
 * 
 */
package org.yqing.util;

import java.security.MessageDigest;

/**
 * @author cabby
 * <a href="mailto:[e-mail]">[e-mail]</a>
 * 2009-1-4 
 * project:sso
 */
public class MD5 {

	public final static String encode(String s) {
		char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
				'a', 'b', 'c', 'd', 'e', 'f' };
		try {
			byte[] strTemp = s.getBytes();
			MessageDigest mdTemp = MessageDigest.getInstance("MD5");
			mdTemp.update(strTemp);
			byte[] md = mdTemp.digest();
			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) {
			return null;
		}
	}
	
	public static void main(String[] args) {
		System.out.println(MD5.encode("aa"));
		String s1 = "hello world";
		String s2 = MD5.encode(s1);
		String s3 = MD5.encode(s1);
		if (s2.equals(s3)) {
			System.out.print("hello world！");
		}
	}
}