表单数据处理类

1。将信息中的密码进行MD5转码
2。非法字符

package com.qinya.tools;

import java.security.*;

public class Encrypt {

	
	public static String encodeMD5(String str) {
		if (null==str) {
			return null;
		}
		StringBuilder sb = new StringBuilder();
		try {
			MessageDigest code = MessageDigest.getInstance("MD5");
			code.update(str.getBytes());
			byte[] bs = code.digest();
			for (int i = 0; i < bs.length; i++) {
				int v = bs[i] & 0xFF;
				if (v < 16) {
					sb.append(0);
				}
				sb.append(Integer.toHexString(v));
			}
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}

               //转化成十六进制的字符串
		return sb.toString().toUpperCase();
	}
         /*
           *是否存在非法字符“> >= <= ! + = | ()”
            */
	public static boolean isValidInput(String str) {
		return str.matches("[a-z0-9]+");
	}



}

实现用户登入的checkAccount()
在一个Servlet实现

private void checkAccount(HttpServletRequest request,
			HttpServletResponse response) throws UnsupportedEncodingException,
			ServletException, IOException {
		String information = "";
		userInfoDao = new UserInfoDao();
		session = request.getSession();
		String rand = (String) session.getAttribute("rand");
		String code = (String) request.getParameter("code");
		String account = request.getParameter("account");
		String password = request.getParameter("password");
		if (com.wy.tools.Encrypt.isValidInput(account)
				&& com.wy.tools.Encrypt.isValidInput(password)) {
			account = new String(account.getBytes("ISO8859_1"), "gb2312");
			password = com.wy.tools.Encrypt.encodeMD5(password);
		} else {
			information = "您输入的用户或密码存在非法字符串";
		}
		if (information.equals("")) {

			if (rand.equals(code)) {
				userInfo = userInfoDao.queryUserInfo(account);
				if (null != userInfo) {
					if (userInfo.getPassword().equals(password)) {
						session.setAttribute("userInfo", userInfo);
					} else {
						information = "您输入的密码不正确";
					}
				} else {
					information = "您输入的用户名不存在！";
				}
			} else {
				information = "您输入的验证码不正确！";
			}
		}
		System.out.println(information);
		request.setAttribute("information", information);
		request.getRequestDispatcher("index.jsp").forward(request, response);
	}

验证账号是否正确

public ActionForward checkUserInfo(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) {
		HttpSession session = request.getSession();
		userInfoForm = (UserInfoForm) form;
		dao = new UserInfoDao();
		String account = userInfoForm.getAccount();
		String password = com.wy.tools.Encrypt.encodeMD5(userInfoForm
				.getPassword());
		userInfoForm = dao.queryUserInfo(account);
		if (null == userInfoForm) {
			request.setAttribute("information", "用户名不存在！");
		} else if (!userInfoForm.getPassword().equals(password)) {
			request.setAttribute("information", "用户登录密码有误！");
		} else {
			request.setAttribute("information", "用户登录成功！");
			session.setAttribute("userInfo", userInfoForm);
		}
		return mapping.findForward("opeationUserInfo");
	}