loginservlet.java

以mvc模式写的一个简单的留言管理系统!

package bbs;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;

public class LoginServlet
    extends HttpServlet {
    public void doPost(HttpServletRequest request, HttpServletResponse response) throws
        ServletException, IOException {
        doGet(request, response);
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws
        ServletException, IOException {
        String method = request.getParameter("method");
        if (method == null) {
            return;
        }
        else if (method.equalsIgnoreCase("user_add")) {
            user_add(request, response);
        }
        else if (method.equalsIgnoreCase("user_update")) {
            user_update(request, response);
        }
        else if (method.equalsIgnoreCase("user_login")) {
            user_login(request, response);
        }
    }

    private void user_login(HttpServletRequest request,
                            HttpServletResponse response) {
        String userName = (String) request.getParameter("username");
        String passWord = (String) request.getParameter("password");
        User user = new User();
        user.setUserName(userName);
        user.setPassWord(passWord);
        boolean isSuccess = false;
        try {
            isSuccess = UserHandle.userLogin(user);
        }
        catch (Exception es) {
            es.printStackTrace();
            isSuccess = false;
            request.setAttribute("login_error", es.getMessage());
        }
        String forward = null;
        if (isSuccess) {
            request.getSession().setAttribute("user", user);
            request.removeAttribute("login_error");
            forward = "index.jsp";
        }
        else {
            forward = "login.jsp";
            request.setAttribute("login_error", "鐢ㄦ埛鍚嶆垨瀵嗙爜涓嶅尮閰