loginservlet.java

张新曼 精通JSP Web 开发技术与典型应用 随书光盘源码

package ch24.Servlet;

import java.io.IOException;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import ch24.JavaBean.User;
import ch24.JavaBean.DB_User;
import ch24.JavaBean.MD5_Encoding;


/**
 * 
 * @author qq
 * 
 * 用户登陆
 */

public class LoginServlet extends javax.servlet.http.HttpServlet 
                            implements javax.servlet.Servlet {
	//构造函数
	public LoginServlet() {
		super();
	}
	
	//服务器端的验证、提交处理
	protected void doPost(HttpServletRequest request,HttpServletResponse response) 
	                 throws ServletException, IOException {
		response.setContentType("text/html;charset=GB2312");
		MD5_Encoding md5=new MD5_Encoding();
		
		// 获取提交的用户名：
		String UserName = request.getParameter("logname");
		// 获取提交的密码：
		String Password = request.getParameter("logpwd");
		// 对密码进行MD5数据加密
		String EnPwd =md5.getMD5ofStr(Password);

		String random = request.getParameter("random");
		String random2 = request.getSession().getAttribute("random").toString();
		if (!random.equals(random2)) {
			request.setAttribute("error", "输入的验证码不正确！");
			try {
				request.getRequestDispatcher("./Login.jsp").forward(request, response);
			} 
			catch (Throwable t) {
				getServletContext().log(t.getMessage());
			}
		}
		//核对用户名和密码，决定是否通过登陆验证
		DB_User dbuser = new DB_User();
		User user = dbuser.get(UserName, EnPwd);
		int userid=0;
		if (user != null) {
			// 登录成功时,把strUserName设成session变量UserName
			userid=user.getId();
			request.getSession(true).setAttribute("userid",String.valueOf(userid));
			request.getSession(true).setAttribute("username", UserName);
			try {
				request.getRequestDispatcher("./Welcome.jsp").forward(request,response);
			} 
			catch (Throwable t) {
				getServletContext().log(t.getMessage());
			}
		} else {
			// 否则（记录集为空），表明失败：
			request.setAttribute("error", "用户名与密码不匹配,登录失败,请重试！");
			try {
				request.getRequestDispatcher("./Login.jsp").forward(request, response);
			} 
			catch (Throwable t) {
				getServletContext().log(t.getMessage());
			}
		}
	}
}