JSP+servlet+Dao实现简单登录功能_用户2104215837

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JSP+servlet+Dao实现简单登录功能

(2017-12-13 08:46:02)

分类：编程之路

今天来给大家讲解一下登录界面的简单操作，废话少说直接开始：

关于DBUtils.java的设置：

package login;

import java.sql.DriverManager;

import java.sql.Connection;

public class DBUtil {

private static Connection conn = null;

public static Connection getCon() {

try {

Class.forName("com.mysql.jdbc.Driver");

String user = "root";

String pwd = "";

String url = "jdbc:mysql://localhost:3306/test";

conn = DriverManager.getConnection(url, user, pwd);

} catch (Exception e) {

e.printStackTrace();

}

return conn;

}

LoginDao.java:

package login;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

public class LoginDao {

private static LoginDao instance = null;

public static LoginDao getInstance() {

if (instance == null) {

instance = new LoginDao();

}

return instance;

}

// 保存用户注册信息

public UserBean findUser(String username) {

Connection conn = null;

PreparedStatement stat=null;

UserBean user = new UserBean();

try {

conn = DBUtil.getCon(); // 建立数据库连接

stat=conn.prepareStatement("select * from user where username= '"+username+"'");

ResultSet rs = stat.executeQuery();

while(rs.next()){

// int id=rs.getInt("id");

user.setUsername(rs.getString("username"));

user.setPassword(rs.getString("password"));

}

} catch (Exception e) {

e.printStackTrace();

} finally {

try {

conn.close();

} catch (SQLException e) {

e.printStackTrace();

}

return user;

}

User类（javabean）：

package login;

public class UserBean {

private String username = "";

private String password = "";

public String getUsername() {

return username;

}

public void setUsername(String username) {

this.username = username;

}

public String getPassword() {

return password;

}

public void setPassword(String password) {

this.password = password;

}

Servlet类：

package login;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

public class UserServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

doPost(request,response);

}

public void doPost(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, IOException {

HttpSession session = req.getSession();

UserBean user = new UserBean();

String username = req.getParameter("username");

String pwd = req.getParameter("pwd");

// account.setPassword(pwd);

// account.setUsername(username);

LoginDao dao = new LoginDao();

user = dao.findUser(username);

// 用户不存在

if(user.getUsername()==null||"".equals(user.getUsername())) {

String login_fail = "fail.jsp";

resp.sendRedirect(login_fail);

}else {

session.setAttribute("account", user);

String login_suc = "success.jsp";

resp.sendRedirect(login_suc);

return;

}

// if((username != null)&&(username.trim().equals("jsp"))) {

// if((pwd != null)&&(pwd.trim().equals("1"))) {

// System.out.println("success");

// session.setAttribute("account", account);

// String login_suc = "success.jsp";

// resp.sendRedirect(login_suc);

// return;

// }

// String login_fail = "fail.jsp";

// resp.sendRedirect(login_fail);

// return;

}

web.xml需要设置一下servlet关联：

This is the description of my J2EE component

This is the display name of my J2EE component

/login

以及前台的页面需要：

fail.jsp:

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