Java Web实现登录注册（超详细附代码）

4.登录的数据流程

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登录操作的主要调用流程图

Login.jsp

LoginServlet

UserDB

第一步

第二步

第三步

第四步

5.部分代码的展示

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5.1注册

register.jsp注册页面 通过表单实现跳转到servlet

<meta name=“viewport” content=“width=device-width”,initial-> world message board of the future Register

${message}

复制代码

RegisterServlet.java

业务层：处理注册业务

package Sevlet;

import java.io.IOException;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import javaBean.User;

import useBean.UserDB;

@WebServlet(“/RegistServlet”)

public class RegistServlet extends HttpServlet {

private static final long serialVersionUID = 1L;

String message =“”;

public RegistServlet() {

super();

}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

request.setCharacterEncoding(“utf-8”);

//获取隐藏域的信息

String action = request.getParameter(“action”);

String url =“register.jsp”;

if(action.equals(“regist”))

url = registerUser(request,response);

getServletContext().getRequestDispatcher(url).forward(request, response);

}

//注册函数

private String registerUser(HttpServletRequest request,HttpServletResponse response) {

String username = request.getParameter(“username”);

String password = request.getParameter(“password”);

String password2 = request.getParameter(“password2”);

String message = “”;

//得到HttpSession类型的对象

HttpSession session = request.getSession();

//将数据存储于User对象

User user = new User();

user.setusername (username);

user.setpassword(password);

String url = “/login.jsp”;

if(password.equals(password2))

{

if( !UserDB.UserExists(username) ) {

message = “Registration successful! and login in”;

session.setAttribute(“message”, message);

//将注册用户信息写入数据库

UserDB.insert(user);

return url;

}

else

{

message = “The user name already exists”;

url = “/register.jsp”;

session.setAttribute(“message”, message);

return url;

}

}

else

{

message = “The password is inconsistent”;

session.setAttribute(“message”, message);

url = “/register.jsp”;

return url;

}

}

}

复制代码

Dao层实现判断用户名是否存在和插入数据库的方法 UserDB.java

//注册时判断用户名是否存在

public static boolean UserExists(String username) {

//可以建立一个连接池保存一定数量的连接，当有对象需要数据库连接时，直接将这个连接返回给该对象，

ConnectionPool pool = ConnectionPool.getInstance();

Connection connection = pool.getConnection();

PreparedStatement ps = null;

ResultSet rs = null;

String qr = "SELECT username FROM User "+ “WHERE username = ?”;

try {

ps = connection.prepareStatement(qr);

ps.setString(1, username);

rs = ps.executeQuery();

return rs.next();

} catch (SQLException e) {

System.out.println(e);

return false;

} finally {

DBUtil.closeResultSet(rs);

DBUtil.closePreparedStatement(ps);

pool.freeConnection(connection);

}

}

//将注册用户信息保存至数据库

public static int insert(User user) {

ConnectionPool pool = ConnectionPool.getInstance();

Connection connection = pool.getConnection();

PreparedStatement ps = null;

String qr = “INSERT INTO User (username, password)”+“VALUES (?, ?)”;

try {

ps = connection.prepareStatement(qr);

ps.setString(1, user.getusername());

ps.setString(2, user.getpassword());

return ps.executeUpdate();

} catch (SQLException e) {

System.out.println(e);

return 0;

} finally {

DBUtil.closePreparedStatement(ps);

pool.freeConnection(connection);

}

}

复制代码

5.2登录

login.jsp登录界面 通过表单实现跳转到servlet

<meta name=“viewport” content=“width=device-width”,initial-> world message board of the future login

register

${message}

复制代码

LoginServlet.java 业务层：处理登录业务

package Sevlet;

import java.io.IOException;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

最后

金三银四到了，送上一个小福利！

orm>

${message}

复制代码

LoginServlet.java 业务层：处理登录业务

package Sevlet;

import java.io.IOException;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

最后

金三银四到了，送上一个小福利！

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[外链图片转存中…(img-umNcoe1u-1714309681690)]

[外链图片转存中…(img-NRZXbUfw-1714309681691)]

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