javaweb登录注册功能实现 javaweb 登陆注册 入门 mysql数据库交互 web前后台交互 用户管理增删改查 实现登录 注册 登陆 JavaWeb 简单登陆注册

用户登录注册流程图

老版：

新版：

登陆界面

注册界面

登陆成功界面

LoginServlet

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 com.wzc.login.dao.UserDao;
import com.wzc.login.domain.User;/*** @description 登录请求处理类* @author WANGZIC*/
@WebServlet("/LoginServlet")
public class LoginServlet extends HttpServlet {private static final long serialVersionUID = 1L;public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=utf-8");//接收表单信息String username = request.getParameter("username");String password = request.getParameter("password");String verifyc  = request.getParameter("verifycode");//设置回显request.setAttribute("username", username);request.setAttribute("password", password);request.setAttribute("verifycode", verifyc);//获取验证码String svc =(String) request.getSession().getAttribute("sessionverify");//根据用户名查询用户User user =new UserDao().findUser(username);if(!svc.equalsIgnoreCase(verifyc)){request.setAttribute("loginError", "* 验证码错误");request.getRequestDispatcher("/login.jsp").forward(request, response);return;}if(user!=null){if(user.getPassword().equals(password)){request.getSession().setAttribute("user", user);response.sendRedirect("index.jsp");}else {request.setAttribute("loginError", "* 密码错误");request.getRequestDispatcher("/login.jsp").forward(request, response);}}else {request.setAttribute("loginError", "* 用户不存在");request.getRequestDispatcher("/login.jsp").forward(request, response);}}@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}}

RegistServlet

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 com.wzc.login.dao.UserDao;/*** @description 注册请求处理类* @author WANGZIC*/
@WebServlet("/RegistServlet")
public class RegistServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=utf-8");String username = request.getParameter("username");String password = request.getParameter("password");String rpsw = request.getParameter("rpsw");if(username==null||username.trim().isEmpty()){request.setAttribute("registError", "用户名不能为空");request.getRequestDispatcher("/regist.jsp").forward(request, response);return;}if(password==null||password.trim().isEmpty()){request.setAttribute("registError", "密码不能为空");request.getRequestDispatcher("/regist.jsp").forward(request, response);return;}if(!password.equals(rpsw)){request.setAttribute("registError", "密码不一致");request.getRequestDispatcher("/regist.jsp").forward(request, response);return;}UserDao u = new UserDao();boolean res = u.addUser(username,password);if(res){response.sendRedirect("index.jsp");}else {request.setAttribute("registError", "注册失败，该用户名已存在");request.getRequestDispatcher("/regist.jsp").forward(request, response);}}@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost(request, response);}
}

LogoutServlet

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;/*** Servlet implementation class LogoutServlet*/
@WebServlet("/LogoutServlet")
public class LogoutServlet extends HttpServlet {private static final long serialVersionUID = 1L;public LogoutServlet() {super();}protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {request.getSession().removeAttribute("user");response.sendRedirect("login.jsp");}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}}

VerifyCodeServlet

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** @description 验证码请求生成处理类* @author WANGZIC*/
@WebServlet("/VerifyCodeServlet")
public class VerifyCodeServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overridepublic void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {VerifyCode vc = new VerifyCode();request.getSession().setAttribute("sessionverify", vc.getText());vc.outputImage(90,35,response.getOutputStream());}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}/*** 验证码生成工具内部类* @author WANGZIC**/static class VerifyCode {private static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8','9','A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M','N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };private static Random random = new Random();private String text ;public String getText() {StringBuffer buffer = new StringBuffer();for (int i = 0; i < 4; i++) {buffer.append(CHARS[random.nextInt(CHARS.length)]);}text = buffer.toString();return text;}public void outputImage(int width,int height,OutputStream out) throws IOException{Color color = new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255));Color reverse = new Color(255 - color.getRed(), 255 - color.getGreen(), 255 - color.getBlue());BufferedImage bi = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);Graphics2D g = bi.createGraphics();g.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 25));g.setColor(color);g.fillRect(0, 0, width, height);g.setColor(reverse);g.drawString(text, 10, 26);for (int i = 0, n = random.nextInt(80); i < n; i++) {g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);}ImageIO.write(bi, "JPEG", out);}}
}

User

public class User {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;}}

UserDao

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;import com.wzc.login.domain.User;
/*** @description 数据库连接与操作类用于增删改查数据并返回给servlet使用* @author WANGZIC**/
public class UserDao {/** 数据库中运行下面的语句CREATE TABLE `user` (`username` varchar(255) NOT NULL,`password` varchar(255) DEFAULT NULL,PRIMARY KEY (`username`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;*///根据用户名查找用户密码public User findUser(String username){String sql = "select * from user where username=?";Connection con =getConnection();PreparedStatement pstmt =null;ResultSet rs = null;User user = new User();try {pstmt = con.prepareStatement(sql);pstmt.setString(1, username);rs = pstmt.executeQuery();if(rs.next()){user.setUsername(rs.getString("username"));user.setPassword(rs.getString("password"));}} catch (SQLException e) {e.printStackTrace();}finally {try {if(pstmt!=null)pstmt.close();if(con!=null)con.close();} catch (SQLException e) {		e.printStackTrace();}}return user;}//添加用户public boolean addUser(String username,String psw){Connection con = getConnection();PreparedStatement pstmt =null;String sql = "INSERT INTO user(username,password) VALUES(?,?)";boolean res = false;try {pstmt = con.prepareStatement(sql);pstmt.setString(1, username);pstmt.setString(2, psw);res = (pstmt.executeUpdate()==1);}catch (SQLException e) {if(!e.getMessage().contains("PRIMARY")){e.printStackTrace();}}finally {try {if(pstmt!=null)pstmt.close();if(con!=null)con.close();}catch (SQLException e) {	e.printStackTrace();}}return res;}//获得连接public static Connection getConnection(){String driver ="com.mysql.jdbc.Driver";//记得依赖mysql-jdbc驱动包String url ="jdbc:mysql://localhost:3306/mytest";//修改为自己的数据库String user ="root";//修改未自己数据库的用户名密码String password ="root";//修改未自己数据库的名密码Connection connection =null;try {Class.forName(driver);connection =DriverManager.getConnection(url, user, password);} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}return connection;}public static void main(String[] args) {//测试方法
//		System.out.println(new UserDao().findUser("123"));
//		new UserDao().addUser("1345", "1345");}}

新增了用户管理功能（对用户的增删改查）
源码仓库地址https://gitee.com/wangzic/login源码下载步骤如下图：

下载完源码之后请仔细阅读README.md文件，导入运行步骤和数据库表结构都在里面

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