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

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);
		}
		
	}
	
	@Override
	protected 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;

	@Override
	public 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);
		}
	}
	
	@Override
	protected 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;
	@Override
	public 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());
	}

	@Override
	protected 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）

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源码下载 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