上次写了一篇JDBC工具类实现登录功能，但是只能在控制台实现输入用户名密码。这次使用了Servlet来实现登录功能，可以通过在页面上输入账号密码，然后提交表单，查询数据库，从而实现登录功能。
1、配置文件，导入jar包
2、创建数据库环境
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use student;create table user( id int primary key auto_increment, username varchar(32), password varchar(32));insert into user values(null,'zhangsan','123');insert into user values(null,'lisi','234'); |
3、在web目录下创建HTML页面
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<!DOCTYPE html><html lang="en"><head> <meta charset="UTF-8"> <title>登录页面</title></head><body> <form action="/day14_request/loginServlet" method="post"> 用户名：<input type="text" name="username"><br> 密码：<input type="password" name="password"><br> <input type="submit" value="登录"> </form></body></html> |
4、在src下编写druid.properties文件
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driverClassName=com.mysql.jdbc.Driverurl=jdbc:mysql://localhost:3306/studentusername=rootpassword=rootmaxActive=10maxWait=1000 |
5、创建包cn.itcast.domain，创建类User
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package cn.itcast.domain;/* 用户的实体类 */public class User { private int id; private String username; private String password; public int getId() { return id; } public void setId(int id) { this.id = id; } 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; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", password='" + password + '\'' + '}'; }} |
6、创建包cn.itcast.util，编写工具类JDBCUtils
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package cn.itcast.util;import com.alibaba.druid.pool.DruidDataSourceFactory;import javax.sql.DataSource;import java.io.IOException;import java.io.InputStream;import java.sql.Connection;import java.sql.SQLException;import java.util.Properties;/* JDBC工具类，使用Durid连接池 */public class JDBCUtils { private static DataSource dataSource; static { try { //1、加载配置文件 Properties properties = new Properties(); InputStream resourceAsStream = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"); properties.load(resourceAsStream); //2、初始化连接池对象 dataSource = DruidDataSourceFactory.createDataSource(properties); } catch (IOException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } /** * 获取连接池对象 */ public static DataSource getDataSource() { return dataSource; } /** * 获取连接Connection对象 */ public static Connection getConnection() throws SQLException { return dataSource.getConnection(); }} |
7、创建包cn.itcast.dao，创建类UserDao，提供login方法
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package cn.itcast.dao;import cn.itcast.domain.User;import cn.itcast.util.JDBCUtils;import org.springframework.dao.DataAccessException;import org.springframework.jdbc.core.BeanPropertyRowMapper;import org.springframework.jdbc.core.JdbcTemplate;/** * 操作数据库中User表的类 */public class UserDao { //声明JDBCTemplate对象共用 private JdbcTemplate jdbcTemplate = new JdbcTemplate(JDBCUtils.getDataSource()); /** * 登录方法 * @param loginUser 只有用户和密码 * @return user 包含用户全部信息，没有查询到，返回null */ public User login(User loginUser) { try { //1、编写sql String sql = "select * from user where username = ? and password = ?"; //2、调用query方法 User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), loginUser.getUsername(),loginUser.getPassword()); return user; } catch (DataAccessException e) { e.printStackTrace();//记录日志 return null; } }} |
8、编写cn.itcast.web.servlet.LoginServlet类
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package cn.itcast.web.servlet;import cn.itcast.dao.UserDao;import cn.itcast.domain.User;import org.apache.commons.beanutils.BeanUtils;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 java.io.IOException;import java.lang.reflect.InvocationTargetException;import java.util.Map;@WebServlet("/loginServlet")public class LoginServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1、设置编码 request.setCharacterEncoding("utf-8"); /*//2、获取请求参数 String username = request.getParameter("username"); String password = request.getParameter("password"); //3、封装对象 User loginUser = new User(); loginUser.setUsername(username); loginUser.setPassword(password);*/ //2、获取所有请求参数(这里使用BeanUtils来简化操作) Map<String, String[]> parameterMap = request.getParameterMap(); //3.1 创建User对象 User loginUser = new User(); //3.2 使用BeanUtils对象 try { BeanUtils.populate(loginUser,parameterMap); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } //4、调用UserDao的login方法 UserDao userDao = new UserDao(); User user = userDao.login(loginUser); //5、判断user if (user == null) { //登录失败 request.getRequestDispatcher("/failServlet").forward(request,response); } else { //登录成功 //存储数据 request.setAttribute("user",user); //转发 request.getRequestDispatcher("/successServlet").forward(request,response); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request,response); }} |
运行结果：
1、目录结构
2、运行界面
3、输入用户名密码均正确
4、跳转到成功登录界面
5、输入用户名或密码错误时
6、跳转登录失败界面
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：https://blog.csdn.net/weixin_44668898/article/details/107542031
