关于一个简易的html登陆界面并且连接数据库判断
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2022-05-03 10:24:23
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关于一个简易的html登陆界面并且连接数据库判断
所需要：数据库连接池druid，和tomcat服务器
login.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="/carrent/UserLoginServlet" 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>
druid配置文件
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/carrent
username=root
password=root
初始化的连接数量
initialSize=5
最大连接数
maxActive=10
最大等待时间
maxWait=3000
JDBC的工具类，使用Druid连接池
package cn.web.utils;
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的工具类 使用Druid连接池
*/
public class JDBCUtils {
private static DataSource ds;
static {
try {
// 1.加载配置文件
Properties properties = new Properties();
//使用Class.loader来加载配置文件，获取字节输入流
InputStream resourceAsStream = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
properties.load(resourceAsStream);
ds = DruidDataSourceFactory.createDataSource(properties);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
// 2.初始化连接池
}
/**
* 获取连接池对象
*/
public static DataSource getDataSource(){
return ds;
}
/**
* 获取连接Connection对象
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
创建登陆对象
package cn.web.person;
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;
}
}
用户登录类
package cn.web.login;
import cn.web.person.User;
import cn.web.utils.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
public class UserLogin {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
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 = template.queryForObject(sql,
new BeanPropertyRowMapper<>(User.class),
loginUser.getUsername(), loginUser.getPassword());
return user;
} catch (DataAccessException e) {
e.printStackTrace();//记录日志
return null;
}
}
}
判断登录是否成功
package cn.web.UserServlet;
import cn.web.login.UserLogin;
import cn.web.person.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("/UserLoginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("utf-8");
Map<String, String[]> parameterMap = req.getParameterMap();
User loginUser = new User();
try {
BeanUtils.populate(loginUser,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
UserLogin userLogin = new UserLogin();
User user = userLogin.Login(loginUser);
//5.判断user
if(user == null){
//登录失败
req.getRequestDispatcher("/UserFailServlet").forward(req,resp);
}else {
//登录成功
//存储数据
req.setAttribute("user",user);
//转发
req.getRequestDispatcher("/UserSuccessServlet").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req, resp);
}
}
成功界面
package cn.web.UserServlet;
import cn.web.person.Admin;
import cn.web.person.User;
import cn.web.utils.JDBCUtils;
import org.springframework.jdbc.core.JdbcTemplate;
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;
@WebServlet("/UserSuccessServlet")
public class SuccessServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取req域共享的user对象
User user = (User) req.getAttribute("user");
if (user != null) {
//给页面写一句话
//设置编码
resp.setContentType("text/html;charset=utf-8");
//输出
resp.getWriter().write("登录成功"+ user.getUsername() + ",欢迎您");
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req, resp);
}
}
失败界面
package cn.web.UserServlet;
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;
@WebServlet("/UserFailServlet")
public class FailServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//设置编码
resp.setContentType("text/html;charset=utf-8");
//输出
resp.getWriter().write("登录失败，用户名或密码错误");
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req, resp);
}
}
关于数据库
演示
登录：
登录成功：
登录失败：
如何登录？
1.首先需要启动启动tomcat服务器，把端口号8080修改为80.
并且设置虚拟目录为/carrent
2.进入：因为进入的界面为login.html故网址为：localhost/carrent/login.html，后续只需要输入数据库中存入的数据即可。若没有修改端口号则http://localhost:8080/carrent/login.html.