JavaWeb Servlet實現網頁登錄功能
上次寫瞭一篇JDBC工具類實現登錄功能，但是隻能在控制臺實現輸入用戶名密碼。這次使用瞭Servlet來實現登錄功能，可以通過在頁面上輸入賬號密碼，然後提交表單，查詢數據庫，從而實現登錄功能。
1、配置文件，導入jar包
2、創建數據庫環境
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目錄下創建HTML頁面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>登錄頁面</title>
</head>
<body>
<form action="/day14_request/loginServlet" method="post">
用戶名：<input type="text" name="username"><br>
密碼：<input type="password" name="password"><br>
<input type="submit" value="登錄">
</form>
</body>
</html>
4、在src下編寫druid.properties文件
driverClassName=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/student username=root password=root maxActive=10 maxWait=1000
5、創建包cn.itcast.domain，創建類User
package cn.itcast.domain;
/*
用戶的實體類
*/
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、創建包cn.itcast.util，編寫工具類JDBCUtils
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工具類，使用Durid連接池
*/
public class JDBCUtils {
private static DataSource dataSource;
static {
try {
//1、加載配置文件
Properties properties = new Properties();
InputStream resourceAsStream = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
properties.load(resourceAsStream);
//2、初始化連接池對象
dataSource = DruidDataSourceFactory.createDataSource(properties);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 獲取連接池對象
*/
public static DataSource getDataSource() {
return dataSource;
}
/**
* 獲取連接Connection對象
*/
public static Connection getConnection() throws SQLException {
return dataSource.getConnection();
}
}
7、創建包cn.itcast.dao，創建類UserDao，提供login方法
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;
/**
* 操作數據庫中User表的類
*/
public class UserDao {
//聲明JDBCTemplate對象共用
private JdbcTemplate jdbcTemplate = new JdbcTemplate(JDBCUtils.getDataSource());
/**
* 登錄方法
* @param loginUser 隻有用戶和密碼
* @return user 包含用戶全部信息，沒有查詢到，返回null
*/
public User login(User loginUser) {
try {
//1、編寫sql
String sql = "select * from user where username = ? and password = ?";
//2、調用query方法
User user = jdbcTemplate.queryForObject(sql,
new BeanPropertyRowMapper<User>(User.class),
loginUser.getUsername(),loginUser.getPassword());
return user;
} catch (DataAccessException e) {
e.printStackTrace();//記錄日志
return null;
}
}
}
8、編寫cn.itcast.web.servlet.LoginServlet類
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、設置編碼
request.setCharacterEncoding("utf-8");
/*//2、獲取請求參數
String username = request.getParameter("username");
String password = request.getParameter("password");
//3、封裝對象
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);*/
//2、獲取所有請求參數(這裡使用BeanUtils來簡化操作)
Map<String, String[]> parameterMap = request.getParameterMap();
//3.1 創建User對象
User loginUser = new User();
//3.2 使用BeanUtils對象
try {
BeanUtils.populate(loginUser,parameterMap);
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
//4、調用UserDao的login方法
UserDao userDao = new UserDao();
User user = userDao.login(loginUser);
//5、判斷user
if (user == null) {
//登錄失敗
request.getRequestDispatcher("/failServlet").forward(request,response);
} else {
//登錄成功
//存儲數據
request.setAttribute("user",user);
//轉發
request.getRequestDispatcher("/successServlet").forward(request,response);
}
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request,response);
}
}
運行結果：
1、目錄結構
2、運行界面
3、輸入用戶名密碼均正確
4、跳轉到成功登錄界面
5、輸入用戶名或密碼錯誤時
6、跳轉登錄失敗界面
以上就是本文的全部內容，希望對大傢的學習有所幫助，也希望大傢多多支持WalkonNet。