Java–用戶登錄（JDBC，MYSQL，Servlet）
博客說明
文章所涉及的資料來自互聯網整理和個人總結，意在於個人學習和經驗彙總，如有什麼地方侵權，請聯繫本人刪除，謝謝！
用戶登錄案例需求
- 編寫login.html登錄頁面
username & password 兩個輸入框 - 使用Druid數據庫連接池技術,操作mysql，day14數據庫中user表
- 使用JdbcTemplate技術封裝JDBC
- 登錄成功跳轉到SuccessServlet展示：登錄成功！用戶名,歡迎您
- 登錄失敗跳轉到FailServlet展示：登錄失敗，用戶名或密碼錯誤
登錄頁面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="/login_test/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>
創建數據庫
CREATE DATABASE login;
USE login;
CREATE TABLE user(
id INT PRIMARY KEY auto_increment,
username VARCHAR(32) UNIQUE NOT NULL,
password VARCHAR(32) NOT NULL
)
配置文件
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///login
username=root
password=root
initialSize=5
maxActive=10
maxWait=3000
項目依賴
創建用戶實體類
創建包cn.guizimo.domain,創建類User
package cn.guizimo.domain;
/**
* @author tanglei
* @date 2020/6/22 10:28 上午
*/
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 + '\'' +
'}';
}
}
創建工具類
創建包cn.guizimo.util,編寫工具類JDBCUtils
package cn.guizimo.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;
/**
* @author tanglei
* @date 2020/6/22 10:38 上午
*/
public class JDBCUtils {
private static DataSource ds ;
static {
try {
//1.加載配置文件
Properties pro = new Properties();
//使用ClassLoader加載配置文件，獲取字節輸入流
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
//2.初始化連接池對象
ds = DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 獲取連接池對象
*/
public static DataSource getDataSource(){
return ds;
}
/**
* 獲取連接Connection對象
*/
public static Connection getConnection() throws SQLException {
return ds.getConnection();
}
}
創建數據操作類
創建包cn.guizimo.dao,創建類UserDao,提供login方法
package cn.guizimo.dao;
import cn.guizimo.domain.User;
import cn.guizimo.util.JDBCUtils;
import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
/**
* @author tanglei
* @date 2020/6/22 10:34 上午
*/
public class UserDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
public User login(User loginUser) {
try {
String sql = "select * from user where username = ? and password = ?";
User user = template.queryForObject(sql,
new BeanPropertyRowMapper<User>(User.class),
loginUser.getUsername(), loginUser.getPassword());
return user;
} catch (DataAccessException e) {
e.printStackTrace();
return null;
}
}
}
創建servlet類
cn.guizimo.web.servlet.LoginServlet類
package cn.guizimo.web.servlet;
import cn.guizimo.dao.UserDao;
import cn.guizimo.domain.User;
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;
/**
* @author tanglei
* @date 2020/6/22 11:15 上午
*/
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//1.設置編碼
req.setCharacterEncoding("utf-8");
//2.獲取請求參數
String username = req.getParameter("username");
String password = req.getParameter("password");
//3.封裝user對象
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);
//4.調用UserDao的login方法
UserDao dao = new UserDao();
User user = dao.login(loginUser);
//5.判斷user
if(user == null){
//登錄失敗
req.getRequestDispatcher("/failServlet").forward(req,resp);
}else{
//登錄成功
//存儲數據
req.setAttribute("user",user);
//轉發
req.getRequestDispatcher("/successServlet").forward(req,resp);
}
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doGet(req,resp);
}
}
cn.guizimo.web.servlet.FailServlet類
package cn.guizimo.web.servlet;
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;
/**
* @author tanglei
* @date 2020/6/22 11:26 上午
*/
@WebServlet("/failServlet")
public class FailServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//設置編碼
resp.setContentType("text/html;charset=utf-8");
//輸出
resp.getWriter().write("登錄失敗，用戶名或密碼錯誤");
}
}
cn.guizimo.web.servlet.SuccessServlet類
package cn.guizimo.web.servlet;
import cn.guizimo.domain.User;
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;
/**
* @author tanglei
* @date 2020/6/22 11:31 上午
*/
@WebServlet("/successServlet")
public class SuccessServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
this.doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//獲取request域中共享的user對象
User user = (User) req.getAttribute("user");
if(user != null){
//設置編碼
resp.setContentType("text/html;charset=utf-8");
//輸出
resp.getWriter().write("登錄成功！"+user.getUsername()+",歡迎您");
}
}
}
運行
在瀏覽器中打開http://localhost:8080/login_test/login.html
登錄成功
登錄失敗
感謝
萬能的網絡
以及勤勞的自己