共计 5881 个字符,预计需要花费 15 分钟才能阅读完成。
Java– 用户登录(JDBC,MYSQL,Servlet)
博客说明
文章所涉及的资料来自互联网整理和个人总结,意在于个人学习和经验汇总,如有什么地方侵权,请联系本人删除,谢谢!
用户登录案例需求
- 编写 login.html 登录页面
username & password 两个输入框 - 使用 Druid 数据库连接池技术, 操作 mysql,day14 数据库中 user 表
- 使用 JdbcTemplate 技术封装 JDBC
- 登录成功跳转到 SuccessServlet 展示:登录成功!用户名, 欢迎您
- 登录失败跳转到 FailServlet 展示:登录失败,用户名或密码错误
登录页面
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<form action="/login_test/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>
创建数据库
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
项目依赖
创建用户实体类
创建包 cn.guizimo.domain, 创建类 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 + '\'' +
'}';
}
}
创建工具类
创建包 cn.guizimo.util, 编写工具类 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. 加载配置文件
Properties pro = new Properties();
// 使用 ClassLoader 加载配置文件,获取字节输入流
InputStream is = JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties");
pro.load(is);
//2. 初始化连接池对象
ds = DruidDataSourceFactory.createDataSource(pro);
} catch (IOException e) {e.printStackTrace();
} catch (Exception e) {e.printStackTrace();
}
}
/**
* 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();
}
}
创建数据操作类
创建包 cn.guizimo.dao, 创建类 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;
}
}
}
创建 servlet 类
cn.guizimo.web.servlet.LoginServlet 类
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. 设置编码
req.setCharacterEncoding("utf-8");
//2. 获取请求参数
String username = req.getParameter("username");
String password = req.getParameter("password");
//3. 封装 user 对象
User loginUser = new User();
loginUser.setUsername(username);
loginUser.setPassword(password);
//4. 调用 UserDao 的 login 方法
UserDao dao = new UserDao();
User user = dao.login(loginUser);
//5. 判断 user
if(user == null){
// 登录失败
req.getRequestDispatcher("/failServlet").forward(req,resp);
}else{
// 登录成功
// 存储数据
req.setAttribute("user",user);
// 转发
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 类
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 {
// 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");
}
}
cn.guizimo.web.servlet.SuccessServlet 类
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 {
// 获取 request 域中共享的 user 对象
User user = (User) req.getAttribute("user");
if(user != null){
// 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");
}
}
}
运行
在浏览器中打开 http://localhost:8080/login_test/login.html
登录成功
登录失败
感谢
万能的网络
以及勤劳的自己
正文完