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
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
<!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
driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/student
username=root
password=root
maxActive=10
maxWait=1000
|
5、创建包cn.itcast.domain，创建类User
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
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
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
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
|
