每日总结7

今日学习时长很长，上午和maya老师激情对线，了解了英语口语的发音技巧，使自己的口语发音更加流畅。

然后是数据库课程，了解了数据库的基本原理，下午是python课程，了解了一些基本的语法。和一些基础代码，

package 成绩管理;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class UserDao {
private static final String DB_URL = "jdbc:mysql://localhost:3306/your_database";
private static final String DB_USERNAME = "your_username";
private static final String DB_PASSWORD = "your_password";

public User getUser(String username, String password, String role) {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;

try {
Class.forName("com.mysql.jdbc.Driver");
connection = DriverManager.getConnection(DB_URL, DB_USERNAME, DB_PASSWORD);

String sql = "SELECT * FROM users WHERE username = ? AND password = ? AND role = ?";
preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, username);
preparedStatement.setString(2, password);
preparedStatement.setString(3, role);

resultSet = preparedStatement.executeQuery();
if (resultSet.next()) {
return new User(username, password, role);
}
} catch (ClassNotFoundException | SQLException e) {
e.printStackTrace();
} finally {
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (preparedStatement != null) {
try {
preparedStatement.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

return null;
}
}