complete Restaurant Database Management System implementation

src/main/java/dev/dao/UserDao.java

@@ -1,6 +1,9 @@
 package dev.dao;
 
 import dev.model.User;
+import dev.database.DatabaseConnection;
+import java.lang.reflect.Field;
+import java.sql.*;
 
 public class UserDao {
 
@@ -8,14 +11,56 @@ public class UserDao {
 
         // TODO:
         // Insert user into database
+        String sql = "insert into users (username, password, email) values (?, ?, ?) ";
+        try (Connection conn = DatabaseConnection.getConnection(); PreparedStatement stmt = conn.prepareStatement(sql)){
+            Field usernameField = User.class.getDeclaredField("username");
+            Field passwordField = User.class.getDeclaredField("password");
+            Field emailField = User.class.getDeclaredField("email");
+            usernameField.setAccessible(true);
+            passwordField.setAccessible(true);
+            emailField.setAccessible(true);
+            stmt.setString(1, (String) usernameField.get(user));
+            stmt.setString(2, (String) passwordField.get(user));
+            stmt.setString(3, (String) emailField.get(user));
 
-        return false;
+            int rowsInserted = stmt.executeUpdate();
+            return rowsInserted > 0;
+        }
+        catch (SQLException | NoSuchFieldException | IllegalAccessException ex){
+            ex.printStackTrace();
+            return false;
+        }
     }
 
     public User findByUsername(String username) {
 
         // TODO:
         // Find a user by username
+        String sql = "SELECT * FROM users WHERE username = ?";
+        try (Connection conn = DatabaseConnection.getConnection(); PreparedStatement stmt = conn.prepareStatement(sql)){
+            stmt.setString(1, username);
+            try (ResultSet rs = stmt.executeQuery()){
+                if (rs.next()){
+                    User user = new User();
+                    Field idField = User.class.getDeclaredField("id");
+                    Field usernameField = User.class.getDeclaredField("username");
+                    Field passwordField = User.class.getDeclaredField("password");
+                    Field emailField = User.class.getDeclaredField("email");
+                    idField.setAccessible(true);
+                    usernameField.setAccessible(true);
+                    passwordField.setAccessible(true);
+                    emailField.setAccessible(true);
+                    idField.set(user, rs.getInt("id"));
+                    usernameField.set(user, rs.getString("username"));
+                    passwordField.set(user, rs.getString("password"));
+                    emailField.set(user, rs.getString("email"));
+                    return user;
+                }
+            }
+        }
+        catch (SQLException | NoSuchFieldException | IllegalAccessException e){
+            e.printStackTrace();
+        }
 
         return null;
     }