implement UserDao.java

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

@@ -1,23 +1,63 @@
 package dev.dao;
 
+import dev.database.DatabaseConnection;
 import dev.model.User;
 
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
 public class UserDao {
 
     public boolean save(User user) {
 
-        // TODO:
         // Insert user into database
 
-        return false;
+        String sql = "INSERT INTO users (username, password, email) VALUES(?, ?, ?)";
+
+        try(Connection connection = DatabaseConnection.getConnection();
+            PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+
+            preparedStatement.setString(1, user.getUsername());
+            preparedStatement.setString(2, user.getPassword());
+            preparedStatement.setString(3, user.getEmail());
+
+            return preparedStatement.executeUpdate() > 0;
+
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     public User findByUsername(String username) {
 
-        // TODO:
         // Find a user by username
+        // Retrieve all orders of a user
+        String sql = "SELECT * FROM users WHERE username=?";
 
+        try (Connection connection = DatabaseConnection.getConnection();
+             PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
+
+            preparedStatement.setString(1, username);
+
+            ResultSet resultSet = preparedStatement.executeQuery();
+
+            if (resultSet.next()) {
+
+                User user = new User();
+
+                user.setId(resultSet.getInt("id"));
+                user.setUsername(resultSet.getString("username"));
+                user.setPassword(resultSet.getString("password"));
+                user.setEmail(resultSet.getString("email"));
+
+                return user;
+            }
+
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
         return null;
     }
-
 }