feat : implement restaurant management system

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

@@ -1,23 +1,60 @@
 package dev.dao;
 
+import dev.database.DatabaseConnection;
 import dev.model.User;
+import java.sql.*;
 
-public class UserDao {
+public class UserDao
+{
+    public boolean save(User user)
+    {
+        String sql = "INSERT INTO users(username,password,email) VALUES(?,?,?)";
 
-    public boolean save(User user) {
+        try(Connection connection = DatabaseConnection.getConnection();
+            PreparedStatement ps = connection.prepareStatement(sql))
+        {
+            ps.setString(1,user.getUsername());
+            ps.setString(2,user.getPassword());
+            ps.setString(3,user.getEmail());
 
-        // TODO:
-        // Insert user into database
-
-        return false;
+            return ps.executeUpdate() > 0;
+        }
+        catch (SQLException e)
+        {
+            e.printStackTrace();
+            return false;
+        }
     }
 
-    public User findByUsername(String username) {
+    public User findByUsername(String username)
+    {
+        String sql = "SELECT * FROM users WHERE username=?";
 
-        // TODO:
-        // Find a user by username
+        try(Connection connection = DatabaseConnection.getConnection();
+            PreparedStatement ps = connection.prepareStatement(sql))
+        {
+            ps.setString(1,username);
+
+            ResultSet rs = ps.executeQuery();
+
+            if(rs.next())
+            {
+                User user = new User();
+
+                user.setId(rs.getInt("id"));
+                user.setUsername(rs.getString("username"));
+                user.setPassword(rs.getString("password"));
+                user.setEmail(rs.getString("email"));
+
+                return user;
+            }
+
+        }
+        catch (SQLException e)
+        {
+            e.printStackTrace();
+        }
 
         return null;
     }
-
 }