新・Servlet/JSP入門編7: データベースとの連携について学習しよう

【LoginModel】

package jp.paiza.model;

import jp.paiza.bean.AccountBean;
import java.sql.*;

public class LoginModel {
    
    private Connection con;
    
    public LoginModel(Connection con) {
        this.con = con;
    }
    
    public boolean login(String userId, String password) {
        
        String sql = "select * from accounts where user_id = ? and password = ?";
        
        try (PreparedStatement query = con.prepareStatement(sql)) {
            query.setString(1, userId);
            query.setString(2, password);
            ResultSet rs = query.executeQuery();
            boolean b = rs.next();
            System.out.println(b);
            return b;
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
    
    public AccountBean find(String userId) throws SQLException {

        String sql = "select * from accounts where user_id = ?";
  
        try (PreparedStatement query = con.prepareStatement(sql)) {
            query.setString(1, userId);
            ResultSet rs = query.executeQuery();
            if (rs.next()) {
                AccountBean account = new AccountBean();
                account.setId(rs.getInt("id"));
                account.setUserId(rs.getString("user_id"));
                account.setCreatedAt(rs.getTimestamp("created_at"));
                account.setUpdatedAt(rs.getTimestamp("updated_at"));
                return account;
            }
        } 
        throw new SQLException("userが存在しない");
    }
}

新・Java入門編36: JDBCについて学習しよう
https://paiza.jp/works/java/new-primer/java-new-primer-36

新・SQL入門編2: SELECT文を理解しよう
https://paiza.jp/works/sql/new-primer/sql-new-primer-2

新・Java入門編27: 例外について学習しよう
https://paiza.jp/works/java/new-primer/java-new-primer-27

インタフェースDataSource
https://docs.oracle.com/javase/jp/17/docs/api/java.sql/javax/sql/DataSource.html

インタフェースPreparedStatement
https://docs.oracle.com/javase/jp/17/docs/api/java.sql/java/sql/PreparedStatement.html

インタフェースResultSet
https://docs.oracle.com/javase/jp/17/docs/api/java.sql/java/sql/ResultSet.html