package net.coderodde.web.db.fun.controllers;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import static net.coderodde.web.db.fun.controllers.DBUtils.close;

/**
 * This controller is responsible for creating new persons.
 *
 * @author Rodion "rodde" Efremov
 * @version 1.6 (Aug 8, 2017)
 */
@WebServlet(name = "AddPersonController", urlPatterns = {"/add_person"})
public class AddPersonController extends HttpServlet {

    /**
     * The SQL command for inserting a person.
     */
    private static final String INSERT_PERSON_SQL =
            "INSERT INTO funny_persons (first_name, last_name, email) VALUES " +
            "(?, ?, ?);";

    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request  the servlet request.
     * @param response the servlet response.
     * @throws ServletException if a servlet-specific error occurs.
     * @throws IOException if an I/O error occurs.
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {
            out.println("Please use the POST method!");
        }
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request  the servlet request.
     * @param response the servlet response.
     * @throws ServletException if a servlet-specific error occurs.
     * @throws IOException if an I/O error occurs.
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");

        try (PrintWriter out = response.getWriter()) {
            String firstName = request.getParameter("first_name");
            String lastName = request.getParameter("last_name");
            String email = request.getParameter("email");

            if (firstName.isEmpty()) {
                out.println("The first name is empty.");
                return;
            }

            if (lastName.isEmpty()) {
                out.println("The last name is empty.");
                return;
            }

            if (email.isEmpty()) {
                out.println("The email is empty.");
                return;
            }

            MysqlDataSource mysql = DefaultDataSourceCreator.create();
            Connection connection = null;
            PreparedStatement statement = null;

            try {
                connection = mysql.getConnection();
                statement = connection.prepareStatement(INSERT_PERSON_SQL);
                statement.setString(1, firstName);
                statement.setString(2, lastName);
                statement.setString(3, email);
                statement.executeUpdate();
            } catch (SQLException ex) {
                out.println("Error: " + ex.getMessage());
            } finally {
                close(null, statement, connection);
            }
        }
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "This servlet adds new persons to the database.";
    }
}

package net.coderodde.web.db.fun.controllers;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import static net.coderodde.web.db.fun.controllers.DBUtils.close;

/**
 * This controller creates the database if it is not yet created.
 *
 * @author Rodion "rodde" Efremov
 * @version 1.6 (Aug 8, 2017)
 */
@WebServlet(name = "CreateDatabaseController", urlPatterns = {"/create"})
public class CreateDatabaseController extends HttpServlet {

    /**
     * Creates a new database if not already created.
     */
    private static final String CREATE_DATABASE_SQL =
            "CREATE DATABASE IF NOT EXISTS funny_db;";

    /**
     * Switches to 'funny_db'.
     */
    private static final String USE_DATABASE_SQL = "USE funny_db";

    /**
     * Creates the table if not already created.
     */
    private static final String CREATE_TABLE_SQL =
            "CREATE TABLE IF NOT EXISTS funny_persons (n" +
                "id INT(6) UNSIGNED AUTO_INCREMENT PRIMARY KEY,n" +
                "first_name VARCHAR(40) NOT NULL,n" +
                "last_name VARCHAR(40) NOT NULL,n" +
                "email VARCHAR(50) NOT NULL,n" +
                "created TIMESTAMP);";

    /**
     * If not yet created, this request creates the database and the table.
     *
     * @param request  the servlet request.
     * @param response the servlet response.
     * @throws ServletException if a servlet-specific error occurs.
     * @throws IOException if an I/O error occurs.
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");

        try (PrintWriter out = response.getWriter()) {
            MysqlDataSource mysql = DefaultDataSourceCreator.create();
            Connection connection = null;
            PreparedStatement statement = null;
            boolean error = false;

            try {
                connection = mysql.getConnection();
                statement = connection.prepareStatement(CREATE_DATABASE_SQL);
                statement.execute();

                statement = connection.prepareStatement(USE_DATABASE_SQL);
                statement.execute();

                statement = connection.prepareStatement(CREATE_TABLE_SQL);
                statement.execute();
            } catch (SQLException ex) {
                error = true;
                out.println("Error: " + ex.getMessage());
            } finally {
                close(null, statement, connection);
            }

            if (!error) {
                out.println("Database 'funny_db' is created!");
            }
        }
    }

    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request  the servlet request.
     * @param response the servlet response.
     * @throws ServletException if a servlet-specific error occurs.
     * @throws IOException if an I/O error occurs.
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request  the servlet request.
     * @param response the servlet response.
     * @throws ServletException if a servlet-specific error occurs.
     * @throws IOException if an I/O error occurs.
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description.
     */
    @Override
    public String getServletInfo() {
        return "Creates the database and the table.";
    }
}

package net.coderodde.web.db.fun.controllers;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

/**
 * This class contains some common utilities for dealing with databases.
 *
 * @author Rodion "rodde" Efremov
 * @version 1.6 (Aug 8, 2017)
 */
public final class DBUtils {

    /**
     * Creates and sets a MySQL data source.
     *
     * @param user       the user name.
     * @param password   the password.
     * @param url        the database URL.
     * @param port       the database port.
     * @param serverName the name of the server.
     *
     * @return the MySQL data source.
     */
    public static  MysqlDataSource getMysqlDataSource(String user,
                                                      String password,
                                                      String url,
                                                      int port,
                                                      String serverName) {
        MysqlDataSource dataSource = new MysqlDataSource();

        if (user != null) {
            dataSource.setUser(user);
        }

        if (password != null) {
            dataSource.setPassword(password);
        }

        if (url != null) {
            dataSource.setURL(url);
        }

        if (port >= 0) {
            dataSource.setPort(port);
        }

        if (serverName != null) {
            dataSource.setServerName(serverName);
        }

        return dataSource;
    }

    /**
     * Closes a {@code ResultSet}.
     *
     * @param resultSet the result set to close.
     */
    public static void close(ResultSet resultSet) {
        try {
            if (resultSet != null) {
                resultSet.close();
            }
        } catch (SQLException ex) {
            throw new RuntimeException("Could not close a ResultSet.", ex);
        }
    }

    /**
     * Closes a {@code PreparedStatement}.
     *
     * @param preparedStatement the prepared statement to close.
     */
    public static void close(PreparedStatement preparedStatement) {
        try {
            if (preparedStatement != null) {
                preparedStatement.close();
            }
        } catch (SQLException ex) {
            throw new RuntimeException(
                    "Could not close a PreparedStatement.",
                    ex);
        }
    }

    /**
     * Closes a {@code Connection}.
     *
     * @param connection the connection to close.
     */
    public static void close(Connection connection) {
        try {
            if (connection != null) {
                connection.close();
            }
        } catch (SQLException ex) {
            throw new RuntimeException(
                    "Could not close a Connection.",
                    ex);
        }
    }

    /**
     * Closes the data base related resources.
     *
     * @param resultSet         the result set to close.
     * @param preparedStatement the prepared statement to close.
     * @param connection        the connection to close.
     */
    public static void close(ResultSet resultSet,
                             PreparedStatement preparedStatement,
                             Connection connection) {
        close(resultSet);
        close(preparedStatement);
        close(connection);
    }
}

package net.coderodde.web.db.fun.controllers;

import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;

public class DefaultDataSourceCreator {

    public static MysqlDataSource create() {
        MysqlDataSource mysql =
                DBUtils.getMysqlDataSource(
                        "root",
                        "your_password",
                        "jdbc:mysql://localhost:3306/funny_db",
                        -1,
                        null);

        return mysql;
    }
}

package net.coderodde.web.db.fun.controllers;

import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class MyFilter implements javax.servlet.Filter {

    private final int id;
    private final String firstName;

    public MyFilter(int id, String firstName) {
        this.id = id;
        this.firstName = firstName;
    }

    @Override
    public void init(FilterConfig filterConfig)
            throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request,
            ServletResponse response,
            FilterChain chain)
            throws IOException, ServletException {
        ((HttpServletResponse) response)
                .sendRedirect("/DBWebFun/show/" + id + "/" + firstName);
    }

    @Override
    public void destroy() {

    }
}

package net.coderodde.web.db.fun.controllers;

import com.google.gson.Gson;
import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.coderodde.web.db.fun.model.FunnyPerson;

import static net.coderodde.web.db.fun.controllers.DBUtils.close;

/**
 * This controller is responsible for viewing persons.
 *
 * @author Rodion "rodde" Efremov
 * @version 1.6 (Aug 8, 2017)
 */
@WebServlet(name = "ShowPersonController", urlPatterns = {"/show/*"})
public class ShowPersonController extends HttpServlet {

    private static final String GET_USER_BY_ID_SQL =
            "SELECT * FROM funny_persons WHERE id = ?;";

    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code>
     * methods.
     *
     * @param request  the servlet request.
     * @param response the servlet response.
     * @throws ServletException if a servlet-specific error occurs.
     * @throws IOException if an I/O error occurs.
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");

        try (PrintWriter out = response.getWriter()) {
            MysqlDataSource mysql = DefaultDataSourceCreator.create();
            String path = request.getPathInfo();

            if (path.startsWith("/")) {
                path = path.substring(1);
            }

            String[] tokens = path.split("/");

            if (tokens.length == 0) {
                out.println("At least the user ID is required.");
                return;
            }

            String idString = tokens[0];
            int id = -1;

            try {
                id = Integer.parseInt(idString);
            } catch (NumberFormatException ex) {
                out.println(idString + ": not an integer.");
                return;
            }

            FunnyPerson person = new FunnyPerson();

            Connection connection = null;
            PreparedStatement statement = null;
            ResultSet resultSet = null;

            try {
                connection = mysql.getConnection();
                statement = connection.prepareStatement(GET_USER_BY_ID_SQL);
                statement.setInt(1, id);
                resultSet = statement.executeQuery();

                if (!resultSet.next()) {
                    close(resultSet, statement, connection);
                    out.println("{"status": "error"}");
                    return;
                }

                String matchFirstName = null;

                if (tokens.length == 2) {
                    matchFirstName = tokens[1];
                }

                if (!matchFirstName.equals(resultSet.getString("first_name"))) {
                    MyFilter myFilter =
                            new MyFilter(id, resultSet.getString("first_name"));

                    myFilter.doFilter(request, response, null);
                    return;
                }

                person.setId(resultSet.getInt("id"));
                person.setFirstName(resultSet.getString("first_name"));
                person.setLastName(resultSet.getString("last_name"));
                person.setEmail(resultSet.getString("email"));
                person.setCreated(resultSet.getDate("created"));

                Gson gson = new Gson();
                out.println(gson.toJson(person));
            } catch (SQLException ex) {
                throw new RuntimeException("SQLException thrown.", ex);
            } finally {
                close(resultSet, statement, connection);
            }
        }
    }

    private void handleInvalidRequest(HttpServletRequest request,
                                      HttpServletResponse response) {

    }

    /**
     * Handles the HTTP <code>GET</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     *
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     *
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Shows the user info via ID/first_name";
    }
}

package net.coderodde.web.db.fun.model;

import java.sql.Date;

public final class FunnyPerson {

    private int id;
    private String firstName;
    private String lastName;
    private String email;
    private Date created;

    public int getId() {
        return id;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public String getEmail() {
        return email;
    }

    public Date getCreated() {
        return created;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public void setCreated(Date created) {
        this.created = created;
    }
}