jdbcConn.java

public class DatabaseTest {

  private Connection koneksi;
  String host;
  String user;
  String pass;

//konstruktor, saat object tercipta langsung membuat koneksi ke database
public DatabaseTest() {
    host = "jdbc:mysql://localhost/pos"; //jdbc:mysql://localhost/databaseName
    user = "alka"; // username in database server "root" is default
    pass = "alka"; // password in database server
    try {

       if (cekDriver()) { //jika cekDriver==true
        koneksi = DriverManager.getConnection(host, user, pass); /*object dari koneksi yang akan mengurusi koneksi ke database*/
        System.out.println("connection to database established");
      }
    } catch (SQLException e) {
      System.out.println("Connection failed " + e.getMessage());
    }
  }

//method untuk mengecek apakah Driver untuk koneksi ke database sudah ada atau belum
  public final boolean cekDriver() {
    boolean ada = false;
    try {
      Class.forName("com.mysql.jdbc.Driver"); //di cek is driver exist ?
      System.out.println("Driver oke");
      ada = true;
    } catch (ClassNotFoundException c) {
      System.out.println("Driver tidak ada");
    }
    return ada; //kembalikan keterangan apakah driver ada atau tidak
  }

  public void cetakSemuaPerson() {
    String sql = "select * from t_person";
    try {
      Statement st = koneksi.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);

      //object dari resultset menampung hasilnya
      ResultSet rs = st.executeQuery(sql);
      System.out.println("id    name       password");
      System.out.println("-------------------------");

      //selama masih ada data (next)
      while (rs.next()) {
        int id = rs.getInt(1);
        String name = rs.getString(2);
        String pwd = rs.getString(3);
        System.out.printf("%-4d  %10s  %10s \n", id, name, pwd);
      }
    } catch (SQLException ex) {
      System.out.println(ex.getMessage());
    }
  }

  public void cetakPerson(int id) {
    String sql = "select * from t_person where id ='" + id + "'";
    try {
      Statement st = koneksi.createStatement();
      ResultSet rs = st.executeQuery(sql);
      while (rs.next()) {
        String name = rs.getString(2);
        String pwd = rs.getString(3);
        System.out.println(id + " " + name + " " + pwd);
      }
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public boolean tambahPerson(String name, String psw) {
    boolean result = false;
    String sql = "insert into t_person(name,password) values('" + name + "','" + psw + "')";
    try {
      Statement st = koneksi.createStatement();
      st.executeUpdate(sql);
      result = true;
      System.out.println("data berhasil dimasukkan");
    } catch (Exception e) {
      System.out.println("gagal insert data " + e.getMessage());
    }
    return result;
  }

  public void hapusPerson(String nama){
  int hasil=0;
  String sql="delete from t_person where name='"+nama+"'";
  try{
    Statement st = koneksi.createStatement();
    hasil = st.executeUpdate(sql);
  }catch(SQLException e){
    System.out.println("tidak bisa hapus data "+e.getMessage());
  }
    System.out.println((hasil==1)?"berhasil hapus data":"gagal hapus data");
  }

  public void updateNamaPerson(int id,String namaBaru){
  int hasil=0;
  String sql = "update t_person set name='"+namaBaru+"' where id='"+id+"'";
    try {
      Statement st = koneksi.createStatement();
      hasil = st.executeUpdate(sql);
    } catch (SQLException e) {
      System.out.println(e.getMessage());
    }

    System.out.println((hasil==1)?"update berhasil":"update gagal");
  }

  public void updatePassword(int id, String passBaru){
    int hasil=0; //untuk menampung hasil dari method executeUpdate, jika nol maka gagal jika 1 makan makan
  String sql = "update t_person set password='"+passBaru+"' where id='"+id+"'";
    try {
      Statement st = koneksi.createStatement();
      hasil = st.executeUpdate(sql);
    } catch (SQLException e) {
      System.out.println(e.getMessage());
    }

    System.out.println((hasil==1)?"update berhasil":"update gagal");
  }

  //tinggal dihapus aja kode komenya kalo pengen coba
  public static void main(String[] args) {
    //DatabaseTest db = new DatabaseTest();
    //db.tambahPerson("wero", "alka");
    //db.updateNamaPerson(1, "ayuDewi");
    //db.updatePassword(1, "passBaru");
    //db.cetakSemuaPerson();
   // db.hapusPerson("wero");
  }
}