Source Code Dasar Java NetBeans untuk Pemula

Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
    int x = (dim.width - getSize().width)/2;
    int y = (dim.height - getSize().height)/2;
    setLocation(x, y);

    String imgUndo=System.getProperty("user.dir")+"\\img\\undo.gif";
    btnUndo.setIcon(new ImageIcon(((new ImageIcon(imgUndo).getImage().getScaledInstance(50, 50,java.awt.Image.SCALE_SMOOTH)))));
    String imgRedo=System.getProperty("user.dir")+"\\img\\redo.gif";
    btnRedo.setIcon(new ImageIcon(((new ImageIcon(imgRedo).getImage().getScaledInstance(50, 50,java.awt.Image.SCALE_SMOOTH)))));
    btnSplash.setIcon(new ImageIcon(((new ImageIcon("img/ic4.png").getImage().getScaledInstance(50, 50,java.awt.Image.SCALE_SMOOTH)))));

=========================================================
>>tanggal :
variabel global
String skrg;

pada initcomponent
                  txtDate.setDateFormatString("yyyy-MM-dd");
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
         skrg=sdf.format(new Date());
            txt_tanggal.setText(skrg);

Pada propertychange
try{
      String tampilan ="yyyy-MM-dd" ;
SimpleDateFormat fm = new SimpleDateFormat(tampilan);
String tanggal = String.valueOf(fm.format(txtDate.getDate()));
    txt_tanggal.setText(tanggal);
       }catch(Exception e){}

if(evt.getKeyCode() == evt.VK_ENTER)
isikodebarang();

    void isikodebarang(){

    String kode=txtKodeBarang.getText().toString();
          try{
          con=kon.open();
          st=con.createStatement();
          query="SELECT * FROM barang where kodebarang like '%"+kode+"%'";
          ResultSet rs=st.executeQuery(query);
          if(rs.next()){
            String kode_barang=rs.getString("kodebarang");
            String nama_barang=rs.getString("namabarang");
            String stok=rs.getString("stok");
            String harga=rs.getString("harga");
            String keterangan=rs.getString("keterangan");
            txtKodeBarang.setText(kode_barang);
            txtNamaBarang.setText(nama_barang);
            txtHarga.setText(harga);
            txtStokBarang.setText(stok);
            txtJumlah.setText("1");
            txtSubTotal.setText(harga);
        }
      }catch(SQLException sqle){}

    }
=========================================================================================================
>>combo Box
String[]ar=new String[1000];
        int n=0;
try {
         con = kon.open();
         st = con.createStatement();
         query = "SELECT * FROM tb_karyawan order by nik asc ";
         ResultSet rs = st.executeQuery(query);
         while (rs.next()) {
            String nik = rs.getString("nik");
            String nama_karyawan = rs.getString("nama_karyawan");
                ar[n]=nik;n++;
         }
}
catch(Exception ee){}
String []ar2=new String[n];
for(int i=0;i<n;i++){
    ar2[i]=ar[i];
}
txtNik.setModel(new javax.swing.DefaultComboBoxModel(ar2));

//Void  lihat
String j=String.valueOf(myTabel.getValueAt(myTabel.getSelectedRow(),1));
      txtNik.setSelectedItem(j);
//get Data
    String kb=txtNik.getSelectedItem().toString();
     String nama_karyawan="";
     String jenis_kelamin="";
     String jabatan="";
     query = "Select * From `tb_karyawan` where `nik` like '"+kb+"'";
         ResultSet rs;
        try {
            rs = st.executeQuery(query);
          if(rs.next()) {
             nama_karyawan = rs.getString("nama_karyawan");
             jenis_kelamin = rs.getString("jenis_kelamin");
             jabatan = rs.getString("jabatan");

            }
        } catch (SQLException ex) {}
         txtNamaKaryawan.setText(nama_karyawan);
            txtJenisKelamin.setText(jenis_kelamin);
            txtJabatan.setText(jabatan);

==========================================================================================================================
>>radio button
String status_masuk = "On Time";
        if(terlambat.isSelected()){
        status_masuk="Terlambat";
        }

void lihat
 String status_masuk=String.valueOf(myTabel.getValueAt(myTabel.getSelectedRow(),2));
        if
                (status_masuk.equalsIgnoreCase("On Time")){On.setSelected(true);}
        else
                 {terlambat.setSelected(true);}
=============================================================================================================================
>>   kode Otomatis
String kode_barang="";
        try{
            con=kon.open();
            st=con.createStatement();
            query="SELECT kode_barang FROM tb_barang order by kode_barang asc";
            ResultSet rs=st.executeQuery(query);
            while(rs.next()){
                kode_barang=rs.getString("kode_barang");
            }
        }
        catch(SQLException sqle)
        {kode_barang="";}
    if (kode_barang.length()<1){kode_barang="BRG000";}
    String ur=kode_barang.substring(3,6);
    int u=Integer.parseInt(ur)+1;
    System.out.println(ur+"=="+u);
    if(u<10){ur="00"+u;}
    else if(u<100){ur="0"+u;}
    else{ur=""+u;}
    kode_barang="BRG"+ur;
    txtkodebarang.setText(kode_barang)
==================================================================================================================================
void Cari(){
String kat=cmbPilih.getSelectedItem().toString();
String item=txtItem.getText();
    removeTable();
      try{
          con=kon.open();
          st=con.createStatement();
          query="SELECT * FROM `tb_barang`  where `"+kat+"` like '%"+item+"%' order by `kode_barang` asc";
          ResultSet rs=st.executeQuery(query);
          while(rs.next()){
            String kode_barang=rs.getString("kode_barang");
            String nama_barang=rs.getString("nama_barang");
            String kode_kategori=rs.getString("kode_kategori");
            String harga=rs.getString("harga");
            String deskripsi=rs.getString("deskripsi");
            String gambar=rs.getString("gambar");
            String status=rs.getString("status");
            String data[]={kode_barang,nama_barang,kode_kategori,harga,deskripsi,gambar,status};
            tabMode.addRow(data);
          }
      }catch(SQLException sqle){
          JOptionPane.showMessageDialog(null,"Data Gagal Masuk Tabel"+sqle);
      }
}
======================================================================================================================================