[Java] Urejanje baze z JTable

Kar se tiče dela z bazo sem napisal sledeče, ki izpiše celotno (izbrano) tabelo v bazi v JTable. V
V JComboBox-u izberem ime tabele (z poizvedbo dobim imena tabel- ni v tem odseku kode) nato JTable napolnimo.

private void jComboBox_imenaTabelItemStateChanged(java.awt.event.ItemEvent evt) {                                                      
        System.out.println("Sem v comboBox-u");
        Statement statement;
        String query;
        ResultSet rs;
        int stolpec;
        tabela = jTable_PodBaza;
        ResultSetMetaData rsm;
        

        try {

            Object obj = jComboBox_imenaTabel.getSelectedItem();
            String izbrano = obj.toString();
           
            qtm = new QueryTableModel();
            tabela.setModel(qtm);
            qtm.setHostURL("jdbc:mysql://localhost:3306/chat");
            qtm.setQuery("select * from " + izbrano);     
       
        } catch (Exception e) {
            e.printStackTrace();
        }
    }     

QueryTableModel je class, ki deduje AbstractTableModel. Tukej se izvede poizvedba in napolni tabelo:
Sem malenkost spremenil že napisan source :)

import java.awt.*;
import java.sql.*;
import java.util.*;
import java.util.logging.Logger;
import javax.swing.*;
import javax.swing.table.*;

class QueryTableModel extends AbstractTableModel {
  Vector cache; // will hold String[] objects . . .
  Vector cache2;

  int colCount;

  String[] headers;

  Connection db;

  Statement statement;

  String currentURL;

    
  public QueryTableModel() {
    cache = new Vector();
    cache2 = new  Vector();
    new Driver() {

            @Override
            public Connection connect(String url, Properties info) throws SQLException {
                throw new UnsupportedOperationException("Not supported yet.");
            }

            @Override
            public boolean acceptsURL(String url) throws SQLException {
                throw new UnsupportedOperationException("Not supported yet.");
            }

            @Override
            public DriverPropertyInfo[] getPropertyInfo(String url, Properties info) throws SQLException {
                throw new UnsupportedOperationException("Not supported yet.");
            }

            @Override
            public int getMajorVersion() {
                throw new UnsupportedOperationException("Not supported yet.");
            }

            @Override
            public int getMinorVersion() {
                throw new UnsupportedOperationException("Not supported yet.");
            }

            @Override
            public boolean jdbcCompliant() {
                throw new UnsupportedOperationException("Not supported yet.");
            }

            @Override
            public Logger getParentLogger() throws SQLFeatureNotSupportedException {
                throw new UnsupportedOperationException("Not supported yet.");
            }
        };
  }
 public void addEmptyRow () {
String[] rowData = new String[colCount] ;
for(int i=0;i< colCount;i++)
rowData[i] = "" ;
cache.addElement(rowData);
System.out.println("vector:" +cache.size());
fireTableChanged(null); 
 }
 public void addEmptyRow2 (String upIme,String ip, int port) {
     try {
 Vector ram = new Vector();
String[] rowData2 = {upIme,ip,Integer.toString(port)} ;
ram.add(rowData2);
cache2.addElement(rowData2);
fireTableChanged(null);

System.out.println("velikost vector2: "+cache2.size());
System.out.println("vector2: "+cache2.get(0).toString());
     }
     catch (Exception e){e.printStackTrace();}
 
 }
 public boolean isCellEditable(int row, int col)  
        { return true; }  

  public String getColumnName(int i) {
    return headers[i];
  }

  public int getColumnCount() {
    return colCount;
  }

  public int getRowCount() {
    return cache.size();
  }

  public Object getValueAt(int row, int col) {
    return ((String[]) cache.elementAt(row))[col];
  }

  public void setHostURL(String url) {
    if (url.equals(currentURL)) {
      // same database, we can leave the current connection open
      return;
    }
    // Oops . . . new connection required
    closeDB();
    initDB(url);
    currentURL = url;
  }

  // All the real work happens here; in a real application,
  // we'd probably perform the query in a separate thread.
  public void setQuery(String q) {
    cache = new Vector();
    try {
     // izvede se poizvedba in iz nje (preko metaData) dobimo stevilo stolpcev. 
      ResultSet rs = statement.executeQuery(q);
      ResultSetMetaData meta = rs.getMetaData();
      colCount = meta.getColumnCount();

      // Now we must rebuild the headers array with the new column names
      headers = new String[colCount];
      for (int h = 1; h <= colCount; h++) {
        headers[h - 1] = meta.getColumnName(h);
      }

      // and file the cache with the records from our query. This would
      // not be
      // practical if we were expecting a few million records in response
      // to our
      // query, but we aren't, so we can do this.
      while (rs.next()) {
        String[] record = new String[colCount];
        for (int i = 0; i < colCount; i++) {
          record[i] = rs.getString(i + 1);
        }
        cache.addElement(record);
      }
      fireTableChanged(null); // notify everyone that we have a new table.
    } catch (Exception e) {
      cache = new Vector(); // blank it out and keep going.
      e.printStackTrace();
    }
  }

  public void initDB(String url) {
    try {
      db = DriverManager.getConnection(url,"root","");
      statement = db.createStatement();
    } catch (Exception e) {
      System.out.println("Could not initialize the database.");
      e.printStackTrace();
    }
  }

  public void closeDB() {
    try {
      if (statement != null) {
        statement.close();
      }
      if (db != null) {
        db.close();
      }
    } catch (Exception e) {
      System.out.println("Could not close the current connection.");
      e.printStackTrace();
    }
  }
}

Sedaj me zanima kako "poslušat" JTable. Ob morebitni spremembi(spreminanje vrednosti v celici, dodajanje vrstice, izbris vrstice)bi posodobil bazo oz. tabelo (ko uporabnik pritisne na gumb). Sicer sem že precej poizvedoval po googlu ampak nisem dobil potrebnih informacij. Pišem pa chat aplikacijo (server in client) - končujem . Zelo bi bil hvaležen vsakršne pomoči. Hvala

JTable kontrola je ena izmed kompleksnejših. Za prikaz polj uporablja cell render(mogoče tudi painter) za urejanje polja pa cell editor.
Cell editor se registrira na JTable za posamezen podatkovni tip in ob urejanju celice JTable potem kliče CellEditor za pridobitev kontrole za urejanje. Po končanem urejanju kliče CellEditor za obdelavo vnesešene vrednosti.

Več pa si lahko na internetu najdeš:
http://docs.oracle.com/javase/1.4.2/doc...
http://www.exampledepot.com/egs/javax.s...

Shranjevanje boš moral opraviti v celoti v celleditorju.
v metodi getTableCellEditorComponent() si shrani številko vrstice in stolpca in kar potrebuješ, to potem uporabi v getCellEditorValue(). Ime stolpca dobiš preko TableModel-a z metodo getColumnName().

http://docs.oracle.com/javase/1.4.2/doc...

Osveževanje je zelo problematično.
Osvežiš načeloma s setModel(), vendar ima ta metoda en pogoj, ki ne osveži tabele, če ima TableModel enako referenco, tako ne moreš klicati table.setModel(getModel()).
Da je zadeva hujša ne dovoli null vrednosti, zato ne moreš napisati:
table.setModel(null); table.setModel(prejsniModel);

Tako, da moraš razširiti JTable in prekriti to metodo(pobrano iz izvorne kode jave):

JTable table = new JTable(){
 @Override public void setModel(TableModel dataModel) {
        if (dataModel == null) {
            throw new IllegalArgumentException("Cannot set a null TableModel");
        }
       // if (this.dataModel != dataModel) {
            TableModel old = this.dataModel;
            if (old != null) {
                old.removeTableModelListener(this);
            }
            this.dataModel = dataModel;
            dataModel.addTableModelListener(this);

            tableChanged(new TableModelEvent(dataModel, TableModelEvent.HEADER_ROW));

            firePropertyChange("model", old, dataModel);

            if (getAutoCreateRowSorter()) {
                setRowSorter(new TableRowSorter<TableModel>(dataModel));
            }
      //  }
    }
};

Ja, ko posodobiš vrednosti v podatkih, moraš posodobiti tudi JTable.
To pa lahko narediš z setModel metodo.