jTable - how to show only show limited columns? Java - java

This is the code for the "creation" of the table I have in my DataAccessLayer.
private TableModel getResultSetAsDefaultTableModel(ResultSet rs) {
try {
String[] columnHeadings = new String[0];
Object[][] dataArray = new Object[0][0];
ResultSetMetaData md = rs.getMetaData();
int columnCount = md.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
String columnName = md.getColumnName(i);
columnHeadings = Arrays.copyOf(columnHeadings, columnHeadings.length + 1);
columnHeadings[i - 1] = columnName;
}
int r = 0;
while (rs.next()) {
Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; i++) {
row[i - 1] = rs.getObject(i);
}
dataArray = Arrays.copyOf(dataArray, dataArray.length + 1);
dataArray[r] = row;
r++;
}
DefaultTableModel dtm = new DefaultTableModel(dataArray, columnHeadings) {
public boolean isCellEditable(int row, int column) {
return false;
}
};
return dtm;
} catch (SQLException ex) {
Logger.getLogger(Dataaccesslayer.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
**This results in some complications, since one of my tables has 50 different columns and therefore you can't read the columnnames or what is in the cell.
The problem is that the table's values are determined by the metadata...
I want to limit the columns that are showed to a specific number (5) for all tables.
How do I do it?**
Kind regards,
Chris

you can remove tables if you want to...
int amountColumns = table.getColumnModel().getColumnCount(); //count columns
TableColumn c6 = table.getColumnModel().getColumn(6); //identif a random column
table.getColumnModel().removeColumn(c6); //remove this column
i hope that helped...

I would not remove them but change their size to 0.
int amountColumns = table.getColumnModel().getColumnCount(); //count columns
TableColumn c6 = table.getColumnModel().getColumn(6); //identif a random column
table.getColumnModel().setMin(0);
table.getColumnModel().setMax(0);
table.getColumnModel().setPreferredWidth(0);
Like i answered you in your other thread...

Related

Updating a JPanel of queried results from a database

When a user clicks a button initially, a query is run and each row is put into a JPanel and added to the display for the user to view. Which works fine.
My problem is, I want the user to be able to filter these results according to values that they provide ( through a JTextField ) , and I want the displayed records to update as the value of the JTextField changes. My queries are formed and executed each time the JTextField is changed, but I can't find a way to update the records displayed.
Any help would be appreciated.
The code took a while to edit to the satisfaction of stackoverflow, but here it is. Hopefully you can follow the logic. This is the method that deals with formation and execution of the queries, which works(again).
The problem is displaying the new results.
private void processSearch(){
int count = 0;
double width;
remove(allInfo);
allInfo = new JPanel();
allInfo.setLayout(new GridLayout(0, 1, 5, 10));
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
width = screenSize.getWidth();
try {
DatabaseConnetor connect = new DatabaseConnetor();
Connection conn = connect.connect();
String query = "";
String whereClause = "";
int unEmpty = 0;
String [] searches ={searchNameTxt.getText(), searchMailTxt.getText(), searchContactTxt.getText(), (String) searchGender.getSelectedItem()};
String [][] keys = {{"first_name", "middle_name", "family_name", "surname"}, {"email"}, {"contact", "contact2"}, {"gender"}};
for(int i=0; i < searches.length; i++){
if(!searches[i].trim().isEmpty()){
unEmpty++;
}
for(int i=0; i < searches.length; i++){
int counter = 0;
if(!searches[i].trim().isEmpty()){
whereClause += " AND ";
int len = keys[i].length;
if(len == 1){
whereClause += " ("+keys[i][0]+" LIKE '%"+searches[i]+"%') ";
}else if(len > 1){
whereClause += " ( ";
while(counter < len){
if(counter == len-1)
whereClause += keys[i][counter]+" LIKE '%"+searches[i]+"%'";
else
whereClause += keys[i][counter]+" LIKE '%"+searches[i]+"%' OR ";
counter++;
}
whereClause += " ) ";
}
}
}
query = "SELECT photo, first_name, middle_name, family_name, surname, gender, email, contact, contact2 FROM user WHERE rights = 2" + whereClause;
PreparedStatement preparedStatement = conn.prepareStatement(query);
String gen = "", middle = "", family = "", cont = "", phot = "";
ResultSet result = preparedStatement.executeQuery();
while(result.next()){
JPanel data = new JPanel();
data.setPreferredSize(new Dimension((int)(width*0.75), 50));
data.setLayout(new GridLayout(1, 0, 5, 10));
if(result.getString(1) == "NULL")
phot = "";
data.add(new JLabel(phot)); //Photo
data.add(new JLabel(result.getString(2))); //First Name
if(result.getString(3) == "NULL")
middle = "";
data.add(new JLabel(middle)); //Middle Name
if(result.getString(4) == "NULL")
family = "";
data.add(new JLabel(family)); //Family Name
data.add(new JLabel(result.getString(5))); //Surname
if(result.getString(6).equals("M"))
gen = "Male";
else
gen = "Female";
data.add(new JLabel(gen)); //Gender
data.add(new JLabel(result.getString(7))); //E-Mail
data.add(new JLabel(result.getString(8))); //Contact1
if(result.getString(9) == "NULL")
cont = "";
data.add(new JLabel(cont)); //Contact 2
allInfo.add(data);
}
add(allInfo);
connect.disconnect(conn);
connect = null;
conn = null;
} catch (SQLException e1) {
e1.printStackTrace();
}
}
}
a query is run and each row is put into a JPanel and added to the display for the user to view
I would suggest you use a JTable to display the data from a database. A JTable is designed to display data in a row/column format.
Read the section from the Swing tutorial on How to Use Tables for more information and examples.
I want the user to be able to filter these results according to values that they provide ( through a JTextField ) , and I want the displayed records to update as the value of the JTextField changes.
A JTable supports dynamic filtering of the data displayed in the table. The above tutorial has a section on Sorting and Filtering that shows how to filter as text is entered into a text field. Filtering the table is more efficient then redoing the SQL query.
Adding data to the table is straight forward. Instead of creating a panel with each column of data you can add a new row of data to the TableModel:
String sql = "Select * from ???";
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.addElement( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
Vector<Object> row = new Vector<Object>(columns);
for (int i = 1; i <= columns; i++)
{
row.addElement( rs.getObject(i) );
}
data.addElement( row );
}
// Create table with database data
DefaultTableModel model = new DefaultTableModel(data, columnNames)
{
#Override
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
JTable table = new JTable( model );
JScrollPane scrollPane = new JScrollPane( table );

How to give Column Name to ResultSet dynamically in this case?

I have an ArrayList as shown below
import java.util.ArrayList;
public class Mann {
public static void main(String args[]) {
ArrayList<String> billOrderList = new ArrayList<String>();
list.add("VAT");
list.add("Discount");
list.add("SERVICE CHARGE");
StringBuilder select_query = new StringBuilder();
select_query.append("Select ");
for (int i = 0; i < billOrderList.size(); i++) {
if (i != billOrderList.size() - 1) {
select_query.append("" + billOrderList.get(i) + " , ");
} else {
select_query.append("" + billOrderList.get(i) + "");
}
}
select_query.append(" From VENDOR_ITEMS WHERE vendor_items_id = "
+ vendor_item + "");
VendorItems_Pstmt = dbConnection.prepareStatement(select_query
.toString());
VendorItems_RSet = VendorItems_Pstmt.executeQuery();
while (VendorItems_RSet.next()) {
String tax_name = VendorItems_RSet.getString();
}
}
}
How can i give the column name which is dynamic in this case in line VendorItems_RSet.getString();??
You need as ResultSetMetaData to get the column name associated with your query result.
You can get ResultSetMetaData from ResultSet by using ResultSet.getMetaDate, you can iterate it and get column all column name.
ResultSetMetaData VendorItems_RSet_metaData = VendorItems_RSet.getMetaData();
int numberOfColumns = VendorItems_RSet_metaData .getColumnCount();
for(int i=1;i<=numberOfColumns;i++)
{
String columnName = VendorItems_RSet_metaData.getColumnName(i);
}
I think you need all column data for that you can iterate your loop like
while (VendorItems_RSet.next())
{
for(int i=1;i<=numberOfColumns;i++)
{
String columnName = VendorItems_RSet_metaData.getColumnName(i);
String tax_name = VendorItems_RSet.getString(columnName);
System.out.println(tax_name);
}
}
ResultSetMetaData resultSetMetaData = VendorItems_RSet.getMetaData();
for (int i = 1; i <= resultSetMetaData.getColumnCount(); i++) {
String type = resultSetMetaData.getColumnTypeName(i); // Get Column type
String name= resultSetMetaData.getColumnName(i); //Column name
}
}
SELECT * and then
ResultSetMetaData metaData = VendorItems_RSet.getMetaData();
int columns = metaData.getColumnCount();
for (int i = 1; i <= columns; ++i) {
System.out.println(metaData.getColumnName(1));
}

Insert data to MySQL table from JTable in Java GUI

I've made a GUI in Java that connects with a MySQL server and inserts,deletes,updates data. I have a section on this GUI that you can write in a text area a MySQL query and the result is displayed on a Jtable. Everything works fine! I can print the data from the JTable or save them to a text file!
Now, I want to add another feature: When I double click on a specific cell, I would like to change the data of the JTable, and I want this data to be updated in the MySQL table with the click of a button as well.
I've searched all over the internet, but I can't find a good example or a good solution. The JTable I have is dynamic; that means that what ever query is inserted the data will be displayed with the quired column names and data
Here is the code:
ArrayList columnNames = new ArrayList();
ArrayList data = new ArrayList();
data_connector getdata1 = new data_connector();
host = getdata1.getHost();
username = getdata1.getUsername();
password1 = getdata1.getPassword();
mysql_command = getdata1.getMysql_command();
command_name = getdata1.getCommand_name();
setTitle(command_name);
// Connect to an MySQL Database, run query, get result set
String url = "jdbc:mysql://"+host+":3306/xxxxx";
String userid = username;
String password = password1;
String sql = mysql_command;
// Java SE 7 has try-with-resources
// This will ensure that the sql objects are closed when the program
// is finished with them
try (Connection connection = DriverManager.getConnection( url, userid, password );
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery( sql ))
{
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
columnNames.add(md.getColumnName(i));
// Get row data
while (rs.next())
{
ArrayList row = new ArrayList(columns);
for (int i = 1; i <= columns; i++)
row.add(rs.getObject(i));
data.add(row);
}
}
catch (SQLException e)
{
System.out.println(e.getMessage());
JOptionPane.showMessageDialog(null, e.getMessage());
mysql_fail_flag = 1;
}
// Create Vectors and copy over elements from ArrayLists to them
// Vector is deprecated but I am using them in this example to keep
// things simple - the best practice would be to create a custom defined
// class which inherits from the AbstractTableModel class
Vector columnNamesVector = new Vector();
Vector dataVector = new Vector();
for (int i = 0; i < data.size(); i++)
{
ArrayList subArray = (ArrayList)data.get(i);
Vector subVector = new Vector();
for (int j = 0; j < subArray.size(); j++)
subVector.add(subArray.get(j));
dataVector.add(subVector);
}
for (int i = 0; i < columnNames.size(); i++ )
columnNamesVector.add(columnNames.get(i));
contentPane.setLayout(null);
// Create table with database data
table = new JTable(dataVector, columnNamesVector)
{
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
return o.getClass();
}
return Object.class;
}
};
// table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
JScrollPane scrollPane = new JScrollPane(table);
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setBounds(5, 5, xframeWidth-20, yframeHeight-70);
getContentPane().add(scrollPane);
JPanel buttonPanel = new JPanel();
buttonPanel.setBounds(5, 856, 1574, 1);
getContentPane().add(buttonPanel);
buttonPanel.setLayout(null);
In the form you actually create your JTable, I don't think this is easy. What you want to do is subclassing AbstractTableModel, and overwrite the setValueAt() method. You subclass could look like this:
class MyModel extends AbstractTableModel
{
private ResultSet result;
private ResultSetMetaData metadata;
public MyModel (ResultSet rs)
{
super();
result = rs; // mustn't be null, maybe check and throw NPE
metadata = result.getMetaData();
}
public int getRowCount ()
{
result.last();
return result.getRow(); // See http://stackoverflow.com/questions/8292256/get-number-of-rows-returned-by-resultset-in-java
}
public int getColumnCount ()
{
return metadata.getColumnCount();
}
public Object getValueAt (int row, int col)
{
result.absolute(row);
return result.getString(col);
}
public String getColumnName (int col)
{
return metadata.getColumnName(col);
}
public void setValueAt (Object value, int row, int col)
{
result.absolute(row);
result.updateObject(col, value);
}
}
I haven't tested it, but your code must look like this. Note that you mustn't close the Statement, Connection or the ResultSet (or create a new ResultSet cause some db drivers like MySQL destroy the old one) to prevent any Exceptions.
OK!!! i managed to update every cell separately by just editing the cell and then pressing enter!
This works only for 1 table but its ok for my project! Here is the code...
private class RowColumnListSelectionListener implements ListSelectionListener {
public void valueChanged(ListSelectionEvent e) {
rowIndexStart = table.getSelectedRow();
rowIndexEnd = table.getSelectionModel().getMaxSelectionIndex();
colIndexStart = table.getSelectedColumn();
colIndexEnd = table.getColumnModel().getSelectionModel().getMaxSelectionIndex();
for ( i = rowIndexStart; i <= rowIndexEnd; i++) {
for ( j = colIndexStart; j <= colIndexEnd; j++) {
Object cell_value = table.getValueAt(i,j);
Cell_value_string_before = (String) cell_value;
}
}
}
}
public test_table() {
setIconImage(Toolkit.getDefaultToolkit().getImage(test_table.class.getResource("/com/sun/java/swing/plaf/windows/icons/Computer.gif")));
//setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//setBounds(100, 100, 688, 589);
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
xframeWidth = screenSize.width; //dynamic size for frame x-axes
yframeHeight = screenSize.height; //dynamic size for frame y-axes
int xlocation = xframeWidth*2; //dynamic location x-axes
int ylocation = yframeHeight*2; //dynamic location y-axes
setBounds(0,0, xframeWidth, yframeHeight);
setResizable(false);
JMenuBar menuBar = new JMenuBar();
setJMenuBar(menuBar);
JMenu mnNewMenu = new JMenu("Αρχείο");
menuBar.add(mnNewMenu);
JMenuItem mntmNewMenuItem_1 = new JMenuItem("Εξαγωγή σε .txt αρχείο");
mntmNewMenuItem_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JFileChooser fileChooser =new JFileChooser();
fileChooser.setDialogTitle("Δημιουργία αρχείου .txt");
FileNameExtensionFilter filter = new FileNameExtensionFilter(".txt", "text");
fileChooser.setFileFilter(filter);
int returnVal = fileChooser.showSaveDialog(null);
if (returnVal == JFileChooser.APPROVE_OPTION) {
try {
File file = fileChooser.getSelectedFile();
File newfile = new File(file.getPath()+".txt");
// PrintWriter os = new PrintWriter(file);
FileWriter fw = new FileWriter(newfile,true); //filewriter
BufferedWriter bw = new BufferedWriter(fw); //buffered writer
PrintWriter os = new PrintWriter(bw, true);
os.print("");
for (int col = 0; col < table.getColumnCount(); col++) {
os.print(table.getColumnName(col) + "\t");
os.print(";");
}
os.println("");
os.println("");
for (int row = 0; row < table.getRowCount(); row++) {
for (int col = 0; col < table.getColumnCount(); col++) {
//os.print(table.getColumnName(col) + "\t");
// os.print(": ");
os.print(table.getValueAt(row, col) + "\t");
os.print(";");
// os.print(table.getRowCount() + "\t");
}
os.println("");
}
os.close();
System.out.println("Done!");
}
catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
});
mnNewMenu.add(mntmNewMenuItem_1);
JMenuItem mntmNewMenuItem_2 = new JMenuItem("Εκτύπωση");
mntmNewMenuItem_2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
if (! table.print()) {
System.err.println("User cancelled printing");
}
} catch (java.awt.print.PrinterException e1) {
System.err.format("Cannot print %s%n", e1.getMessage());
}
}
});
mnNewMenu.add(mntmNewMenuItem_2);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
ArrayList columnNames = new ArrayList();
ArrayList data = new ArrayList();
// data_connector getdata1 = new data_connector();
// host = getdata1.getHost();
// username = getdata1.getUsername();
// password1 = getdata1.getPassword();
// mysql_command = getdata1.getMysql_command();
// command_name = getdata1.getCommand_name();
//setTitle(command_name);
// Connect to an MySQL Database, run query, get result set
String url = "jdbc:mysql://localhost:3306/υπαλληλοι απε-μπε";
String userid = "ziorange";
String password = "120736";
String sql = "SELECT * FROM `ΥΠΑΛΛΗΛΟΙ 2 test`";
//String sql = "SELECT `ΚΩΔΙΚΟΣ`,`ΕΠΩΝΥΜΟ`,`ΟΝΟΜΑ`,`ΟΝΟΜΑ ΠΑΤΡΟΣ`,`ΑΜΚΑ`,`ΑΡΙΘΜΟΣ ΜΗΤΡΩΟΥ ΙΚΑ (αν υπάρχει)` FROM `ΥΠΑΛΛΗΛΟΙ 2` WHERE `ΚΩΔΙΚΟΣ`>'0' AND `ΗΜΕΡΟΜΗΝΙΑ ΑΠΟΧΩΡΗΣΗΣ`>'2009-12-31 00:00:00' OR `ΕΙΔΙΚΟΤΗΤΑ` !='ΑΝΤΑΠΟΚΡΙΤΗΣ ΕΞ' AND `ΛΟΓΟΣ ΑΠΟΧΩΡΗΣΗΣ`='-' ORDER BY `ΕΠΩΝΥΜΟ`";
// Java SE 7 has try-with-resources
// This will ensure that the sql objects are closed when the program
// is finished with them
try
{
connection = DriverManager.getConnection( url, userid, password );
Statement stmt = connection.createStatement();
ResultSet rs = stmt.executeQuery( sql );
ResultSetMetaData md = rs.getMetaData();
int columns = md.getColumnCount();
// Get column names
for (int i = 1; i <= columns; i++)
{
columnNames.add( md.getColumnName(i) );
}
// Get row data
while (rs.next())
{
ArrayList row = new ArrayList(columns);
for (int i = 1; i <= columns; i++)
{
row.add( rs.getObject(i) );
}
data.add( row );
}
}
catch (SQLException e)
{
//
System.out.println( e.getMessage() );
JOptionPane.showMessageDialog(null, e.getMessage() );
mysql_fail_flag=1;
}
// Create Vectors and copy over elements from ArrayLists to them
// Vector is deprecated but I am using them in this example to keep
// things simple - the best practice would be to create a custom defined
// class which inherits from the AbstractTableModel class
Vector columnNamesVector = new Vector();
Vector dataVector = new Vector();
for (int i = 0; i < data.size(); i++)
{
ArrayList subArray = (ArrayList)data.get(i);
Vector subVector = new Vector();
for (int j = 0; j < subArray.size(); j++)
{
subVector.add(subArray.get(j));
}
dataVector.add(subVector);
}
for (int i = 0; i < columnNames.size(); i++ )
columnNamesVector.add(columnNames.get(i));
contentPane.setLayout(null);
// Create table with database data
table = new JTable(dataVector, columnNamesVector)
{
public Class getColumnClass(int column)
{
for (int row = 0; row < getRowCount(); row++)
{
Object o = getValueAt(row, column);
if (o != null)
{
return o.getClass();
}
}
return Object.class;
}
};
table.setAutoResizeMode(JTable.AUTO_RESIZE_OFF);
table.setColumnSelectionAllowed(true); //epilegei to kathe keli ksexwrista
table.getSelectionModel().addListSelectionListener(
new RowColumnListSelectionListener());
table.getDefaultEditor(String.class).addCellEditorListener(
new CellEditorListener() {
public void editingCanceled(ChangeEvent e) {
System.out.println("editingCanceled");
}
public void editingStopped(ChangeEvent e) {
System.out.println("editingStopped: apply additional action");
rowIndexStart = table.getSelectedRow();
rowIndexEnd = table.getSelectionModel().getMaxSelectionIndex();
colIndexStart = table.getSelectedColumn();
colIndexEnd = table.getColumnModel().getSelectionModel().getMaxSelectionIndex();
for ( i = rowIndexStart; i <= rowIndexEnd; i++) {
for ( j = colIndexStart; j <= colIndexEnd; j++) {
Object cell_value = table.getValueAt(i,j);
Cell_value_string_after = (String) cell_value;
ia=i+1;
ja=j+1;
column_name_selected2 = table.getColumnName(ja-1);
}
}
if(Cell_value_string_before.equals(Cell_value_string_after)){
System.out.println("Do nothing");
}
else{
System.out.println("UPDATE DATABASE");
update_database();
}
}
});
JScrollPane scrollPane = new JScrollPane( table );
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scrollPane.setBounds(5, 5, xframeWidth-20, yframeHeight-70);
getContentPane().add( scrollPane );
JPanel buttonPanel = new JPanel();
buttonPanel.setBounds(5, 856, 1574, 1);
getContentPane().add( buttonPanel );
buttonPanel.setLayout(null);
}
public void update_database(){
Object get_lastname = table.getValueAt(ia-1, 5);
String get_lastname_string = (String) get_lastname;
Object get_name = table.getValueAt(ia-1, 6);
String get_name_string=(String) get_name;
System.out.println("RESULT= "+ column_name_selected2 + " - "+Cell_value_string_after+ " - " + get_lastname_string+ " - " + get_name_string );
if(column_name_selected2.equals("ΕΠΩΝΥΜΟ") || column_name_selected2.equals("ΟΝΟΜΑ")){
JOptionPane.showMessageDialog(null, "To επώνυμο και το όνομα δεν μπορεί να αλλάξει","Μήνυμα:",JOptionPane.WARNING_MESSAGE);
}
else{
try {
PreparedStatement update = (PreparedStatement) connection.prepareStatement
("UPDATE `ΥΠΑΛΛΗΛΟΙ 2 TEST` SET `" +column_name_selected2+"` = ? WHERE ΕΠΩΝΥΜΟ= ? AND ΟΝΟΜΑ =? ");
update.setString(1,Cell_value_string_after);
update.setString(2,get_lastname_string);
update.setString(3,get_name_string);
int all_edit_query_status=update.executeUpdate();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}

jTable in GUI (java) does not show all data from database! error in TableModel?

This is a last resort. I'm studying development of Information Systems and even my teachers can't solve this... this is a nut for you to crack!!
This is the problem: My jTable in GUI gives me this:
This is what Microsoft Management Studio shows me:
As you can tell the jTable (GUI) has got 2 main problems:
The columnname "Name" does not contain any information. And it should? Why isn't it showing?
Since as you can tell, the table contains several columns, too many to even show. I therefore want to "add a restriction" that changes so that the jTable only shows the first 6 columns.
This is the code for the "creation of the table", in the DataAccessLayer:
private TableModel getResultSetAsDefaultTableModel(ResultSet rs) {
try {
String[] columnHeadings = new String[0];
Object[][] dataArray = new Object[0][0];
ResultSetMetaData md = rs.getMetaData();
int columnCount = md.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
String columnName = md.getColumnName(i);
columnHeadings = Arrays.copyOf(columnHeadings, columnHeadings.length + 1);
columnHeadings[i - 1] = columnName;
}
int r = 0;
while (rs.next()) {
Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; i++) {
row[i - 1] = rs.getObject(i);
}
dataArray = Arrays.copyOf(dataArray, dataArray.length + 1);
dataArray[r] = row;
r++;
}
DefaultTableModel dtm = new DefaultTableModel(dataArray, columnHeadings) {
public boolean isCellEditable(int row, int column) {
return false;
}
};
return dtm;
} catch (SQLException ex) {
Logger.getLogger(Dataaccesslayer.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
If you want me to show you the path of the code (frame, controller) just say so and I'll post it.
I would be so thankful if anyone can solve this...
Regards,
Christian
I think it is because in your for loop it should say i = 0; and not i = 1; since the first information (the name) is at index 0 right ?
In your case it could be enough to just leave the for-loop as it is and change this line to:row[i - 1] = rs.getObject(i-1);
To hide or show columns you could call setMin setMax and setPreferredWidth on your TableColumn.
Change your method like next, I think it helps you:
private TableModel getResultSetAsDefaultTableModel(ResultSet rs) {
try {
List<String> columnHeadings = new ArrayList<String>();
Object[][] dataArray = new Object[0][0];
ResultSetMetaData md = rs.getMetaData();
int columnCount = md.getColumnCount();
for (int i = 1; i <= columnCount; i++) {
columnHeadings.add(md.getColumnName(i));
}
int r = 0;
while (rs.next()) {
Object[] row = new Object[columnCount];
for (int i = 1; i <= columnCount; i++) {
row[i-1] = rs.getObject(i);
}
dataArray = Arrays.copyOf(dataArray, dataArray.length + 1);
dataArray[r] = row;
r++;
}
DefaultTableModel dtm = new DefaultTableModel(dataArray,columnHeadings.toArray(new Object[columnHeadings.size()])) {
public boolean isCellEditable(int row, int column) {
return false;
}
};
return dtm;
} catch (SQLException ex) {
Logger.getLogger(Dataaccesslayer.class.getName()).log(Level.SEVERE,null, ex);
}
return null;
}
For showing not all columns use dtm.setColumnCount(2);. Here 2 is column count to show.

ResultSet.beforeFirst() gets ignored in Java

I would like to create DefaultTableModel from ResultSet. To do that, I need Object[][].
For that, I have to specify the size of the object before I iterate through the table: I go to the rs.last(), then rs.getRow(), then rs.beforeFirst();
After that, the rs.next() does not executes in the while cycle.
What am I doing wrong?
public static DefaultTableModel buildTableModel(ResultSet _resultSet) {
ResultSetMetaData metaData;
Object[] columnNames = null;
Object[][] tableData = null;
int columnCount;
int currentRowNumber = 0;
try {
metaData = _resultSet.getMetaData();
columnCount = metaData.getColumnCount();
columnNames = new Object[columnCount];
_resultSet.last();
tableData = new Object[_resultSet.getRow()][columnCount];
_resultSet.beforeFirst();
for (int currentColumn = 0; currentColumn <= columnCount; currentColumn++) {
columnNames[currentColumn] = metaData.getColumnName(currentColumn + 1);
}
while (_resultSet.next()) {
for (int columnIndex = 0; columnIndex <= columnCount; columnIndex++) {
tableData[currentRowNumber][columnIndex] = _resultSet.getObject(columnIndex + 1);
}
currentRowNumber++;
}
} catch (SQLException ex) {
System.out.println("bad");
}
return new DefaultTableModel(tableData, columnNames);
}
Probably your ResultSet is not scroll insensitive, that is, it can only be traversed forward.
See the documentation here:
[...] A default ResultSet object is not updatable and has a cursor that moves forward only. Thus, you can iterate through it only once and only from the first row to the last row. [...]
To create a bi-directional one, do something like:
Connection conn = DriverManager.getConnection(...);
Statement stmt = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ...);
ResultSet rset = stmt.executeQuery(sql);
At first you need to print column name from ResultSetMetaData. Than you apply _resultSet.last(); and _resultSet.beforeFirst();. This way it has been working my machine.
public static DefaultTableModel buildTableModel(ResultSet _resultSet) {
ResultSetMetaData metaData;
Object[] columnNames = null;
Object[][] tableData = null;
int columnCount;
int currentRowNumber = 0;
try {
metaData = _resultSet.getMetaData();
columnCount = metaData.getColumnCount();
columnNames = new Object[columnCount];
// Print column here.
for (int currentColumn = 0; currentColumn <= columnCount; currentColumn++) {
columnNames[currentColumn] = metaData.getColumnName(currentColumn + 1);
}
tableData = new Object[_resultSet.getRow()][columnCount];
//Here point resultSet cursor to last and beforeFirst.
_resultSet.last();
_resultSet.beforeFirst();
// After swaping the above part. Now it will enter on while loop.
while (_resultSet.next()) {
for (int columnIndex = 0; columnIndex <= columnCount; columnIndex++) {
tableData[currentRowNumber][columnIndex] = _resultSet.getObject(columnIndex + 1);
}
currentRowNumber++;
}
} catch (SQLException ex) {
System.out.println("bad");
}
return new DefaultTableModel(tableData, columnNames);
}

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