В настоящее время я работаю над примером приложения в Java. Я на самом деле не использовал java для чего-то большего, чем просто привет, поэтому, пожалуйста, потерпите меня Я настроил свое приложение так, чтобы оно запрашивало базу данных mysql. Проблема, с которой я столкнулся, связана с обновлением содержимого во фрейме. В настоящее время я открываю новое окно с контентом при каждом запросе. Это связано с моим ограниченным знанием Java. Я хотел бы обновить содержимое в рамке, не создавая новое окно.
вот код:
// Import the swing and AWT classes needed
import java.awt.EventQueue;
import java.awt.FlowLayout;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.BoxLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.*;
import java.awt.Component;
import java.awt.Container;
import java.util.*;
import java.awt.event.*;
import java.util.Timer;
import java.util.TimerTask;
/**
* Basic Swing example.
*/
public class client extends JPanel {
public static void main(String[] args) {
// Make sure all Swing/AWT instantiations and accesses are done on the
// Create a JFrame, which is a Window with "decorations", i.e.
// title, border and close-button
JFrame f = new JFrame("Densebrain Test Client");
// Set a simple Layout Manager that arranges the contained
// Components
f.setLayout(new FlowLayout());
// Add some Components
f.add(new JLabel("Hello, world!"));
f.add(new JButton("Press me!"));
// "Pack" the window, making it "just big enough".
f.pack();
// Set the default close operation for the window, or else the
// program won't exit when clicking close button
// (The default is HIDE_ON_CLOSE, which just makes the window
// invisible, and thus doesn't exit the app)
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
// Set the visibility as true, thereby displaying it
f.setVisible(true);
int delay = 0; // delay for 5 sec.
int period = 5000; // repeat every sec.
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
public void run() {
runn();
}
}, delay, period);
//runn();
}
public static void runn() {
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver").newInstance();
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/densebrain",
"root", "");
if(!con.isClosed())
{
System.out.println("Successfully connected to " +
"MySQL server using TCP/IP...");
stmt = con.createStatement();
try {
rs = stmt.executeQuery( "SELECT * FROM posts" );
try {
JFrame f = new JFrame("POSTS");
f.setLayout(new GridLayout(40,1));
//pane = f.getContentPane();
//getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.Y_AXIS));
while ( rs.next() ) {
int numColumns = rs.getMetaData().getColumnCount();
for ( int i = 1 ; i <= numColumns ; i++ ) {
// Column numbers start at 1.
// Also there are many methods on the result set to return
// the column as a particular type. Refer to the Sun documentation
// for the list of valid conversions.
System.out.println( "COLUMN " + i + " = " + rs.getObject(i) );
switch(i)
{
case 1:
break;
case 2: f.add(new JLabel("NAME = " + rs.getObject(i)));
break;
case 3: f.add(new JLabel("CONTENT = " + rs.getObject(i)));
break;
case 4: f.add(new JLabel("CREATED = " + rs.getObject(i)));
break;
}
}
f.add(new JLabel("*********"));
}
f.pack();
// Set the default close operation for the window, or else the
// program won't exit when clicking close button
// (The default is HIDE_ON_CLOSE, which just makes the window
// invisible, and thus doesn't exit the app)
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
// Set the visibility as true, thereby displaying it
f.setVisible(true);
} finally {
try { rs.close(); } catch (SQLException ignore) { /* Propagate the original exception instead of this one that you may want just logged */ }
}
} finally {
try { stmt.close(); } catch (SQLException ignore) { /* Propagate the original exception instead of this one that you may want just logged */ }
}
}
} catch(Exception e) {
System.err.println("Exception: " + e.getMessage());
} finally {
try {
if(con != null)
con.close();
} catch(SQLException e) {}
}
}
}