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Allgemein: Vorlesungen Labore Sinnvolle Programme Lineare Regression GUI-Entwurfsarbeit Single-Format Design Pattern-Termine Observer1 Bsp2 Json-Array Json-Dialogelemente Webtechnologien

Bsp2

	// Einfaches Beispiel mit Ausgabe in einem Editor
	// Schalter und ComboBox vereinfachen die Aktionen

	import javax.swing.*;

	import java.awt.*;
	import java.awt.event.*;
	
	import java.sql.*;

	

	public class Bsp2 extends JFrame {

	    JToolBar toolbar = new JToolBar();
	    JTextArea editor  = new JTextArea("");
	    JButton BnSQL;
	    JButton BnESC;

	    JLabel lFormel;
	    JComboBox TSql;
	    

	        /** Creates a new instance of Main */
	    public Bsp2() {
	        setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
	        setSize(900,400);        
	        setGUI();
	    }
	    
	    private void setGUI() {
	      this.getContentPane().setLayout( new BorderLayout() );

	      JScrollPane sc = new JScrollPane(editor);
	      this.getContentPane().add(sc, BorderLayout.CENTER);

	      editor.setFont( new Font("Courier New", Font.BOLD,18)  );

	      JPanel panel1 = new JPanel();
	      panel1.setLayout(  new GridBagLayout() );
	      
	      BnSQL = new JButton("Starte SQL");
	      BnESC = new JButton("Ende");
	      BnSQL.setFont( new Font("Arial", Font.BOLD,18)  );


	      BnSQL.addActionListener(new java.awt.event.ActionListener() {
	        public void actionPerformed(ActionEvent e) {
	          BnSQL_Click();
	        }
	      });
	      BnESC.addActionListener(new java.awt.event.ActionListener() {
	        public void actionPerformed(ActionEvent e) {
	          BnESC_Click();
	        }
	      });
	        
	      
	      
	      lFormel = new JLabel("SQL-Befehl");
	      lFormel.setFont( new Font("Arial", Font.BOLD,18) );
	      panel1.add(lFormel, new GridBagConstraints(0, 0, 1, 1, 0.0, 0.0
	              ,GridBagConstraints.WEST, GridBagConstraints.NONE, new Insets(20,20,0,0), 0, 6));

	      String sTable="employee";
	        // ComboBox mit Eingabe
	      String[] items = new String[4];
	      items[0] = "SELECT EMP_NO, Full_name, DEPT_NO, SALARY FROM " + sTable;
	      items[1] = "SELECT *  FROM " + sTable;
	      items[2] = "SELECT *  FROM " + sTable+"  WHERE SALARY > 70000.0";
	      items[3] = "SELECT EMP_NO, Last_name, First_name, DEPT_NO, SALARY FROM " + sTable+"  WHERE SALARY > 70000.0";
	    
	      TSql = new JComboBox(items);
	      TSql.setFont( new Font("Arial", Font.PLAIN,18) );
	      panel1.add(TSql,   new GridBagConstraints(1, 0, 1, 1, 1.0, 0.0
	              ,GridBagConstraints.WEST, GridBagConstraints.HORIZONTAL, new Insets(20,40,0,20), 00, 0));
	      TSql.setEditable(true);
	      
	      panel1.add(BnSQL, new GridBagConstraints(2, 0, 1, 1, 0.0, 0.0
	              ,GridBagConstraints.WEST, GridBagConstraints.NONE, new Insets(20,20,0,0), 0, 6));
	      
	      this.getContentPane().add(panel1, BorderLayout.NORTH);
	      
	    }  // setGUI

	    private void BnESC_Click() {
	         System.exit(0);        
	    }


	    public void BnSQL_Click()  {   // throws Exception  {
	      String sDbDrv;
	      String sDbUrl;

	      String sTable="employee";
	      String sUsr="sysdba";
	      String sPwd="masterkey";

	      sDbDrv = "org.firebirdsql.jdbc.FBDriver";
	      sDbUrl="jdbc:firebirdsql:localhost/3050:d:\\progs\\eclipse\\JDBC1_2018\\EMPLOYEE.FDB";


	        // Verbindung zur Datenbank, Auslese Variablen
	      Connection cn = null;
	      Statement  st = null;
	      ResultSet  rs = null;
	      
	      editor.setText("");
	      try {
	        
	        // Treiber INIT, Verbinden  und SQL-Statement auslösen
	        // Returns the Class object associated with the class or interface with the given string name.
	        // class c = Class.forName( sDbDrv );
	        Class.forName( sDbDrv );
	        
	        cn = DriverManager.getConnection( sDbUrl, sUsr, sPwd );
	        st = cn.createStatement();
	        
	        String sql = (String) TSql.getSelectedItem();
	        rs = st.executeQuery( sql );

	        // Get meta data:
	        ResultSetMetaData rsmd = rs.getMetaData();
	        int i, AnzCols;
	        AnzCols = rsmd.getColumnCount();
	        // Ausgabe der Tabelle:
	        // Oberste Zeile
	        String s="";
	        for( i=0; i iWantLen )
	        return s.substring( 0, iWantLen );
	    else
	        return s;
	  }

	    public static void main(String[] args) {
	    	Bsp2 frame = new Bsp2();
	       frame.setVisible(true);
	    }
	    
	}

Gehe zu: Observer1 Json-Array