displayqueryresults.java~2~

许多开发者和用户都在寻找Java程序中访问数据库的便捷方法。由于Java是一个健壮

 import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

public class DisplayQueryResults extends JFrame {
  // JDBC driver name and database URL
  static final String JDBC_DRIVER =
    "com.microsoft.jdbc.sqlserver.SQLServerDriver";
  static final String DATABASE_URL =
    "jdbc:microsoft:sqlserver://BILLGATES:1433;" +
    "user=fengwei;password=fengwei;databasename=books";
  // default query retrieves all data from authors table
  static final String DEFAULT_QUERY = "SELECT * FROM authors";

  private ResultSetTableModel tableModel;
  private JTextArea queryArea;

  public DisplayQueryResults() {
    super("Displaying Query Results");
    try {
      tableModel = new ResultSetTableModel(JDBC_DRIVER, DATABASE_URL,
					   DEFAULT_QUERY);

      queryArea = new JTextArea(DEFAULT_QUERY, 3, 100);
      queryArea.setWrapStyleWord(true);
      queryArea.setLineWrap(ture);

      JScrollPane scrollPane = new JScrollPane(queryArea,
					       ScrollPaneConstants.
					       VERTICAL_SCROLLBAR_AS_NEEDED,
					       ScrollPaneConstants.
					       HORIZONTAL_SCROLLBAR_NEVER);

      JButton submitButton = new JButton("Submit Query");

      Box box = Box.createHorizontalBox();
      box.add(scrollPane);
      box.add(submitButton);

      JTable resultTable = new JTable(tableModel);

      Container c = getContentPane();
      c.add(box, BorderLayout.NORTH);
      c.add(new JScrollPane(resultTable), BorderLayout.CENTER);

      submitButton.addActionListener(
	  new ActionListener() {
	public void actionPerformed(ActionEvent event) {
	  try {
	    tableModel.setQuery(queryArea.getText());
	  }
	  catch (SQLException sqlException) {
	    JOptionPane.showMessageDialog(null, sqlException.getMessage(),
					  "Database Error",
					  JOptionPane.ERROR_MESSAGE);

	    try {
	      tableModel.setQuery(DEFAULT_QUERY);
	      queryArea.setText(DEFAULT_QUERY);
	    }
	    catch (SQLException sqlException2) {
	      JOptionPane.showMessageDialog(null,
					    sqlException2.getMessage(),
					    "Database Error",
					    JOptionPane.ERROR_MESSAGE);
	      // ensure database connection is closed
	      tableModel.disconnectFromDatabase();
	      System.exit(1);
	    } // end inner catch
	  } // end outter catch
	} // end actionPerformed
      } // end anonymous class ActionListener
    ); // end call to addActionListener

      // set window size and display window
      setSize(500, 250);
      setVisible(true);
    } // end try

    // detect problems loading database driver
    catch( ClassNotFoundException classNotFound ) {
      JOptionPane.showMessageDialog( null, classNotFound.getMessage(),
	"Driver Not Found", JOptionPane.ERROR_MESSAGE );
      System.exit( 1 );
    }

    // catch SQLException thrown by ResultSetTableModel
    // if problems occur while setting up database
    // connection and querying database
    catch( SQLException sqlException ) {
      JOptionPane.showMessageDialog( null, sqlException.getMessage(),
	"Database Error", JOptionPane.ERROR_MESSAGE );

      tableModel.disconnectFromDatabase();
      System.exit( 1 );
    }

    setDefaultCloseOperation( DISPOSE_ON_CLOSE );

    addWindowListener(
	new WindowAdapter() {
	  public void windowClosed( WindowEvent event ) {
	    tableModel.disconnectFromDatabase();
	    System.exit( 0 );
	  }
	}
    );
  } // end DisplayQueryResults constructor

  public static void main( String args[] ) {
    new DisplayQueryResults();
  }

} // end class DisplayQueryResults