errorhandling.java

vc ADO 连接数据库

//******************************************************************************
// ErrorHandling.java:	Applet
//
//******************************************************************************
import java.applet.*;
import java.awt.*;
import com.ms.com.*;
import msado15.*;

//==============================================================================
// Main Class for applet ErrorHandling
//
//==============================================================================
public class ErrorHandling extends Applet implements Runnable
{
	// THREAD SUPPORT:
	//		m_ErrorHandling	is the Thread object for the applet
	//--------------------------------------------------------------------------
	private Thread	 m_ErrorHandling = null;

	// ANIMATION SUPPORT:
	//		m_Graphics		used for storing the applet's Graphics context
	//		m_Images[]		the array of Image objects for the animation
	//		m_nCurrImage	the index of the next image to be displayed
	//		m_ImgWidth		width of each image
	//		m_ImgHeight		height of each image
	//		m_fAllLoaded	indicates whether all images have been loaded
	//		NUM_IMAGES 		number of images used in the animation
	//--------------------------------------------------------------------------
	private Graphics m_Graphics;
	private Image	 m_Images[];
	private int 	 m_nCurrImage;
	private int 	 m_nImgWidth  = 0;
	private int 	 m_nImgHeight = 0;
	private boolean  m_fAllLoaded = false;
	private final int NUM_IMAGES = 18;


	// ErrorHandling Class Constructor
	//--------------------------------------------------------------------------
	public ErrorHandling()
	{
		// TODO: Add constructor code here
	}

	// APPLET INFO SUPPORT:
	//		The getAppletInfo() method returns a string describing the applet's
	// author, copyright date, or miscellaneous information.
    //--------------------------------------------------------------------------
	public String getAppletInfo()
	{
		return "Name: ErrorHandling\r\n" +
		       "Author: Don Willits\r\n" +
		       "Created with Microsoft Visual J++ Version 1.1";
	}


	// The init() method is called by the AWT when an applet is first loaded or
	// reloaded.  Override this method to perform whatever initialization your
	// applet needs, such as initializing data structures, loading images or
	// fonts, creating frame windows, setting the layout manager, or adding UI
	// components.
    //--------------------------------------------------------------------------
	public void init()
	{
        // If you use a ResourceWizard-generated "control creator" class to
        // arrange controls in your applet, you may want to call its
        // CreateControls() method from within this method. Remove the following
        // call to resize() before adding the call to CreateControls();
        // CreateControls() does its own resizing.
        //----------------------------------------------------------------------
    	resize(320, 240);

		// TODO: Place additional initialization code here
	}

	// Place additional applet clean up code here.  destroy() is called when
	// when you applet is terminating and being unloaded.
	//-------------------------------------------------------------------------
	public void destroy()
	{
		// TODO: Place applet cleanup code here
	}

    // ANIMATION SUPPORT:
    //		Draws the next image, if all images are currently loaded
    //--------------------------------------------------------------------------
	private void displayImage(Graphics g)
	{
		if (!m_fAllLoaded)
			return;

		// Draw Image in center of applet
		//----------------------------------------------------------------------
		g.drawImage(m_Images[m_nCurrImage],
				   (size().width - m_nImgWidth)   / 2,
				   (size().height - m_nImgHeight) / 2, null);
	}

	// ErrorHandling Paint Handler
	//--------------------------------------------------------------------------
	public void paint(Graphics g)
	{
		// ANIMATION SUPPORT:
		//		The following code displays a status message until all the
		// images are loaded. Then it calls displayImage to display the current
		// image.
		//----------------------------------------------------------------------
		if (m_fAllLoaded)
		{
			Rectangle r = g.getClipRect();
			
			g.clearRect(r.x, r.y, r.width, r.height);
			displayImage(g);
		}
		else
			g.drawString("Loading images...", 10, 20);

		// TODO: Place additional applet Paint code here
	}

	//		The start() method is called when the page containing the applet
	// first appears on the screen. The AppletWizard's initial implementation
	// of this method starts execution of the applet's thread.
	//--------------------------------------------------------------------------
	public void start()
	{
		if (m_ErrorHandling == null)
		{
			m_ErrorHandling = new Thread(this);
			m_ErrorHandling.start();
		}
		// TODO: Place additional applet start code here
	}
	
	//		The stop() method is called when the page containing the applet is
	// no longer on the screen. The AppletWizard's initial implementation of
	// this method stops execution of the applet's thread.
	//--------------------------------------------------------------------------
	public void stop()
	{
		if (m_ErrorHandling != null)
		{
			m_ErrorHandling.stop();
			m_ErrorHandling = null;
		}

		// TODO: Place additional applet stop code here
	}

	// THREAD SUPPORT
	//		The run() method is called when the applet's thread is started. If
	// your applet performs any ongoing activities without waiting for user
	// input, the code for implementing that behavior typically goes here. For
	// example, for an applet that performs animation, the run() method controls
	// the display of images.
	//--------------------------------------------------------------------------
	public void run()
	{
		m_nCurrImage = 0;
		
		// If re-entering the page, then the images have already been loaded.
		// m_fAllLoaded == TRUE.
		//----------------------------------------------------------------------
        if (!m_fAllLoaded)
		{
    		repaint();
    		m_Graphics = getGraphics();
    		m_Images   = new Image[NUM_IMAGES];

    		// Load in all the images
    		//------------------------------------------------------------------
    		MediaTracker tracker = new MediaTracker(this);
    		String strImage;

    		// For each image in the animation, this method first constructs a
    		// string containing the path to the image file; then it begins
    		// loading the image into the m_Images array.  Note that the call to
    		// getImage will return before the image is completely loaded.
    		//------------------------------------------------------------------
    		for (int i = 1; i <= NUM_IMAGES; i++)
    		{
    			// Build path to next image
    			//--------------------------------------------------------------
    			strImage = "images/img00" + ((i < 10) ? "0" : "") + i + ".gif";
			    m_Images[i-1] = getImage(getDocumentBase(), strImage);

                tracker.addImage(m_Images[i-1], 0);
    		}

    		// Wait until all images are fully loaded
    		//------------------------------------------------------------------
			try
			{
				tracker.waitForAll();
				m_fAllLoaded = !tracker.isErrorAny();
			}
			catch (InterruptedException e)
			{
				// TODO: Place exception-handling code here in case an
				//       InterruptedException is thrown by Thread.sleep(),
				//		 meaning that another thread has interrupted this one
			}
			
			if (!m_fAllLoaded)
			{
			    stop();
			    m_Graphics.drawString("Error loading images!", 10, 40);
			    return;
			}
			

			// Assuming all images are same width and height.
			//--------------------------------------------------------------
		    m_nImgWidth  = m_Images[0].getWidth(this);
		    m_nImgHeight = m_Images[0].getHeight(this);
        }		
		repaint();

		while (true)
		{
			try
			{
				// Draw next image in animation
				//--------------------------------------------------------------
				displayImage(m_Graphics);
				m_nCurrImage++;
				if (m_nCurrImage == NUM_IMAGES)
					m_nCurrImage = 0;

				// TODO:  Add additional thread-specific code here
				Thread.sleep(50);
			}
			catch (InterruptedException e)
			{
				// TODO: Place exception-handling code here in case an
				//       InterruptedException is thrown by Thread.sleep(),
				//		 meaning that another thread has interrupted this one
				stop();
			}
		}
	}

public static void AdoErrorEx( msado15._Connection Conn1 )
{
    // Local Error Objects
    msado15.Errors      Errs1 = null;
    msado15.Error       Err1  = null;

    long        nCount;
    Variant     v = new Variant();

    if ( Conn1 == null )
        return;

    Errs1  = Conn1.getErrors();
    nCount = Errs1.getCount();
    for( long i = 0; i < nCount; i++ )
    {
        v.putInt( (int) i );
        Err1 = Errs1.getItem( v );
        System.out.println( "    Number " + Err1.getNumber() );
        System.out.println( "        Description = " + Err1.getDescription()  );
        if ( Err1 != null ) Err1 = null;
    }
    if ( Errs1 != null ) Errs1 = null;
}

public static void main( String args[])
{
    msado15._Connection Conn1      = new msado15.Connection();

    try
    {
        Conn1.Open( "", "", "", -1  );
    }
    // Catch Blocks -- These catch blocks are a subset of the 
    //                 Exception Handling demonstrated in LogEx.Java &
    //                 AdoUtils.java in the Java Rosetta Stone Samples    
    catch (com.ms.com.ComFailException e)    
    {
        // Test if Connection.Errors Collection is non-empty 
        AdoErrorEx( Conn1 );

        // Crack open ComFailure class that wraps COM Exceptions
        System.out.println( "ComFailException Class Raised:" );
        System.out.println( "Exception Class = " + e.getClass()   );
        System.out.println( "Error Message   = " + e.getMessage() );
        System.out.println( "Failed HRESULT  = " + e.getHResult() ); 
    }
    catch(Exception e) 
    {
        // Test if Connection.Errors Collection is non-empty
        AdoErrorEx( Conn1 );

        // Crack open Java Exception class
        System.out.println( "Exception Class Raised:" );
        System.out.println( "Exception Class = " + e.getClass()   );
        System.out.println( "Error Message   = " + e.getMessage() );
    }
}
}