Исходный текст программы CheckCheckSum.java

Назад

// ==========================================
// CheckCheckSum.java
//(C) Alexandr Frolov, 1998
// E-mail: frolov@glasnet.ru
// Web:    http://www.glasnet.ru/~frolov 
// ==========================================

import java.applet.*;
import java.awt.*;
import java.net.*;
import java.io.*;
import java.util.zip.*;

public class CheckCheckSum extends Applet 
{
  URL u;
  String szChecksum = null;
  Checksum cs = new CRC32();

  // ============================================
  // init
  // ============================================
  public void init()
  {
    try
    {
      u = getCodeBase();
      u = new URL(u.toString() + 
	"CheckCheckSum.class");
      
      InputStream is = u.openStream();
      
      CheckedInputStream cis = 
	new CheckedInputStream(is, cs);
      
      szChecksum = calculate(cis);
    }
    catch(Exception ioe)
    {
      showStatus(ioe.toString());
    }
    
    setBackground(Color.yellow);
  }
  
  // ============================================
  // calculate
  // ============================================
  String calculate(CheckedInputStream is)
  {
    byte[] buf = new byte[8000];
    int nLength = 0;
    try
    {
      while(true)
      {
        int nReaded = is.read(buf);
        if(nReaded == -1)
          break;
      }
      is.close();
    }
    catch(Exception ioe)
    {
      showStatus(ioe.toString());
    }

    String s = (new Long(
      is.getChecksum().getValue())).toString();
    return s;
  }
  
  // ============================================
  // paint
  // ============================================
  public void paint(Graphics g)
  {
    g.drawString("My own URL: " + u.toString(),
       10, 30);
    g.drawString("My own CRC-32: " + szChecksum,
       10, 50);
  }
}

Назад