计数器的例子..txt

这里有个JAVA和CGI程序结合的访问计数器的例子. 其实单纯做访问计数器

这里有个JAVA和CGI程序结合的访问计数器的例子. 
其实单纯做访问计数器，只有CGI就够了. 
但希望统计用户访问该主页的时间时,只用CGI好象就不行了. (本例没有这个功能. :PPP) 
 
count.pl 
-------------------------------------------------------------- 
#!/usr/local/bin/perl 
# Increments a visit count stored in the file named 
# "counter" and send the count as a plain text document. 
 
# Print a minimal MIME header 
    print "Content-type: text/plain\n\n"; 
 
    $counterfile = "counter"; 
 
# Open the counter file and get current count 
    open(COUNTER, "$counterfile"); 
 
# Lock the file to guard against another process updating the 
# file as this script uses it 
    $lock_exclusive = 2; 
    $unlock = 8; 
    flock(COUNTER, $lock_exclusive); 
 
# Read and increment the count 
    $line = <COUNTER>; 
    close(COUNTER); 
 
    chop($line); 
    $count = $line; 
    $count++; 
 
# Save the new count in the file 
    open(COUNTER, ">$counterfile"); 
    print COUNTER ("$count\n"); 
    close(COUNTER);     
         
# Remember to unlock the file 
    flock(COUNTER, $unlock); 
 
# Send count to caller 
    print "$count\n";    
------------------------------------------------------------ 
VisitCount.java 
 
---------------------------------------------------------- 
//--------------------------------------------------------------- 
// File: VisitCount.java 
// Accesses a CGI program to update visit count and display 
// the current count. 
// Compile with: javac VisitCount.java 
/* 
 * The VisitCount class is a Java applet that accesses a CGI  
 * program at the host URL and retrieves the visitor count (the  
 * CGI program also updates the count). Then it displays the  
 * current count. Use an <applet> tag to embed this applet 
 * at the location where you want to display the count. 
*/ 
//--------------------------------------------------------------- 
import java.awt.*; 
import java.applet.*; 
import java.net.*; 
import java.io.*; 
public class VisitCount extends java.applet.Applet 
{ 
    String visitCount;  // String to store visitor count  
// Class initialization method 
    public void init() 
    { 
        try 
        { 
// Open the URL that counts visitors to this site 
// *** Edit URL before using at your site *** 
            URL url = new URL( 
              "http://www.lnbsoft.com/exec-bin/count.pl?update=1"); 
 
// Open a data stream and read a single line  
            try 
            { 
                DataInputStream in = new  
                    DataInputStream(url.openStream()); 
                visitCount = in.readLine(); 
            } 
            catch(IOException e) {} 
        } 
        catch(MalformedURLException e) {} 
    } 
// Method that paints the output 
    public void paint(java.awt.Graphics gc) 
    { 
// Display the visitor count that was read from the URL 
// Use whatever font style and color you want 
// I used Helvetica for a message and a Courier font 
// for the visitor count 
 
        Font helv = new Font("Helvetica", Font.BOLD, 16); 
        Font courier = new Font("Courier", Font.BOLD, 24); 
 
        gc.setFont(helv); 
        FontMetrics fm = gc.getFontMetrics(); 
        String message = "Visitor number: "; 
        int xstart = 0; 
        int ystart = fm.getHeight(); 
        gc.drawString(message, xstart, ystart); 
 
// Advance horizontally by amount needed to display message 
        xstart += fm.stringWidth(message); 
 
// Change font to Courier and display the count 
        gc.setFont(courier); 
        gc.setColor(Color.red); 
        gc.drawString(visitCount, xstart, ystart); 
    } 
}        
----------------------------------------------------------------- 
 
HTML文件中调用方法. 
<applet code=VisitCount width=200 height=26 align=middle></applet>