数字时钟（代码）

import java.applet.*; import java.awt.*; import java.awt.image.*; import java.util.Hashtable; import java.util.*; /* Example of calling convention: The default 24 hr format: To display time in 12 hr format: To display NewYork time: 12 or 24 hr format (24 hr format - default) (12 hr format) the format for value is GMT+-hhmm, for example (6 hours west of Greenwich meridian) (4 hours, 30 minutes west of Greenwich meridian) (Greenwich) (5 hours east of Greenwich meridian) (show date with time) (don't show date - default) (do not wrap clock with frame) (do not show version info when the mouse cursor is moved on the applet) (change foreground color, color can be any of red,green,blue,cyan,magenta, yellow,orange,pink,black,white or a 6 digit hex number like ff0000) (change background color) */ public class Dgclock extends Applet implements Runnable { MediaTracker tracker; Thread timer=null; boolean suspended=false; Image big_image, buf_image; int bdigit_width=15; int bdigit_height=20; int sdigit_width=7; int sdigit_height=9; int base_width=100; int base_height=30; int offset=4; String TimeFormat="%H"; long TimeDiff=0L; boolean ShowDate=false; boolean ShowStatus=true; boolean use_frame=true; Color bg_color=Color.black; /** * Cache of colors indexed by name or color-spec. */ static Hashtable colorCache = new Hashtable(); /** * Initialize the color hash table. */ static { colorCache.put("red", Color.red); colorCache.put("green", Color.green); colorCache.put("blue", Color.blue); colorCache.put("cyan", Color.cyan); colorCache.put("magenta", Color.magenta); colorCache.put("yellow", Color.yellow); colorCache.put("orange", Color.orange); colorCache.put("pink", Color.pink); colorCache.put("white", Color.white); colorCache.put("black", Color.black); } int checkTZ(String TZ) { int d; int hr, min; int counter=0; int diff=0; hr=0; min=0; if (TZ != null) { int length=TZ.length(); if (length == 8) { //Print("Length= " + length); int c=TZ.charAt(3); if ((c == '-') || (c == '+')) { String tzval=TZ.substring(4,8); //Print("TZ value= " + tzval); for (int i=0; i < tzval.length(); i++) { d=tzval.charAt(i); if ( (d >= '0') && d <= '9') { if (counter < 2) hr=hr*10+(d-'0'); else min=min*10+(d-'0'); counter++; } } //Print("Hour: " + hr + " Min: " + min); diff=(hr*60)+min; if (c == '-') diff=(-diff); } } } return diff; } public void init() { int x, y; Image rgb_image=null; String fg, bg; fg=bg=null; // check if TimeFormat is supplied TimeFormat=getParameter("TimeFormat"); if (TimeFormat != null) { if ((!TimeFormat.equals("%I")) && (!TimeFormat.equals("%H"))) TimeFormat="%H"; } else TimeFormat="%H"; String gp=getParameter("ShowDate"); if (gp != null) { if (gp.equals("yes")) ShowDate=true; } gp=getParameter("ShowVersion"); if (gp != null) { if (gp.equals("no")) ShowStatus=false; } // check if frame need to be displayed gp=getParameter("ShowFrame"); if (gp != null) { if (gp.equals("no")) { use_frame=false; /* offset=0; base_width=89; base_height=20; */ } } // check if fg and bg parameters are supplied fg=getParameter("fg"); bg=getParameter("bg"); //Print("TImeForamt= " + TimeFormat); tracker=new MediaTracker(this); try { // load the big image if ((fg == null) && (bg == null)) { //Print("fg and bg null"); big_image=getImage(getCodeBase(),"./dgstrip.gif"); tracker.addImage(big_image,0); } else { rgb_image=getImage(getCodeBase(),"./dgstrip.gif"); tracker.addImage(rgb_image,0); } } catch (Exception e) {;} if ((fg != null) || (bg != null)) { //Print ("fg or bg is not null"); Color fgc, bgc; if (fg != null) fgc=lookupColor(true,fg); else fgc=Color.cyan; if (bg != null) bgc=lookupColor(false,bg); else bgc=Color.black; bg_color=bgc; ImageFilter f=new ColorFilter(fgc,bgc); ImageProducer producer=new FilteredImageSource( rgb_image.getSource(),f); big_image=this.createImage(producer); } // check for TZ int diff=0; String timezone=getParameter("TZ"); if (timezone != null) { if (timezone.equals("LOCAL")) TimeDiff=0L; else { Date date=new Date(); diff=checkTZ(timezone); TimeDiff=((long) date.getTimezoneOffset())*60000+diff*60000; } } try { buf_image=createImage(base_width,base_height); } catch (Exception e) {;} //jdk 1.1 on osf found a problem } /** * taken from AlphaBullet applet by Jim Graham */ private synchronized Color lookupColor(boolean bb,String colorname) { /** * boolean bb is true when looking color for foreground * we need this flag, so if color lookup fails, we can choose * contrasting colors for fg and bg */ String lowername=colorname.toLowerCase(); Color newcolor=(Color) colorCache.get(lowername); if (newcolor != null) return newcolor; int colorval; try { colorval=Integer.parseInt(lowername,16); } catch (NumberFormatException e) { if (bb == true) return (Color.cyan); else return (Color.black); } int r=(colorval >> 16) & 0xff; int g=(colorval >> 8) & 0xff; int b=(colorval & 0xff); newcolor=new Color(r,g,b); colorCache.put(lowername,newcolor); return (newcolor); } public void start() { if (timer == null) { timer=new Thread(this, "Dgclock"); timer.start(); } } public void run() { while (timer != null) { try { timer.sleep(1000); }catch (InterruptedException e) { break; } repaint(); } timer=null; } public void paintApplet() { int i, j, k, x; Date now=new Date(); int hour, minute, second; String hr, min, sec, today; Graphics gc; if (TimeDiff != 0L) { now.setTime(now.getTime()+TimeDiff); } hr=formatDate(TimeFormat,now); min=formatDate("%M",now); sec=formatDate("%S",now); if (ShowDate == true) { today=formatDate("%d",now); } else today=""; if (tracker.statusID(0,true) == MediaTracker.COMPLETE) { //if (offset == 4) if (use_frame == true) { gc=buf_image.getGraphics(); //draw the frame gc.clipRect(0,0,base_width,base_height); gc.drawImage(big_image,0,0,this); } //draw the hour digit images for (i=0; i < hr.length(); i++) { gc=buf_image.getGraphics(); x=offset+(i*bdigit_width); gc.clipRect(x,offset,15,20); x=x-100-(hr.charAt(i)-'0')*bdigit_width; gc.drawImage(big_image,x,offset,null); } // draw the colon image gc=buf_image.getGraphics(); x=offset+i*bdigit_width; gc.clipRect(x,offset,bdigit_width,bdigit_height); x=x-250; gc.drawImage(big_image,x,offset,null); i++; //draw the minute images for (j=0; j < min.length(); j++) { gc=buf_image.getGraphics(); x=offset+(i*bdigit_width); gc.clipRect(x,offset,15,20); x=x-100-(min.charAt(j)-'0')*bdigit_width; gc.drawImage(big_image,x,offset,null); i++; } // draw the second images for (j=0; j < sec.length(); j++) { gc=buf_image.getGraphics(); x=offset+(i*bdigit_width)+(j*sdigit_width); gc.clipRect(x,offset,sdigit_width,sdigit_height); x=x-100-(sec.charAt(j)-'0')*sdigit_width; gc.drawImage(big_image,x,offset-bdigit_height,null); } if (ShowDate == true) { for(k=0; k < today.length(); k++) { gc=buf_image.getGraphics(); x=offset+(i*bdigit_width)+(k*sdigit_width); gc.clipRect(x,offset+sdigit_height+1, sdigit_width,sdigit_height); x=x-100-(today.charAt(k)-'0')*sdigit_width; gc.drawImage(big_image,x, offset+sdigit_height-bdigit_height,null); } } } } public void update(Graphics g) { if (tracker.statusID(0,true) == MediaTracker.COMPLETE) { if (buf_image != null) { if (use_frame == false) { Graphics gc=buf_image.getGraphics(); gc.setColor(bg_color); gc.fillRect(0,0,base_width,base_height); } paintApplet(); g.drawImage(buf_image,0,0,this); } else { g.clearRect(0,0,base_width,base_height); } } else { g.drawString("Loading..",10,15); } } // Left Pad a number // taken from Clock2 by Per Reedtz Thomsen/Rachel Gollub private String padElement(int expr, char padChar) { String result = ""; // I'm just padding 2 digit numbers if (expr < 10) result = result.concat(String.valueOf(padChar)); result = result.concat(String.valueOf(expr)); return(result); } // Format a date according to the formatting string. // taken from Clock2 by Per Reedtz Thomsen/Rachel Gollub private String formatDate(String fmt, Date d) { String formattedDate = ""; // Retrieve the specific date information int hour = d.getHours(); int minute = d.getMinutes(); int second = d.getSeconds(); int monthDay = d.getDate(); int US_Hour = hour < 13 ? hour : hour - 12; // Loop through the format string for(int i = 0; i < fmt.length(); i++) { if (fmt.charAt(i) == '%') // We've hit a formatting command... { i++; // Move past the '%' sign // Figure out the format. switch (fmt.charAt(i)) { case 'H': // Hour -- 00 to 23 formattedDate = formattedDate.concat(padElement(hour, '0')); break; case 'I': // Hour -- 01 to 12 formattedDate = formattedDate.concat(padElement(US_Hour, '0')); //formattedDate=formattedDate.concat(String.valueOf(US_Hour)); break; case 'M': // Minutes -- 00 to 59 formattedDate = formattedDate.concat(padElement(minute, '0')); break; case 'd': // 2 digit month number formattedDate = formattedDate.concat(padElement(monthDay, '0')); break; case 'S': // Second -- 00 to 61 (leap seconds) formattedDate = formattedDate.concat(padElement(second, '0')); break; default: formattedDate = formattedDate.concat("??"); break; } } else // A regular character { formattedDate = formattedDate.concat(String.valueOf(fmt.charAt(i))); } } // end for return(formattedDate); } public void stop() { if (timer != null) { timer.stop(); timer=null; } } public boolean handleEvent(Event evt) { switch(evt.id) { case Event.MOUSE_DOWN: { if (suspended) { timer.resume(); } else { //Print ("Suspending.."); timer.suspend(); } suspended = !suspended; break; } case Event.MOUSE_MOVE: { if (tracker.statusID(0,true) != MediaTracker.COMPLETE) { showStatus("Loading image...please wait!"); } else { if (suspended == false) { if (ShowStatus == true) showStatus("Dgclock 2.3 by ma_muquit@fccc.edu"); else { String tz=getParameter("TZ"); if (tz != null) showStatus(tz); else showStatus("your time"); } } } break; } } return true; } /* public void Print(String str) { System.out.println(str); } */ } // change a color of the image class ColorFilter extends RGBImageFilter { Color fgc, bgc; public ColorFilter(Color fg,Color bg) { fgc=fg; bgc=bg; canFilterIndexColorModel=true; } public int filterRGB(int x,int y,int rgb) { int r=(rgb >> 16) & 0xff; int g=(rgb >> 8) & 0xff; int b=(rgb >> 0) & 0xff; int fg_r=fgc.getRed(); int fg_g=fgc.getGreen(); int fg_b=fgc.getBlue(); int bg_r=bgc.getRed(); int bg_g=bgc.getGreen(); int bg_b=bgc.getBlue(); //System.out.println("bg r,g,b=" + bg_r + "," + bg_g + "," + bg_b); //change foreground if ((r == 0) && (g == 255) && (b == 255)) { r=fg_r; g=fg_g; b=fg_b; if ((r == 0) && (g == 0) && (b ==0)) { r=g=b=1; } //System.out.println("fg r,g,b=" + r + "," + g + "," + b); } //change background if ((r == 0) && (g == 0) && (b == 0)) { r=bg_r; g=bg_g; b=bg_b; } return (rgb & 0xff000000) | (r << 16) | (g << 8) | (b << 0); } } 说明:（1）默认24小时显示，即： 如果采用12小时制，用如下参数： （2）参数中，如果设成yes，将鼠标放在时钟上在状态栏显示作者的有关信息。 （3）设置参数改变背景色和前景色，可以使用16进制的颜色： 从如下颜色选取： red,green,blue,cyan, magenta, yellow,orange, pink,black,white。 （4）是设置时区，中国在"东八区"，设成GMT+0800

忽然意识到java很棒！