這個 MyApplet.java 有許多個可以讓你很容易處理圖片和聲音的函數, 只要你 extends MyApplet 就可以使用, 那些寫 static 的函數則可以不必 extends MyApplet 就可使用, 當然要寫 MyApplet. 開頭, 例如 MyApplet.newCodeBase( ) 注意所有 "new" 開頭的函數都只能用在 Java Application, 請先測試以下小程式 gga.java 再研究 MyApplet.java //gga.java --- test function in MyApplet.java import java.net.*; // URL 在 java.net.*; class gga { public static void main(String yy[ ]) { URL g = MyApplet.newCodeBase( ); String y = "" + g; y = y.replace("file:", ""); // 去掉 "file:" if any System.out.println("Your current directory is " + y); } // main( }// class // javac gga.java // java gga /////////////////// 01 //MyApplet.java -- @CopyLeft by tsaiwn@csie.nctu.edu.tw 02 // provide some good utility functions for Applets 03 // as long as some static utility functions for Applications 04 //All functions begins with "new" are for Application only 05 /// 06 import java.applet.*; 07 import java.awt.*; import java.awt.image.*; 08 import java.io.*; import java.net.*; 09 import javax.swing.*; 10 11 public class MyApplet extends Applet { 12 13 public MyApplet( ) { // nothing to do 14 } // 裡面沒寫等於寫了 super( ); 15 16 public void start( ) { 17 Class o = getClass( ); // 抓出你的 class 名稱 18 printf("MyApplet_start: my class name from getclass( ) = "+ o +"\n"); 19 super.start( ); // 做 Applet 的 start( ); 20 } 21 22 /// newCodeBase() --- get the user's current working Directory 23 static public URL newCodeBase( ) { // for Application 24 URL codeBase = null; 25 try { 26 codeBase = new URL("file:" + System.getProperty("user.dir") + "/"); 27 } catch ( Exception e ) { 28 // maybe it is an Applet, use getCodeBase() or getDocumentBase() 29 /// but they only works in an Applet hosted in a Browser 30 } 31 return codeBase; 32 } 33 /// same as newCodeBase() --- get the user's current working Directory 34 static public URL getMyCodeBase( ) { // for Application 35 return newCodeBase( ); 36 } 37 /// same as newCodeBase() --- get the user's current working Directory 38 static public URL getCWD( ) { // get Current Working Directory 39 return newCodeBase( ); 40 } 41 42 /// getPath, only works for Applet 43 public URL getPath(String filename) { 44 URL url = null; 45 try { 46 Toolkit tkt = Toolkit.getDefaultToolkit( ); 47 Class me = getClass( ); // get The class is running 48 url = me.getResource(filename); // for Applet 49 } catch ( Exception e2) {;} // ignore 50 return url; 51 } 52 /// newGetPath, static version of getPath 53 static public URL newGetPath(String filename) { 54 URL url = null; 55 try { 56 Toolkit tkt = Toolkit.getDefaultToolkit( ); 57 url = new URL( newCodeBase( ) + filename ); 58 } catch ( Exception e2) {;} // ignore 59 return url; 60 } 61 62 /// getAudioBoth(filename) --- get AudioClip from Application or Applet 63 public AudioClip getAudioBoth(String filename) { 64 AudioClip audio = null; 65 try { // try Application first 66 audio = newAudio(newCodeBase( ), filename); 67 } catch (Exception e) { // then try Applet 68 } 69 if(audio == null) { // try Applet 70 try{ audio = getAudioClip(getCodeBase( ), filename); 71 } catch ( Exception e ) {;} 72 } 73 return audio; // send it back anyway 74 } // getAudioBoth 75 76 /// newAudio(filename) --- get AudioClip from an Application (not Applet) 77 static public AudioClip newAudioStatic(String filename) { 78 AudioClip audio = null; 79 try { 80 audio = newAudio(newCodeBase( ), filename); 81 } catch (Exception e) { ; } 82 return audio; 83 } // newAudio(filename) 84 /// 85 public AudioClip newAudioBoth(String filename) { 86 AudioClip audio = null; 87 try { // 2004/06/08 88 Toolkit tkt = Toolkit.getDefaultToolkit( ); 89 Class me = getClass( ); // get The class is running 90 URL url = me.getResource(filename); 91 audio = Applet.newAudioClip( url ); 92 } catch (Exception e) { ; } 93 return audio; 94 } // newAudioBoth(filename) 95 /// newAudio(url, filename) 96 static public AudioClip newAudio(URL base, String filename) { 97 AudioClip audio = null; 98 try{ audio = Applet.newAudioClip( new URL(base+ filename) ); 99 } catch ( Exception e ) { 100 // maybe it is an Applet, you should use getAudioClip(URL url) 101 // .. or getAudioClip(URL url, String filename) in Applet 102 } 103 return audio; 104 } // newAudio(url, filename) 105 /// newAudio(url) --- get AudioClip from an Application (not Applet) 106 static public AudioClip newAudio(URL url) { 107 AudioClip audio = null; 108 try{ audio = Applet.newAudioClip( url ); // JDK1.2 static method 109 } catch ( Exception e ) {;} 110 return audio; 111 } // newAudio(url) 112 113 /// get Image from a local file --- for Application (not Applet) 114 // Note that this is a static methods 115 // usage: MyApplet.newImage("your_image_filename_path"); 116 static public Image newImage(String filename) { 117 Image image = null; 118 try{ 119 Toolkit tkt = Toolkit.getDefaultToolkit( ); 120 image = tkt.getImage(filename); //for application only 121 // image = getImage(getCodeBase( ), filename); //for Applet 122 } catch ( Exception e ) { image = null;} 123 return image; 124 } // newImage(filename) 125 static public Image newGetImage(String filename) { 126 return newImage(filename); 127 } // newGetImage 128 static public Image getMyImage(String filename) { 129 return newImage(filename); 130 } // getMyImage(filename) 131 132 /// get Image from a URL 133 static public Image newImage(URL url) { 134 Image image = null; 135 try{ Toolkit tkt = Toolkit.getDefaultToolkit( ); 136 image = tkt.getImage(url); //for application only 137 } catch ( Exception e ) {;} 138 return image; 139 } // newImage(url) 140 static public Image newGetImage(URL url) { 141 return newImage(url); 142 } // newGetImage(url) 143 144 /// @@@ 寫個 function to createMyCursor 方便使用@@@ 145 /// Application please uses Cursor mycsr = newMyCursor(filename); 146 /// Applet please uses Cursor mycsr = createMyCursor(filename); 147 /// 148 /// now, this static method is for Application only 149 static public java.awt.Cursor newMyCursor(String filename) throws 150 IndexOutOfBoundsException { 151 java.awt.Cursor cursor = null; 152 try{ 153 Toolkit tkt = Toolkit.getDefaultToolkit( ); 154 Image csrImg = tkt.getImage(filename); //for application 155 cursor = tkt.createCustomCursor(csrImg, new Point(1,1), filename); 156 } catch ( Exception e ) { // if error, give him an Hand Cursor 157 cursor = new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR); 158 } 159 return cursor; 160 } // createMyCursor 161 162 // now, the following is for Applet, not a static method 163 public java.awt.Cursor createMyCursor(String filename) throws 164 IndexOutOfBoundsException { 165 java.awt.Cursor cursor = null; 166 try{ 167 Toolkit tkt = Toolkit.getDefaultToolkit( ); 168 //Image csrImg = tkt.getImage(filename); //for application 169 Image csrImg = getImage(getCodeBase( ), filename); //for Applet 170 cursor = tkt.createCustomCursor(csrImg, new Point(1,1), filename); 171 } catch ( Exception e ) { 172 cursor = new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR); 173 } 174 return cursor; 175 } // createMyCursor 176 177 public java.awt.Cursor createMyCursorBoth(String filename) throws 178 IndexOutOfBoundsException { 179 java.awt.Cursor cursor = null; 180 try{ 181 Toolkit tkt = Toolkit.getDefaultToolkit( ); 182 Class me = getClass( ); // get The class is running 183 URL url = me.getResource(filename); 184 Image csrImg = tkt.getImage( url ); // works for Application+Applet 185 cursor = tkt.createCustomCursor(csrImg, new Point(1,1), filename); 186 } catch ( Exception e ) { 187 cursor = new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR); 188 } 189 return cursor; 190 } // createMyCursor 191 192 // for both Application and Applet 193 static public java.awt.Cursor createMyCursor(Image image) throws 194 IndexOutOfBoundsException { 195 java.awt.Cursor cursor = null; 196 try{ 197 Toolkit tkt = Toolkit.getDefaultToolkit( ); 198 cursor = tkt.createCustomCursor(image, new Point(1,1), "cursor"); 199 } catch ( Exception e ) { 200 cursor = new java.awt.Cursor(java.awt.Cursor.HAND_CURSOR); 201 } 202 return cursor; 203 } // createMyCursor 204 205 JLabel createLabelWithPicture(String filename) { 206 return createLabelWithPicture(filename, "", 207 javax.swing.SwingConstants.TRAILING); 208 } 209 JLabel createLabelWithPicture(String filename, String caption) { 210 return createLabelWithPicture(filename, caption, 211 javax.swing.SwingConstants.TRAILING); 212 } 213 JLabel createLabelWithPicture(String filename, String caption, 214 int alignment ) { 215 JLabel ans = null; 216 ImageIcon icon = null; 217 try { 218 Image image = myGetImageBoth(filename); 219 icon = new ImageIcon( image ); 220 ans = new JLabel(caption, icon, alignment); 221 ans.setVerticalTextPosition( 222 javax.swing.SwingConstants.BOTTOM); 223 ans.setHorizontalTextPosition( 224 javax.swing.SwingConstants.CENTER); 225 } catch (Exception e) { 226 try { if(ans==null) ans = new JLabel(caption); 227 } catch (Exception e2) {;} 228 } 229 return ans; 230 } 231 232 /// some int constants used in the following functions 233 final static int TEXT_VP = javax.swing.SwingConstants.BOTTOM; 234 final static int TEXT_HP = javax.swing.SwingConstants.CENTER; 235 final static int IMG_V_ALIGN = javax.swing.SwingConstants.TOP; 236 final static int IMG_H_ALIGN = javax.swing.SwingConstants.LEFT; 237 JButton createButtonWithPicture(String filename) { 238 return createButtonWithPicture(filename, "", 239 TEXT_VP, TEXT_HP, IMG_V_ALIGN, IMG_H_ALIGN ); 240 } 241 JButton createButtonWithPicture(String filename, String caption) { 242 return createButtonWithPicture(filename, caption, 243 TEXT_VP, TEXT_HP, IMG_V_ALIGN, IMG_H_ALIGN ); 244 } 245 JButton createButtonWithPicture(String filename, String caption, 246 int textVP) { 247 return createButtonWithPicture(filename, caption, 248 textVP, TEXT_HP, IMG_V_ALIGN, IMG_H_ALIGN ); 249 } 250 JButton createButtonWithPicture(String filename, String caption, 251 int textVP, int textHP ) { 252 return createButtonWithPicture(filename, caption, 253 textVP, textHP, IMG_V_ALIGN, IMG_H_ALIGN ); 254 } 255 JButton createButtonWithPicture(String filename, String caption, 256 int textVP, int textHP, int imgVAlign ) { 257 return createButtonWithPicture(filename, caption, 258 textVP, textHP, imgVAlign, IMG_H_ALIGN ); 259 } 260 JButton createButtonWithPicture(String filename, String caption, 261 int textVP, int textHP, int imgVAlign, int imgHAlign ) { 262 JButton ans = null; 263 ImageIcon icon = null; 264 try { 265 Image image = myGetImageBoth(filename); 266 icon = new ImageIcon( image ); 267 ans = new JButton(caption, icon); 268 ans.setVerticalTextPosition(textVP); 269 ans.setHorizontalTextPosition(textHP); 270 ans.setVerticalAlignment(imgVAlign); 271 ans.setHorizontalAlignment(imgHAlign); 272 } catch (Exception e) { 273 try { if(ans==null) ans = new JButton(caption); 274 } catch (Exception e2) {;} 275 } 276 return ans; 277 } 278 279 Image getImageBoth(String filename) { 280 return myGetImageBoth( filename); 281 } 282 Image myGetImageBoth(String filename) { 283 Image image = null; 284 try { // Application 中讀取 Image 方法與 Applet 中不同 285 image = newImage(filename); //try Application first 286 //println("MyApplet got image=" + image); 287 } catch (Exception e) { image=null; // then, try Applet 288 } // try .. catch 289 if(image==null) { 290 try { // try Applet, Applet use different method 291 image = getImage(new URL( getCodeBase()+ filename)); 292 } catch (Exception e) { image = null;} 293 } //if 294 try { // ok, now the last way I can try 295 Toolkit tkt = Toolkit.getDefaultToolkit( ); 296 Class me = getClass( ); // get The class which is running 297 URL url = me.getResource(filename); 298 image = tkt.getImage( url ); // works for both Application+Applet 299 } catch (Exception e) { image = null; } // sorry, I have no way 300 return image; 301 } // myGetImageBoth 302 303 /// play an audio file (for Application only) 304 static AudioClip newPlayFile(String filename) { 305 AudioClip song = null; 306 try { 307 URL base = newCodeBase(); 308 song = Applet.newAudioClip(new URL(base+filename)); 309 song.play( ); 310 } catch (Exception e) { return song; } // ignore any error 311 try { Thread.sleep(358); } catch (Exception e) {;} 312 return song; 313 } 314 315 public AudioClip playFile(String filename) { 316 AudioClip song = null; 317 try { 318 //song = getAudioClip(getCodeBase(), filename); // Applet's 318 song = newAudioBoth(filename); // both OK 319 song.play( ); 320 } catch (Exception e) { return song; } // Let the caller know 321 try { Thread.sleep(358); } catch (Exception e) {;} 322 return song; 323 } 324 325 /// 326 /// a utility to invoke the Task Manager (taskmgr) of Windows system 327 // usage: MyApplet.runTaskManager( ); 328 static void runTaskManager( ) { // only works for Application only 329 printf("Try to run the Task Manager (taskmgr ) \n" ); 330 try { 331 try { // 注意格式, 因字串中含有 " 雙引號 " 332 Runtime.getRuntime().exec( 333 "cmd /c \"taskmgr" + "\" " ); 334 } catch (Exception e95){ 335 // to do : how to do on Win95/98 ? 336 } // Win95/98 ? 337 } catch (Exception e) {; } 338 } // run taskmgr 339 340 341 /// 342 /// some println/print utilities for MyApplet, note that this is not static 343 /// some println/print utilities for convinent 344 static public void println(String s) { 345 try { System.out.println(s); 346 } catch (Exception e) {;} // ignore any error 347 } 348 static public void print(String s) { // not static 349 try { System.out.print(s); 350 } catch (Exception e) {;} // ignore any error 351 } 352 /// some printErr utilities 353 static public void printErr(String s) { 354 try { System.err.println(s); System.err.flush( ); 355 } catch (Exception e) {;} // ignore any error 356 } 357 static public void printf(String s) { 358 try { System.out.print(s); 359 } catch (Exception e) {;} // ignore any error 360 } 361 public static void printf(long n) throws IOException { 362 System.out.print(""+n); 363 } 364 public static void printf(int n) throws IOException { 365 System.out.print(""+n); 366 } 367 /// print n as w columns width 368 public static void printf(short n, int w) { 369 printf((long)n, w); // print n as w columns 370 } 371 public static void printf(int n, int w) { 372 printf((long)n, w); 373 } 374 public static void printf(long n, int w) { 375 long tmp = 1; // print n as w columns 376 long nabs = n; if(n<0) {nabs = -nabs; --w; } // ensure positive 377 for(;;) { 378 tmp *= 10; 379 if(tmp > nabs) break; 380 --w; // w is the expected Width (number of digits) 381 } 382 try { 383 for(;;) { 384 if(--w <= 0) break; 385 System.out.print(" "); // necessary leading space 386 } 387 System.out.print(""+n); 388 } catch (Exception e) {;} // ignore any error 389 } 390 391 public void flush( ) { 392 try { System.out.flush( ); 393 } catch (Exception e) {;} // ignore any error 394 } 395 396 static public void fflush( ) { 397 try { System.out.flush( ); 398 } catch (Exception e) {;} // ignore any error 399 } 400 401 static public void beep( ) { 402 java.awt.Toolkit.getDefaultToolkit( ).beep( ); 403 } 404 405 /// a main program to test my printf functions 406 public static void main(String[]p) throws IOException { 407 printf("= This MyApplet.java provides many utility functions =\n"); 408 printf("=="); printf(1, 1); printf("==\n"); 409 printf("=="); printf(2, 2); printf("==\n"); 410 printf("=="); printf(3, 3); printf("==\n"); 411 printf("=="); printf(11, 1); printf("==\n"); 412 printf("=="); printf(12, 2); printf("==\n"); 413 printf("=="); printf(13, 3); printf("==\n"); 414 printf("=="); printf(111, 1); printf("==\n"); 415 printf("=="); printf(113, 3); printf("==\n"); 416 printf("=="); printf(115, 5); printf("==\n"); 417 printf("=="); printf(-11, 1); printf("==\n"); 418 printf("=="); printf(-12, 2); printf("==\n"); 419 printf("=="); printf(-13, 3); printf("==\n"); 420 printf("=="); printf(-15, 5); printf("==\n"); 421 printf("=="); printf(-116, 6); printf("==\n"); 422 try { 423 AudioClip sound = null; sound = newAudioStatic("laugh.au"); 424 if(sound != null) { sound.play( ); Thread.sleep(2588); } 425 } catch(Exception e) {;} 426 printf("Thank you!\n"); 427 for(int i=1; i <= 3; ++i) { 428 java.awt.Toolkit.getDefaultToolkit( ).beep( ); 429 try{ Thread.sleep(258);}catch(Exception e){;} // 0.258 second 430 } 431 System.exit(0); 432 } 433 } // class MyApplet 434 435 class PictureCanvas extends Canvas implements ImageObserver { 436 String filename = null; 437 String caption = null; 438 Image image = null; 439 public PictureCanvas(String filename) { 440 this(filename, ""); // call other Constructor 441 } 442 public PictureCanvas(String filename, String caption) { 443 this.filename = filename; 444 this.caption = caption; 445 try { 446 Toolkit tkt = Toolkit.getDefaultToolkit( ); 447 Class me = getClass( ); // get The class is running 448 URL url = me.getResource(filename); 449 image = tkt.getImage( url ); // works for both Application+Applet 450 } catch (Exception e) { ; } 451 repaint( ); 452 } 453 public void update(Graphics g) { 454 paint(g); // call paint directly without clear the panel 455 } 456 public void paint(Graphics g) { 457 int xpos = 12, ypos = 12; 458 if(image!=null) { 459 g.drawImage(image, 2, 2, this ); // Align left-upper corner 460 try { 461 xpos = image.getWidth(this)/4; 462 ypos = image.getHeight(this) - 24; 463 }catch(Exception e) {;} 464 } 465 if(caption != null) { 466 g.setFont(new Font("細明體", Font.PLAIN, 18) ); 467 g.setColor(Color.red); 468 g.drawString( caption, xpos, ypos ); 469 } 470 } // paint 471 } // PictureCanvas 472 473 class PicturePanel extends Panel { 474 String filename = null; 475 String caption = null; 476 Image image = null; 477 boolean wantResize = false; 478 public PicturePanel(String filename, boolean wantResize) { 479 this(filename, "", wantResize); // call other Constructor 480 } 481 public PicturePanel(String filename) { 482 this(filename, "", false); // call other Constructor 483 } 484 public PicturePanel(String filename, String caption) { 485 this(filename, caption, false); // call other Constructor 486 } 487 public PicturePanel(String filename, String caption, boolean w) { 488 this.wantResize = w; 489 this.filename = filename; 490 this.caption = caption; 491 try { 492 Toolkit tkt = Toolkit.getDefaultToolkit( ); 493 Class me = getClass( ); // get The class is running 494 //MyApplet. printf(" getClass() = " + me +"\n"); 495 URL url = me.getResource(filename); 496 image = tkt.getImage( url ); // works for both Application+Applet 497 // Only those Applets hosted in a Browser can obtain CodeBase 498 /// .. and DocumentBase using getCodeBase( ) and getDocumentBase( ) 499 /// .. Since this PicturePanel is not an Applet, the 500 /// method getCodeBase() doesn't work even you call it from an Applet 501 } catch (Exception e) { ; } 502 repaint( ); 503 } 504 public void update(Graphics g) { 505 paint(g); // call paint directly without clear the panel 506 } 507 public void paint(Graphics g) { 508 int xpos = 12, ypos = 12; 509 if(image!=null) { 510 int width = 0; 511 int height = 38; 512 try { 513 width = image.getWidth(this); // image's width 514 height = image.getHeight(this); 515 } catch (Exception e) {;} 516 if(wantResize) 517 try { 518 width = getSize().width; // current Panel's width 519 height = getSize().height; 520 } catch (Exception e) {;} 521 if(width == 0) 522 g.drawImage(image, 2, 2, this ); // Align left-upper corner 523 else 524 g.drawImage(image, 2, 2, width, height, this ); 525 // now paint the caption 526 try { 527 xpos = image.getWidth(this)/4; 528 ypos = image.getHeight(this) - 24; 529 }catch(Exception e) {;} 530 } 531 if(caption != null) { 532 g.setFont(new Font("細明體", Font.PLAIN, 18) ); 533 g.setColor(Color.red); 534 g.drawString( caption, xpos, ypos ); 535 } 536 } // paint 537 } // PicturePanel