我在测试二十一点 java 代码时遇到问题，这是以下代码：
package view;
/*
////In this applet, the user plays a game of Blackjack. The
////computer acts as the dealer. The user plays by clicking
////"Hit!" and "Stand!" buttons.
////The programming of this applet assumes that the applet is
////set up to be about 466 pixels wide and about 346 pixels high.
////That width is just big enough to show 2 rows of 5 cards.
////The height is probably a little bigger than necessary,
////to allow for variations in the size of buttons from one platform
////to another.
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import model.Card;
import model.Deck;
import model.Hand;
public class GUI21 extends JApplet {
public void init() {
// The init() method creates components and lays out the applet.
// A BlackjackCanvas occupies the CENTER position of the layout.
// On the bottom is a panel that holds three buttons. The
// BlackjackCanvas object listens for events from the buttons
// and does all the real work of the program.
setBackground( new Color(130,50,40) );
BlackjackCanvas board = new BlackjackCanvas();
getContentPane().add(board, BorderLayout.CENTER);
JPanel buttonPanel = new JPanel();
buttonPanel.setBackground( new Color(220,200,180) );
getContentPane().add(buttonPanel, BorderLayout.SOUTH);
JButton hit = new JButton( "Hit!" );
hit.addActionListener(board);
buttonPanel.add(hit);
JButton stand = new JButton( "Stand!" );
stand.addActionListener(board);
buttonPanel.add(stand);
JButton newGame = new JButton( "New Game" );
newGame.addActionListener(board);
buttonPanel.add(newGame);
} // end init()
public Insets getInsets() {
// Specify how much space to leave between the edges of
// the applet and the components it contains. The background
// color shows through in this border.
return new Insets(3,3,3,3);
}
// --- The remainder of this class consists of a nested class ---
class BlackjackCanvas extends JPanel implements ActionListener {
// A nested class that displays the card game and does all the work
// of keeping track of the state and responding to user events.
Deck deck; // A deck of cards to be used in the game.
Hand dealerHand; // Hand containing the dealer's cards.
Hand playerHand; // Hand containing the user's cards.
String message; // A message drawn on the canvas, which changes
// to reflect the state of the game.
boolean gameInProgress; // Set to true when a game begins and to false
// when the game ends.
Font bigFont; // Font that will be used to display the message.
Font smallFont; // Font that will be used to draw the cards.
BlackjackCanvas() {
// Constructor. Creates fonts and starts the first game.
setBackground( new Color(0,120,0) );
smallFont = new Font("SansSerif", Font.PLAIN, 12);
bigFont = new Font("Serif", Font.BOLD, 14);
doNewGame();
}
public void actionPerformed(ActionEvent evt) {
// Respond when the user clicks on a button by calling
// the appropriate procedure. Note that the canvas is
// registered as a listener in the GUI21 class.
String command = evt.getActionCommand();
if (command.equals("Hit!"))
doHit();
else if (command.equals("Stand!"))
doStand();
else if (command.equals("New Game"))
doNewGame();
}
void doHit() {
// This method is called when the user clicks the "Hit!" button.
// First check that a game is actually in progress. If not, give
// an error message and exit. Otherwise, give the user a card.
// The game can end at this point if the user goes over 21 or
// if the user has taken 5 cards without going over 21.
if (gameInProgress == false) {
message = "Click \"New Game\" to start a new game.";
repaint();
return;
}
playerHand.addCard( deck.takeCardfromDeck() );
if ( playerHand.getScore() > 21 ) {
message = "You've busted! Sorry, you lose.";
gameInProgress = false;
}
else if (playerHand.getScore() == 5) {
message = "You win by taking 5 cards without going over 21.";
gameInProgress = false;
}
else {
message = "You have " + playerHand.getScore() + ". Hit or Stand?";
}
repaint();
}
void doStand() {
// This method is called when the user clicks the "Stand!" button.
// Check whether a game is actually in progress. If it is,
// the game ends. The dealer takes cards until either the
// dealer has 5 cards or more than 16 points. Then the
// winner of the game is determined.
if (gameInProgress == false) {
message = "Click \"New Game\" to start a new game.";
repaint();
return;
}
gameInProgress = false;
while (dealerHand.getScore() <= 16 && dealerHand.getCardsinHand() < 5)
dealerHand.addCard( deck.takeCardfromDeck() );
if (dealerHand.getScore() > 21)
message = "You win! Dealer has busted with " + dealerHand.getCardsinHand() +".";
else if (dealerHand.getScore() == 5)
message = "Sorry, you lose. Dealer took 5 cards without going over 21.";
else if (dealerHand.getScore() > playerHand.getScore())
message = "Sorry, you lose, " + dealerHand.getScore()
+ " to " + playerHand.getScore() + ".";
else if (dealerHand.getScore() == playerHand.getScore())
message = "Sorry, you lose. Dealer wins on a tie.";
else
message = "You win, " + playerHand.getScore()
+ " to " + dealerHand.getScore() + "!";
repaint();
}
void doNewGame() {
// Called by the constructor, and called by actionPerformed() if
// the use clicks the "New Game" button. Start a new game.
// Deal two cards to each player. The game might end right then
// if one of the players had blackjack. Otherwise, gameInProgress
// is set to true and the game begins.
if (gameInProgress) {
// If the current game is not over, it is an error to try
// to start a new game.
message = "You still have to finish this game!";
repaint();
return;
}
deck = new Deck(); // Create the deck and hands to use for this game.
dealerHand = new Hand();
playerHand = new Hand();
deck.shuffle();
dealerHand.addCard( deck.takeCardfromDeck() ); // Deal two cards to each player.
dealerHand.addCard( deck.takeCardfromDeck() );
playerHand.addCard( deck.takeCardfromDeck() );
playerHand.addCard( deck.takeCardfromDeck() );
if (dealerHand.getScore() == 21) {
message = "Sorry, you lose. Dealer has Blackjack.";
gameInProgress = false;
}
else if (playerHand.getScore() == 21) {
message = "You win! You have Blackjack.";
gameInProgress = false;
}
else {
message = "You have " + playerHand.getScore() + ". Hit or stand?";
gameInProgress = true;
}
repaint();
} // end newGame();
public void paintComponent(Graphics g) {
// The paint method shows the message at the bottom of the
// canvas, and it draws all of the dealt cards spread out
// across the canvas.
super.paintComponent(g); // fill with background color.
g.setFont(bigFont);
g.setColor(Color.green);
g.drawString(message, 10, getSize().height - 10);
// Draw labels for the two sets of cards.
g.drawString("Dealer's Cards:", 10, 23);
g.drawString("Your Cards:", 10, 153);
// Draw dealer's cards. Draw first card face down if
// the game is still in progress, It will be revealed
// when the game ends.
g.setFont(smallFont);
if (gameInProgress)
drawCard(g, null, 10, 30);
else
drawCard(g, dealerHand.getCard(0), 10, 30);
for (int i = 1; i < dealerHand.getCardsinHand(); i++)
drawCard(g, dealerHand.getCard(i), 10 + i * 90, 30);
// Draw the user's cards.
for (int i = 0; i < playerHand.getCardsinHand(); i++)
drawCard(g, playerHand.getCard(i), 10 + i * 90, 160);
} // end paint();
void drawCard(Graphics g, Card card, int x, int y) {
// Draws a card as a 80 by 100 rectangle with
// upper left corner at (x,y). The card is drawn
// in the graphics context g. If card is null, then
// a face-down card is drawn. (The cards are
// rather primitive.)
if (card == null) {
// Draw a face-down card
g.setColor(Color.blue);
g.fillRect(x,y,80,100);
g.setColor(Color.white);
g.drawRect(x+3,y+3,73,93);
g.drawRect(x+4,y+4,71,91);
}
else {
g.setColor(Color.white);
g.fillRect(x,y,80,100);
g.setColor(Color.gray);
g.drawRect(x,y,79,99);
g.drawRect(x+1,y+1,77,97);
if (card.getSuit() == card.getSuit() || card.getSuit() == card.getSuit())
g.setColor(Color.red);
else
g.setColor(Color.black);
g.drawString(card.toSymbol(), x + 10, y + 30);
g.drawString("of", x+ 10, y + 50);
g.drawString(card.toSymbol(), x + 10, y + 70);
} // end drawCard()
} // end nested class BlackjackCanvas
}
} // end class HighLowGUI
但是，每当我测试它时，我都会收到以下错误：
Exception in thread "AWT-EventQueue-1" java.util.UnknownFormatConversionException: Conversion = 'i'
at java.util.Formatter$FormatSpecifier.conversion(Unknown Source)
at java.util.Formatter$FormatSpecifier.<init>(Unknown Source)
at java.util.Formatter.parse(Unknown Source)
at java.util.Formatter.format(Unknown Source)
at java.util.Formatter.format(Unknown Source)
at java.lang.String.format(Unknown Source)
at model.Card.toSymbol(Card.java:38)
at view.GUI21$BlackjackCanvas.drawCard(GUI21.java:266)
at view.GUI21$BlackjackCanvas.paintComponent(GUI21.java:232)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JLayeredPane.paint(Unknown Source)
at javax.swing.JComponent.paintChildren(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at java.awt.GraphicsCallback$PaintCallback.run(Unknown Source)
at sun.awt.SunGraphicsCallback.runOneComponent(Unknown Source)
at sun.awt.SunGraphicsCallback.runComponents(Unknown Source)
at java.awt.Container.paint(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.seqPaintDirtyRegions(Unknown Source)
at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$000(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.awt.EventQueue$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
任何建议都会很棒，谢谢。