java - 小程序未在 html 页面上加载

Question

我有这个小程序，但我不知道为什么它没有加载到 html 页面上。我在 java.policy 文件中添加了完全权限。我使用来自 NetBeans Applet 输出的默认 html 文件。

/* Hearts Cards Game with AI*/
import java.applet.Applet;
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Random;
import javax.swing.JOptionPane;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import java.awt.Graphics;
import java.awt.Image;
import java.security.AccessController;
import javax.swing.ImageIcon;
import javax.swing.*;
import javax.swing.JPanel;

public class Game extends JApplet implements MouseListener, Runnable {

    int initNoCards = 13;
    int width, height;
    boolean endGame = false;
    int turn = -1;
    int firstCard = 0;
    int firstTrick = 0;
    String leadingSuit = null;
    Cards leadingCard = null;
    Cards playCard = null;
    String startCard = "c2";
    Cards[] trickCards = new Cards[4];
    ArrayList<Cards>[] playerCards = new ArrayList[4];
    ArrayList<Cards>[] takenCards = new ArrayList[4];
    boolean heartsBroken = false;
    ArrayList<Cards> cards = new ArrayList<Cards>();

    String[] hearts = {"h2", "h3", "h4", "h5", "h6", "h7", "h8", "h9", "h10", "h12", "h13", "h14", "h15"};
    String queen = "s13";
    int cardHeight = 76;
    int cardWidth = 48;
    ArrayList<Rectangle> rectangles = new ArrayList<Rectangle>();
    int selectedCard = -1;
//set the background image
    Image backImage = new ImageIcon("deck\\back2.png").getImage();

    public void GetDataFromXML() {
        try {
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser saxParser = factory.newSAXParser();
            DefaultHandler handler = new DefaultHandler() {

                boolean name = false;
                boolean image = false;

                @Override
                public void startElement(String uri, String localName, String qName,
                        Attributes attributes) throws SAXException {
                    if (qName.equalsIgnoreCase("NAME")) {
                        name = true;
                    }
                    if (qName.equalsIgnoreCase("IMAGE")) {
                        image = true;
                    }
                }

                @Override
                public void endElement(String uri, String localName,
                        String qName) throws SAXException {
                }

                @Override
                public void characters(char ch[], int start, int length) throws SAXException {
                    String s = new String(ch, start, length);
                    if (name) {
                        cards.add(new Cards(s));
                        name = false;
                    }
                    if (image) {
                        image = false;
                    }
                }
            };
            saxParser.parse("deck\\deck.xml", handler);
        } catch (Exception e) {
        }
    }
    //function for comparing cards from same suite

    public boolean lowerThan(Cards c1, Cards c2) {
        int a, b;
        a = Integer.parseInt(c1.getName().substring(1));
        b = Integer.parseInt(c2.getName().substring(1));
        return a < b;
    }
//checks if a card is valid to play
    public boolean ValidMove(Cards c) {
        if (firstCard == 0) {
            if (c.getName().equals(startCard)) {
                firstCard = 1;
                return true;
            }
            return false;
        }
        boolean result = playerCards[turn].indexOf(c) >= 0;
        if (leadingSuit == null) {
            return result;
        }
        boolean found = false;
        for (int i = 0; i < playerCards[turn].size(); i++) {
            if (playerCards[turn].get(i).getName().charAt(0) == leadingSuit.charAt(0)) {
                found = true;
                break;
            }
        }
        if (!found) {
            boolean justHearts = true;
            for (int i = 0; i < playerCards[turn].size(); i++) {
                if (playerCards[turn].get(i).getName().charAt(0) != 'h') {
                    justHearts = false;
                    break;
                }
            }
            if (firstTrick == 0) {
                if (c.getName().equals(queen)) {
                    return false;
                }
                if (!justHearts && c.getName().charAt(0) == 'h') {
                    return false;
                }
            } else {
                if (c.getName().charAt(0) == 'h' && leadingSuit == null && !heartsBroken && !justHearts) {
                    return false;
                }
            }
        } else {
            if (c.getName().charAt(0) != leadingSuit.charAt(0)) {
                return false;
            }
        }
        return result;
    }

    @Override
    public void init() {
        GetDataFromXML();
        setSize(500, 500);
        width = super.getSize().width;
        height = super.getSize().height;
        setBackground(Color.white);
        addMouseListener(this);
        for (int i = 0; i < cards.size(); i++) {
            System.out.println(cards.get(i).getName());
            System.out.println(cards.get(i).getImage());
        }
        Shuffle();
    }

    public int GetTrickCount() {
        int count = 0;
        for (int i = 0; i < trickCards.length; i++) {
            if (trickCards[i] != null) {
                count++;
            }
        }
        return count;
    }

    public void ResetTrick() {
        for (int i = 0; i < trickCards.length; i++) {
            trickCards[i] = null;
        }
    }

    @Override
    public void run() {
        try {
            PlayTurn();
        } catch (InterruptedException ex) {
        }
    }

    public void start() {
        Thread th = new Thread(this);
        th.start();
    }
//function for shuffling cards and painting players cards
    public void Shuffle() {

        for (int i = 0; i < 4; i++) {
            playerCards[i] = new ArrayList<Cards>();
            takenCards[i] = new ArrayList<Cards>();
        }
        ArrayList<Cards> list = new ArrayList<Cards>();
        list.addAll(cards);
        Collections.shuffle(list);
        for (int i = 0; i < list.size(); i++) {
            System.out.print(list.get(i).getName() + " ");
        }
        //initializare liste carti
        for (int i = 0; i < 4; i++) {
            playerCards[i] = new ArrayList<Cards>();
            takenCards[i] = new ArrayList<Cards>();
            for (int j = 0; j < initNoCards; j++) {
                playerCards[i].add((list.get(j + i * initNoCards)));
                if (list.get(j + i * initNoCards).getName().equals(startCard)) {
                    turn = i;
                }
            }
            Collections.sort(playerCards[i], c);
            ShowCards(i);
        }
        for (int i = 0; i < playerCards[0].size() - 1; i++) {
            rectangles.add(new Rectangle((141 + 1) + 13 * i - 2, 350 + 1, 13 - 2, cardHeight - 1));
        }
        rectangles.add(new Rectangle((141 + 1) + 13 * 12 - 2, 350 + 1, cardWidth, cardHeight - 1));
        ShowPlayersCards();
    }
    Comparator<Cards> c = new Comparator<Cards>() {

        @Override
        public int compare(Cards o1, Cards o2) {
            if (o2.getName().charAt(0) != o1.getName().charAt(0)) {
                return o2.getName().charAt(0) - o1.getName().charAt(0);
            } else {
                int a, b;
                a = Integer.parseInt(o1.getName().substring(1));
                b = Integer.parseInt(o2.getName().substring(1));
                return a - b;
            }
        }
    };

    public void PlayTurn() throws InterruptedException {
        endGame = true;
        System.out.println("Its " + turn);
        for (int i = 0; i < 4; i++) {
            if (!playerCards[i].isEmpty()) {
                endGame = false;
            }
        }
        if (endGame) {
            System.out.println("Game over!");
            GetPlayersScore();
            return;
        }
        if (turn != 0) {
            Random r = new Random();
            int k = r.nextInt(playerCards[turn].size());
            Cards AIcard = playerCards[turn].get(k);
            while (!ValidMove(AIcard)) {
                k = r.nextInt(playerCards[turn].size());
                AIcard = playerCards[turn].get(k);
            }
            leadingCard = AIcard;
            playCard = AIcard;
        } else {
            System.out.println("\nIt is player's (" + turn + ") turn");
            System.out.println("Player (" + turn + ") enter card to play:");
            leadingCard = null;
            playCard = null;//new Cards(read);
            while (true) {
                if (playCard != null) {
                    break;
                }
                Thread.sleep(50);
            }
        }
        repaint();
        Thread.sleep(1000);
        repaint();
        if (playCard.getName().charAt(0) == 'h') {
            heartsBroken = true;
        }
        playerCards[turn].remove(playCard);
        trickCards[turn] = playCard;
        if (GetTrickCount() == 1)//setez leading suit doar pentru trickCards[0]
        {
            leadingSuit = GetSuit(playCard);
        }
        System.out.println("Leading suit " + leadingSuit);
        System.out.println("Player (" + turn + ") chose card " + playCard.getName() + " to play");
        ShowTrickCards();
        ShowPlayersCards();
        if (GetTrickCount() < 4) {
            turn = (turn + 1) % 4;
        } else {
            turn = GetTrickWinner();
            leadingSuit = null;
            firstTrick = 1;
            playCard = null;
            repaint();
        }
        PlayTurn();
    }

    public void ShowTrickCards() {
        System.out.println("Cards in this trick are:");
        for (int i = 0; i < 4; i++) {
            if (trickCards[i] != null) {
                System.out.print(trickCards[i].getName() + " ");
            }
        }
    }

    public String GetSuit(Cards c) {
        if (c.getName().contains("c")) {
            return "c";
        }
        if (c.getName().contains("s")) {
            return "s";
        }
        if (c.getName().contains("h")) {
            return "h";
        }
        if (c.getName().contains("d")) {
            return "d";
        }
        return null;
    }

    public String GetValue(Cards c) {
        String get = null;
        get = c.getName().substring(1);
        return get;
    }

    public int GetTrickWinner() {
        int poz = 0;
        for (int i = 1; i < 4; i++) {
            if (trickCards[poz].getName().charAt(0) == trickCards[i].getName().charAt(0) && lowerThan(trickCards[poz], trickCards[i]) == true) {
                poz = i;
            }
        }
        System.out.println("\nPlayer (" + poz + ") won last trick with card " + trickCards[poz].getName());
        ResetTrick();
        return poz;
    }

    public void ShowPlayersCards() {
        ShowCards(0);
        ShowCards(1);
        ShowCards(2);
        ShowCards(3);
    }

    public void GetPlayersScore() {
        GetScore(0);
        GetScore(1);
        GetScore(2);
        GetScore(3);
    }

    public void ShowCards(int player) {
        System.out.print("\nPlayer (" + player + ") cards: ");
        for (int i = 0; i < playerCards[player].size(); i++) {
            System.out.print(playerCards[player].get(i).getName() + " ");
        }
        System.out.println();
    }

    public int GetScore(int player) {
        int score = 0;
        for (int i = 0; i < takenCards[player].size(); i++) {
            for (int j = 0; j < hearts.length; j++) {
                if (takenCards[player].get(i).getName().equals(hearts[j])) {
                    score++;
                    break;
                }
            }
            if (takenCards[player].get(i).getName().equals(queen)) {
                score += 13;
            }
        }
        return score;

    }

    @Override
    public void paint(Graphics g) {
        g.drawImage(backImage, 0, 0, getWidth(), getHeight(), this);
        for (int i = 0; i < playerCards[0].size(); i++) {
            if (selectedCard == i) {
                g.drawImage(playerCards[0].get(i).getImage(), 141 + i * 13, 340, null);
            } else {
                g.drawImage(playerCards[0].get(i).getImage(), 141 + i * 13, 350, null);
            }
            if (trickCards[0] != null) {
                g.drawImage(trickCards[0].getImage(), 225, 250, 48, 76, null);
            }
            if (trickCards[1] != null) {
                g.drawImage(trickCards[1].getImage(), 177, 174, 48, 76, null);
            }
            if (trickCards[2] != null) {
                g.drawImage(trickCards[2].getImage(), 225, 98, 48, 76, null);
            }
            if (trickCards[3] != null) {
                g.drawImage(trickCards[3].getImage(), 273, 174, 48, 76, null);
            }
        }
    }

    @Override
    public void mouseClicked(MouseEvent e) {
        if (turn != 0) {
            return;
        }
        for (int i = 0; i < rectangles.size(); i++) {
            if (rectangles.get(i).contains(e.getPoint())) {
                if (i == selectedCard) {
                    if (ValidMove(playerCards[0].get(i))) {
                        selectedCard = -1;
                        rectangles.get(rectangles.size() - 2).width = rectangles.get(rectangles.size() - 1).width;
                        playCard = playerCards[0].get(i);
                        leadingCard = playCard;
                        rectangles.remove(rectangles.size() - 1);
                        trickCards[0] = playerCards[0].remove(i);
                    } else {
                        if (firstCard == 0) {
                            JOptionPane.showMessageDialog(this, "You have to play 2 of clubs!");
                        }
                    }
                } else {
                    selectedCard = i;
                    rectangles.get(i).y -= 10;
                }
                repaint();
                break;
            }
        }
    }

    @Override
    public void mousePressed(MouseEvent e) {
    }

    @Override
    public void mouseReleased(MouseEvent e) {
    }

    @Override
    public void mouseEntered(MouseEvent e) {
    }

    @Override
    public void mouseExited(MouseEvent e) {
    }
}

class Cards extends JPanel {

    private String name;
    private String image;
    private Image img;

    public Cards(String name) {
        super();
        this.name = name;
        this.image = "deck\\" + name + ".png";
        this.img = new ImageIcon(image).getImage();

    }

    public Cards() {
        super();
        this.name = null;
        this.image = null;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Image getImage() {
        return img;
    }

    public void setImage(String image) {
        this.image = image;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (!(obj instanceof Cards)) {
            return false;
        }
        Cards c = (Cards) obj;
        return name.equals(c.getName()) && image.equals(c.getImage());
    }

    @Override
    public int hashCode() {
        int hash = 7;
        hash = 31 * hash + (this.name != null ? this.name.hashCode() : 0);
        hash = 31 * hash + (this.image != null ? this.image.hashCode() : 0);
        return hash;
    }

    @Override
    public void paint(Graphics g) {
        g.drawImage(img, WIDTH, HEIGHT, this);
    }

    public boolean lowerThan(Cards c1, Cards c2) {
        int a, b;
        a = Integer.parseInt(c1.getName().substring(1));
        b = Integer.parseInt(c2.getName().substring(1));
        return a < b;
    }

    public int compareTo(Cards c) {
        if (c.getName().charAt(0) != name.charAt(0)) {
            return c.getName().charAt(0) - name.charAt(0);
        } else {
            int a, b;
            a = Integer.parseInt(name.substring(1));
            b = Integer.parseInt(c.getName().substring(1));
            return a - b;
        }
    }
}

HTML

<HTML>
<HEAD>
   <TITLE>Applet HTML Page</TITLE>
</HEAD>
<BODY>
<H3><HR WIDTH="100%">Applet HTML Page<HR WIDTH="100%"></H3>

<P>
<APPLET codebase="classes" code="Game.class" width=350 height=200></APPLET>
</P>

<HR WIDTH="100%"><FONT SIZE=-1><I>Generated by NetBeans IDE</I></FONT>
</BODY>
</HTML>

Answer 1

Image backImage = new ImageIcon("deck\\back2.png").getImage();

If I am the user of the applet when it is on the internet, the will cause the JRE to search for a File relative to the current user directory on my PC, either that or the cache of FF. In either case, it will not locate an image by the name of back2.png.

For fear of sounding like a looping Clip:

• Resources intended for an applet (icons, BG image, help files etc.) should be accessed by URL.
• An applet will not need trust to access those resources, so long as the resources are on the run-time class-path, or on the same server as the code base or document base.

Further

I have added full permissions in java.policy file.

This is pointless. It will not be workable at time of deployment unless you control every machine it is intended to run on. If an applet needs trust in a general environment, it needs to be digitally signed. You might as well sign it while building the app.

cant figure out why it doesnt load on html page.

Something that would assist greatly is to configure the Java Console to open when an applet is loaded. There is a setting in the last tab of the Java Control Panel that configures it.