java - Applet 无法在 html 页面上加载

Question

我有这个小程序，但我不明白为什么它没有在 html 页面上加载。我已在 java.policy 文件中添加了完全权限。我使用 NetBeans Applet 输出中的默认 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();

如果我是小程序在互联网上时的用户，这将导致 JRE 搜索相对于我的 PC 上当前用户目录的文件，无论是该目录还是缓存FF 的。无论哪种情况，它都不会通过名称 back2.png 定位图像。

因为担心听起来像循环剪辑:

• 应通过 URL 访问用于小程序的资源(图标、背景图像、帮助文件等)。
• 只要资源位于运行时类路径上，或者与代码库或文档库位于同一服务器上，小程序就不需要信任来访问这些资源。

进一步

I have added full permissions in java.policy file.

这毫无意义。除非您控制要运行它的每台计算机，否则它在部署时将无法工作。如果一个小程序需要在一般环境中得到信任，就需要对其进行数字签名。您不妨在构建应用程序时对其进行签名。

cant figure out why it doesnt load on html page.

将 Java 控制台配置为在加载小程序时打开会很有帮助。 Java 控制面板的最后一个选项卡中有一个可对其进行配置的设置。