本程序适用于java程序员巩固类与对象、文件读取、事件响应、awt包中各种工具的相关概念以及对逻辑能力的锻炼。源码联系上面公众号。
数据层
本实例需要从 .txt 文件中读取迷宫并绘制，所以先来实现文件读取IO类 MazeData.java，该程序在构造函数运行时将外部文件读入，并完成迷宫各种参数的初始化，注意规定了外部 .txt 文件的第一行两个数字分别代表迷宫的行数和列数。此外还提供了各类接口来读取或操作私有数据。
import java.io.BufferedInputStream; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.util.Scanner; public class MazeData { public static final char ROAD = ' '; public static final char WALL = '#'; private int N, M; // 高，宽（行，列） private char[][] maze; private int entranceX, entranceY; // 入口 private int exitX, exitY; // 出口 public boolean[][] visited; // 记录寻路过程某位置是否被访问过 public boolean[][] path; // 存储迷宫的解 public boolean showPath; // 是否打印系统提示的开关 public Position player; // 玩家所处位置 public MazeData(String filename){ if (filename == null) throw new IllegalArgumentException("Filename can not be null!"); Scanner scanner = null; try { File file = new File(filename); if (!file.exists()) throw new IllegalArgumentException("File " + filename + " doesn't exist"); FileInputStream fis = new FileInputStream(file); scanner = new Scanner(new BufferedInputStream(fis), "UTF-8"); // 读取第一行 String nmline = scanner.nextLine(); String[] nm = nmline.trim().split("\\s+"); // 正则 匹配任意空白字符 N = Integer.parseInt(nm[0]); M = Integer.parseInt(nm[1]); maze = new char[N][M]; visited = new boolean[N][M]; path = new boolean[N][M]; showPath = false; // 读取后续的N行 for (int i = 0; i < N; i ++){ String line = scanner.nextLine(); // 每行保证有M个字符 if(line.length() != M) throw new IllegalArgumentException("Maze file " + filename + " is invalid"); for (int j = 0; j < M; j ++) { maze[i][j] = line.charAt(j); visited[i][j] = false; path[i][j] = false; } } } catch (IOException e){ e.printStackTrace(); } finally { if (scanner != null) scanner.close(); } // 入口，第二行第一列 entranceX = 1; entranceY = 0; // 出口，倒数第二行最后一列 exitX = N - 2; exitY = M - 1; } public int N(){ return N; } public int M(){ return M; } public int getEntranceX(){return entranceX;} public int getEntranceY(){return entranceY;} public int getExitX(){return exitX;} public int getExitY(){return exitY;} public char getMaze(int i, int j){ if (!inArea(i, j)) throw new IllegalArgumentException("i or j is out of index in getMaze!"); return maze[i][j]; } // 判断点(x,y)是否在迷宫中 public boolean inArea(int x, int y){ return x >= 0 && x < N && y >= 0 && y < M; } // 控制台打印迷宫 public void print(){ System.out.println(N + " " + M); for(int i = 0 ; i < N ; i ++){ for(int j = 0 ; j < M ; j ++) System.out.print(maze[i][j]); System.out.println(); } return; } }
将迷宫的各个位置封装成一个类 Position.java，便于操作
public class Position { private int x, y; public Position(int x, int y, Position prev){ this.x = x; this.y = y; } public Position(int x, int y){ this(x, y, null); } public int getX(){ return x; } public int getY(){ return y; } public void setX(int x){ this.x = x; } public void setY(int y){ this.y = y; } }
视图层
AlgoFrame.java 是绘制界面的核心代码，使用java的JFrame控件，在上面添加JPanel画板，在JFrame中定义渲染方法render来调用画板的 paintComponent 方法实现绘制，其中需要用到自己定义的绘制辅助类 AlgoVisHelper.java，在里面封装了绘制矩形，设置画笔颜色，停顿等方法，也定义了一些颜色，也可以不用定义该辅助类而直接在 AlgoFrame.java 中使用awt包中的各种方法直接实现，如有需要可自行下载代码。
import java.awt.*; import javax.swing.*; public class AlgoFrame extends JFrame{ private int canvasWidth; private int canvasHeight; public AlgoFrame(String title, int canvasWidth, int canvasHeight){ super(title); this.canvasWidth = canvasWidth; this.canvasHeight = canvasHeight; AlgoCanvas canvas = new AlgoCanvas(); setContentPane(canvas); pack(); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setResizable(false); setVisible(true); } public AlgoFrame(String title){ this(title, 1024, 768); } public int getCanvasWidth(){return canvasWidth;} public int getCanvasHeight(){return canvasHeight;} private MazeData data; public void render(MazeData data){ this.data = data; repaint(); } private class AlgoCanvas extends JPanel{ public AlgoCanvas(){ // 双缓存 super(true); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2d = (Graphics2D)g; // 抗锯齿 RenderingHints hints = new RenderingHints( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); hints.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); g2d.addRenderingHints(hints); // 具体绘制 int w = canvasWidth / data.M(); // 宽 int h = canvasHeight / data.N();// 高 for (int i = 0; i < data.N(); i ++){ for (int j = 0; j < data.M(); j ++){ if (data.getMaze(i,j) == MazeData.WALL) AlgoVisHelper.setColor(g2d, AlgoVisHelper.LightBlue); else AlgoVisHelper.setColor(g2d, AlgoVisHelper.White); if (data.path[i][j] && data.showPath == true) AlgoVisHelper.setColor(g2d, AlgoVisHelper.Yellow); if (data.player.getX() == i && data.player.getY() == j) AlgoVisHelper.setColor(g2d, AlgoVisHelper.Red); AlgoVisHelper.fillRectangle(g2d, j*w, i*h, w, h); } } } @Override public Dimension getPreferredSize(){ return new Dimension(canvasWidth, canvasHeight); } } }
控制层
主函数 AlgoVisualizer.java ，其中在程序运行最开始时采用了基于递归的DFS算法将迷宫的解事先求出，用户按下空格则可以实现提示功能，红色表示玩家，键盘上下左右控制四个方向的移动。run()方法实现了所有的动画逻辑
import java.awt.*; import java.awt.event.KeyAdapter; import java.awt.event.KeyEvent; public class AlgoVisualizer { private static int DELAY = 10; private static int blockSide = 8; private MazeData data; private AlgoFrame frame; private static final int d[][] = {{-1,0},{0,1},{1,0},{0,-1}}; // 四个方向移动 public AlgoVisualizer(String mazeFile){ // 初始化数据 data = new MazeData(mazeFile); int sceneHeight = data.N() * blockSide; int sceneWidth = data.M() * blockSide; // 初始化视图 EventQueue.invokeLater(() -> { frame = new AlgoFrame("Maze Solver Visualization", sceneWidth, sceneHeight); frame.addKeyListener(new AlgoKeyListener()); new Thread(() -> { run(); }).start(); }); } public void run(){ setData(-1, -1, false); data.player = new Position(data.getEntranceX(), data.getEntranceY()); // 递归实现 if(!autoGo(data.getEntranceX(), data.getEntranceY())) System.out.println("The maze has NO solution!"); System.out.println("初始化已完成"); while (true){ frame.render(data); AlgoVisHelper.pause(DELAY); setData(-1, -1, false); if (data.player.getX() == data.getExitX() && data.player.getY() == data.getExitY()){ System.out.println("游戏结束"); frame.render(data); AlgoVisHelper.pause(DELAY); break; } } setData(-1, -1, false); } // 返回值：求解是否成功 private boolean autoGo(int x, int y){ if(!data.inArea(x,y)) throw new IllegalArgumentException("x,y are out of index in go function!"); data.visited[x][y] = true; setData(x, y, true); if (x == data.getExitX() && y == data.getExitY()) return true; for (int i = 0; i < 4; i ++){ int newX = x + d[i][0]; int newY = y + d[i][1]; if (data.inArea(newX, newY) && data.getMaze(newX, newY) == MazeData.ROAD && !data.visited[newX][newY]){ if (autoGo(newX, newY)) return true; } } setData(x, y, false); return false; } private void setData(int x, int y, boolean isPath){ if (data.inArea(x, y)) data.path[x][y] = isPath; } private class AlgoKeyListener extends KeyAdapter{ @Override public void keyPressed(KeyEvent event){ if (event.getKeyCode() == KeyEvent.VK_LEFT){ System.out.println("go left"); oneStep(data.player.getX(), data.player.getY(), 3); } else if (event.getKeyCode() == KeyEvent.VK_DOWN){ System.out.println("go down"); oneStep(data.player.getX(), data.player.getY(), 2); } else if (event.getKeyCode() == KeyEvent.VK_RIGHT){ System.out.println("go right"); oneStep(data.player.getX(), data.player.getY(), 1); } else if (event.getKeyCode() == KeyEvent.VK_UP){ System.out.println("go up"); oneStep(data.player.getX(), data.player.getY(), 0); } else if (event.getKeyChar() == ' '){ System.out.println("显示提示"); data.showPath = !data.showPath; } } } private void oneStep(int x, int y, int direction){ int newX = x + d[direction][0]; int newY = y + d[direction][1]; if (data.inArea(newX, newY) && data.getMaze(newX, newY) == MazeData.ROAD){ data.player.setX(newX); data.player.setY(newY); } } public static void main(String[] args) { String mazefile = "maze_101_101.txt"; AlgoVisualizer vis = new AlgoVisualizer(mazefile); } }
