A*—java代码

import java.util.ArrayList;

// A*算法寻路
public class AStar2 {
    public static final int[][] maps = {
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 1, 0, 0, 0, 0, 0},
            {0, 0, 0, 0, 0, 0, 0, 0, 0},
    };

    public static int straight = 10;
    public static int diagonal = 14;

    // 开放列表
    public static ArrayList<Node> openList = new ArrayList<>();
    // 闭合列表
    public static ArrayList<Node> colseList = new ArrayList<>();
    // 方向
    public static int[][] direct = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}, {1, 1}, {1, -1}, {-1, 1}, {-1, -1}};

    public static void main(String[] args) {
        //定点:起点终点
        Node start = new Node(5, 1);
        Node end = new Node(5, 4);

        Node endNode = findPath(start, end);

        printMap(maps, start, end);

        ArrayList<Node> arrayList = endNode != null ? getPaths(endNode) : null;

        printPaths(arrayList);

    }

    // 从起点开始，找到到终点的一条最短路径
    private static Node findPath(Node start, Node end) {
        start.G = 0;
        openList.add(start);

        while (!openList.isEmpty()) {
            //从开放列表中拿到最小F节点
            Node cureNode = minFINOpenList(openList);
            openList.remove(cureNode);
            // 将该节点加入到闭合列表中
            colseList.add(cureNode);

            // 当前节点的全部合法邻居
            ArrayList<Node> neighbors = getNeighbor(cureNode);
            for (Node nbrNode : neighbors) {
                // 邻居已经在openList
                if (exists(openList, nbrNode) != null)
                    updateG(cureNode, nbrNode);
                    // 邻居不在openList
                else joinOpenList(cureNode, nbrNode, end);
            }
            if (exists(openList, end) != null)
                return exists(openList, end);
        }

        return null;
    }

    private static ArrayList<Node> getPaths(Node endNode) {
        ArrayList<Node> arrayList = new ArrayList<>();
        Node parent = endNode;
        while (parent != null) {
            arrayList.add(parent);
            parent = parent.parent;
        }
        return arrayList;
    }

    private static int calStep(Node node, Node cur) {
        if (inLine(node, cur))
            return straight;
        else return diagonal;
    }

    private static int calH(Node endNode, Node nbrNode) {
        return Math.abs(endNode.y - nbrNode.y) + Math.abs(endNode.x - nbrNode.x);
    }

    // 计算距离起点的距离
    private static int calG(Node cureNode, Node nbrNode) {
        int step = calStep(cureNode, nbrNode);
        return cureNode.G + step;
    }

    private static boolean inLine(Node nbr, Node cur) {
        if (nbr.x == cur.x || nbr.y == cur.y)
            return true;
        return false;
    }

    // 途径当前节点到达节点node的路径G会不会更短
    private static void updateG(Node cureNode, Node nbrNode) {
        int step = calStep(cureNode, nbrNode);
        int G = calG(cureNode, nbrNode);
        if (G < nbrNode.G) {
            nbrNode.G = G;
            nbrNode.parent = cureNode;
            nbrNode.calcF();
        }
    }

    private static void joinOpenList(Node curNode, Node nbrNode, Node endNode) {
        openList.add(nbrNode);
        nbrNode.parent = curNode;
        nbrNode.G = calG(curNode, nbrNode);
        nbrNode.H = calH(endNode, nbrNode);
        nbrNode.calcF();
    }

    // 达到当前节点的可达，且不在closeList中的邻居节点
    private static ArrayList<Node> getNeighbor(Node cureNode) {
        ArrayList<Node> arrayList = new ArrayList<>();
        //从当前节点想八个方向扩散
        for (int i = 0; i < 8; i++) {
            int newRow = cureNode.x + direct[i][0];
            int newCol = cureNode.y + direct[i][1];
            //当前邻居节点: 可达、不在closeList中
            if (isAccesse(newRow, newCol) && !exists(colseList, newRow, newCol)) {
                arrayList.add(new Node(newRow, newCol));
            }
        }
        return arrayList;
    }

    private static Node exists(ArrayList<Node> colseList, Node cur) {
        for (Node node : colseList) {
            if (node.x == cur.x && node.y == cur.y)
                return node;
        }
        return null;
    }

    private static boolean exists(ArrayList<Node> colseList, int newX, int newY) {
        for (Node node : colseList) {
            if (node.x == newX && node.y == newY)
                return true;
        }
        return false;
    }

    // 可达性分析(非障碍物)
    private static boolean isAccesse(int newX, int newY) {
        if (0 <= newX && newX < maps.length && 0 <= newY && newY < maps[0].length)
            return maps[newX][newY] == 0;
        return false;
    }

    // 从开放列表中找到最小F=G+H的节点
    private static Node minFINOpenList(ArrayList<Node> openList) {
        Node min = openList.get(0);
        for (Node node : openList) {
            if (node.F < min.F)
                min = node;
        }
        return min;
    }

    private static void printMap(int[][] maps, Node start, Node end) {

        for (int col = 0; col < maps[0].length; col++) {
            System.out.print("	" + col + "");
        }
        System.out.print("
-----------------------------------------
");
        int count = 0;
        for (int row = 0; row < maps.length; row++) {
            for (int col = 0; col < maps[0].length; col++) {
                if (col == 0)
                    System.out.print(count++ + "|	");
                if (row == start.x && col == start.y || row == end.x && col == end.y)
                    System.out.print("X	");
                else
                    System.out.print(maps[row][col] + "	");
            }
            System.out.println();
        }
        System.out.println();
    }

    public static void printPaths(ArrayList<Node> arrayList) {
        if (arrayList == null) {
            System.out.println("无路可走");
            return;
        }

        // 地图形式
        for (int col = 0; col < maps[0].length; col++) {
            System.out.print("	" + col + "");
        }
        System.out.print("
-----------------------------------------
");
        int count = 0;

        for (int row = 0; row < maps.length; row++) {
            for (int col = 0; col < maps[0].length; col++) {
                if (col == 0)
                    System.out.print(count++ + "|	");
                if (exists(arrayList, row, col)) {
                    System.out.print("X	");
                } else {
                    System.out.print(maps[row][col] + "	");
                }

            }
            System.out.println();
        }
        System.out.println();
        // 路径形式
        for (int i = arrayList.size() - 1; i >= 0; i--) {
            if (i == 0)
                System.out.print(arrayList.get(i));
            else
                System.out.print(arrayList.get(i) + "->");
        }
        System.out.println();
    }


}

结果

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    0    0    0    0    0    0    
1|    0    0    0    0    0    0    0    0    0    
2|    0    0    0    0    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    0    0    1    0    0    0    0    0    
7|    0    0    0    1    0    0    0    0    0    
8|    0    0    0    1    0    0    0    0    0    

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    0    0    0    0    0    0    
1|    0    0    0    0    0    0    0    0    0    
2|    0    0    0    X    0    0    0    0    0    
3|    0    0    X    1    X    0    0    0    0    
4|    0    X    0    1    X    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    0    0    1    0    0    0    0    0    
7|    0    0    0    1    0    0    0    0    0    
8|    0    0    0    1    0    0    0    0    0    

(5,1)->(4,1)->(3,2)->(2,3)->(3,4)->(4,4)->(5,4)

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    0    0    0    0    0    0    
1|    0    0    0    0    0    0    0    0    0    
2|    0    0    0    0    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    0    X    0    0    0    0    
6|    0    0    0    0    0    0    0    0    0    
7|    0    0    0    1    0    0    0    0    0    
8|    0    0    0    0    0    0    0    0    0    

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    0    0    0    0    0    0    
1|    0    0    0    0    0    0    0    0    0    
2|    0    0    0    0    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    X    X    X    0    0    0    0    
6|    0    0    0    0    0    0    0    0    0    
7|    0    0    0    1    0    0    0    0    0    
8|    0    0    0    0    0    0    0    0    0    

(5,1)->(5,2)->(5,3)->(5,4)

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    0    0    0    0    0    0    
1|    0    0    0    0    0    0    0    0    0    
2|    0    0    0    0    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    0    0    1    0    0    0    0    0    
7|    0    0    0    0    0    0    0    0    0    
8|    0    0    0    0    0    0    0    0    0    

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    0    0    0    0    0    0    
1|    0    0    0    0    0    0    0    0    0    
2|    0    0    0    0    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    0    X    1    X    0    0    0    0    
7|    0    0    0    X    0    0    0    0    0    
8|    0    0    0    0    0    0    0    0    0    

(5,1)->(6,2)->(7,3)->(6,4)->(5,4)

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    1    0    0    0    0    0    
1|    0    0    0    1    0    0    0    0    0    
2|    0    0    0    1    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    0    0    1    0    0    0    0    0    
7|    0    0    0    1    0    0    0    0    0    
8|    0    0    0    1    0    0    0    0    0    

无路可走

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    1    0    0    0    0    0    
1|    0    0    0    1    0    0    0    0    0    
2|    0    0    0    1    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    0    0    1    0    0    0    0    0    
7|    0    0    0    1    0    0    0    0    0    
8|    0    0    0    0    0    0    0    0    0    

    0    1    2    3    4    5    6    7    8
-----------------------------------------
0|    0    0    0    1    0    0    0    0    0    
1|    0    0    0    1    0    0    0    0    0    
2|    0    0    0    1    0    0    0    0    0    
3|    0    0    0    1    0    0    0    0    0    
4|    0    0    0    1    0    0    0    0    0    
5|    0    X    0    1    X    0    0    0    0    
6|    0    X    0    1    X    0    0    0    0    
7|    0    0    X    1    X    0    0    0    0    
8|    0    0    0    X    0    0    0    0    0    

(5,1)->(6,1)->(7,2)->(8,3)->(7,4)->(6,4)->(5,4)