构建二叉树

createBinTree.java

public static <R> R buildTreeByStrings2(Integer[] input, Class<R> clazz) {//R为结点类型
    if (input == null || input.length == 0) return null;
    Method getLeft = null;
    Method getRight = null;
    Method setLeft = null;
    Method setRight = null;
    try {//一定得有这几个方法
        getLeft = clazz.getMethod("getLeft");
        getRight = clazz.getMethod("getRight");
        setLeft = clazz.getMethod("setLeft",clazz);
        setRight = clazz.getMethod("setRight",clazz);
    } catch (Exception e) {
        System.out.println("没有该方法");
    }

    R root = createNode(clazz, input[0]);
    try {
        if (root != null) {
            Queue<R> queue = new LinkedList<>();
            queue.offer(root);
            int i = 1;
            while (i < input.length) {
                R node = queue.poll();
                R leftChild = createNode(clazz, input[i++]);
                setLeft.invoke(node, leftChild);
                if (i < input.length)
                    setRight.invoke(node, createNode(clazz, input[i++]));
                if (getLeft.invoke(node) != null) queue.offer((R) getLeft.invoke(node));
                if (getRight.invoke(node) != null) queue.offer((R) getRight.invoke(node));
            }
        }
    } catch (Exception ignored) {
    }

    return root;
}

private static <R> R createNode(Class<R> clazz, Integer val) {
    R node = null;
    try {
        Constructor<R> constructor = clazz.getConstructor(int.class);
        node = constructor.newInstance(val);
    } catch (Exception ignored) {
    }
    return node;
}