1、二叉树节点类

public class TreeNode {    int val = 0;    TreeNode left = null;    TreeNode right = null;    public TreeNode(int val) {        this.val = val;    }    public TreeNode(int val, TreeNode left, TreeNode right) {        this.val = val;        this.left = left;        this.right = right;    }    //----------------------------    public int getVal() {        return val;    }    public void setVal(int val) {        this.val = val;    }    public TreeNode getLeft() {        return left;    }    public void setLeft(TreeNode left) {        this.left = left;    }    public TreeNode getRight() {        return right;    }    public void setRight(TreeNode right) {        this.right = right;    }}

2、二叉树打印类

public class PrintTree {    public void printNode(TreeNode node){        System.out.print(node.getVal());    }    //先序遍历    public void theFirstTraversal(TreeNode root) {        printNode(root);        if (root.getLeft() != null) {  //使用递归进行遍历左孩子              theFirstTraversal(root.getLeft());        }        if (root.getRight() != null) {  //递归遍历右孩子              theFirstTraversal(root.getRight());        }    }    //中序遍历    public void theInOrderTraversal(TreeNode root) {        if (root.getLeft() != null) {            theInOrderTraversal(root.getLeft());        }        printNode(root);        if (root.getRight() != null) {            theInOrderTraversal(root.getRight());        }    }    //后序遍历    public void thePostOrderTraversal(TreeNode root) {        if (root.getLeft() != null) {            thePostOrderTraversal(root.getLeft());        }        if(root.getRight() != null) {            thePostOrderTraversal(root.getRight());        }        printNode(root);    }}

3、判断二叉树是否包含另一棵树的类

public class HasSubtree {    public boolean hasSubtree(TreeNode root1, TreeNode root2) {        boolean result = false;        //当Tree1和Tree2都不为零的时候，才进行比较。否则直接返回false        if (root2 != null && root1 != null) {            //如果找到了对应Tree2的根节点的点            if (root1.val == root2.val) {                //以这个根节点为为起点判断是否包含Tree2                result = doesTree1HaveTree2(root1, root2);            }            //如果找不到，那么就再去root的左叶子当作起点，去判断时候包含Tree2            if (!result) {                result = hasSubtree(root1.left, root2);            }            //如果还找不到，那么就再去root的右儿子当作起点，去判断时候包含Tree2            if (!result) {                result = hasSubtree(root1.right, root2);            }        }        //返回结果        return result;    }    public static boolean doesTree1HaveTree2(TreeNode node1, TreeNode node2) {        //如果Tree2已经遍历完了都能对应的上，返回true        if (node2 == null) {            return true;        }        //如果Tree2还没有遍历完，Tree1却遍历完了。返回false        if (node1 == null) {            return false;        }        //如果其中有一个点没有对应上，返回false        if (node1.val != node2.val) {            return false;        }        //如果根节点对应的上，那么就分别去子节点里面匹配        return doesTree1HaveTree2(node1.left, node2.left) && doesTree1HaveTree2(node1.right, node2.right);    }}

4、测试类

public class TestMain {    public static void main(String[] args) {        //创建二叉树tree1        TreeNode root1=new TreeNode(0);        TreeNode node11=new TreeNode(1);        TreeNode node12=new TreeNode(2);        TreeNode node13=new TreeNode(3);        TreeNode node14=new TreeNode(4);        TreeNode node15=new TreeNode(5);        TreeNode node16=new TreeNode(6);        root1.setLeft(node11);        root1.setRight(node12);        node11.setLeft(node13);        node11.setRight(node14);        node12.setLeft(node15);        node12.setRight(node16);        //采用前序遍历方式打印二叉树        PrintTree p=new PrintTree();        p.theFirstTraversal(root1);        System.out.println();        //创建二叉树tree2        TreeNode root2=new TreeNode(1);        TreeNode node21=new TreeNode(3);        TreeNode node22=new TreeNode(4);        root2.setLeft(node21);        root2.setRight(node22);        //采用前序遍历方式打印二叉树        PrintTree p2=new PrintTree();        p2.theFirstTraversal(root2);        System.out.println();        //判断tree2是否为tree1的子树        HasSubtree h=new HasSubtree();        Boolean b=h.hasSubtree(root1,root2);        System.out.println("是否包含："+b);    }}