请用java写二叉树算法，兑现添加数据形式二叉树功能，并以先序的方式打印出来

请用java写二叉树算法，实现添加数据形式二叉树功能，并以先序的方式打印出来
import java.io.*;
import java.util.Stack;

public class MyTest {
private MyTree tree;

/**
* 二叉树的插入，参数为（关键字，数据）
*
*/
public void insert(int key, int data) {
if (tree == null) {
tree = new MyTree();
tree.key = key;
tree.data = data;
} else {
MyTree newTree = new MyTree();
newTree.key = key;
newTree.data = data;
MyTree parent = tree;
while (true) {
if (newTree.key < parent.key) {
if (parent.leftChild == null) {
parent.leftChild = newTree;
return;
} else {
parent = parent.leftChild;
}
} else if (newTree.key > parent.key) {
if (parent.rightChild == null) {
parent.rightChild = newTree;
return;
} else {
parent = parent.rightChild;
}
}
}

}
}

/***************************************************************************
* 二叉树的查找，参数为（关键字），返回值为 myTree的一个实例
*
**************************************************************************/
public MyTree find(int key) {
if (tree == null)
return null;
MyTree curr = new MyTree();
curr.key = key;
MyTree parent = tree;
while (true) {
if (parent == null) {
return null;
} else if (curr.key == parent.key) {
return parent;
} else if (curr.key > parent.key) {
parent = parent.rightChild;
} else if (curr.key < parent.key) {
parent = parent.leftChild;
}
}
}

/*
*
* 递归的二叉树中序遍历
*
*
*/
private static void midOrder(MyTree tree) {
if (tree != null) {
midOrder(tree.leftChild);
System.out.println(tree + "," + tree.key + "," + tree.data);
midOrder(tree.rightChild);
}
}

/*
* 前序遍历
*/
private static void frontOrder(MyTree tree) {
if (tree != null) {
System.out.println("" + tree.key + "   ,   " + tree.data);
frontOrder(tree.leftChild);
frontOrder(tree.rightChild);
}
}

class MyTree {
int key;

int data;

MyTree leftChild;

MyTree parentChild;

MyTree rightChild;

public String toString() {
return "haha";
}
}

public static void main(String[] args) {
System.out.println("Tree   view   Begin");
MyTest t1 = new MyTest();
t1.insert(8, 25);
t1.insert(5, 9);
t1.insert(58, 87);
t1.insert(13, 82);
t1.insert(4,;
t1.insert(12, 54);
t1.insert(53, 123);
t1.insert(56, 47);
t1.insert(2, 75);
t1.insert(34, 5);
t1.insert(6, 23);
System.out.println("现在开始遍历:");
// midOrder2(t1.tree);
midOrder(t1.tree);
}
}