求一个二叉树的深度以及如何判断一个二叉树是一个平衡二叉树

/**
 * Created by Administrator on 2015/10/10.
 */
public class TreeNode {
    //树节点的值
    private char data;
    //节点的左子树
    private TreeNode leftTree;
    //节点的右子树
    private TreeNode rightTree;
    public TreeNode(char data,TreeNode leftTree,TreeNode rightTree){
        this.data=data;
        this.leftTree=leftTree;
        this.rightTree=rightTree;
    }
    public int getData() {
        return data;
    }
    public void setData(char data) {
        this.data = data;
    }
    public TreeNode getLeftTree() {
        return leftTree;
    }
    public void setLeftTree(TreeNode leftTree) {
        this.leftTree = leftTree;
    }
    public TreeNode getRightTree() {
        return rightTree;
    }
    public void setRightTree(TreeNode rightTree) {
        this.rightTree = rightTree;
    }
    public static int getDepth(TreeNode pNode){
        if(pNode==null){
            return -1;
        }
        TreeNode leftTree=pNode.getLeftTree();
        TreeNode rightTree=pNode.getRightTree();
        if(leftTree==null||rightTree==null){
            return 0;
        }
        int leftDepth=getDepth(leftTree);
        int rightDepth=getDepth(rightTree);
        int depth=leftDepth>rightDepth?leftDepth:rightDepth;
        return depth+1;
    }
    //判断二叉树是否为一个平衡二叉树
    public static boolean isBalance(TreeNode pNode){
        if (pNode==null){
            return true;
        }
        TreeNode leftTree=pNode.getLeftTree();
        TreeNode rightTree=pNode.getRightTree();
        int leftDepth=getDepth(leftTree);
        int rightDepth=getDepth(rightTree);
        if(leftDepth-rightDepth>1||rightDepth-leftDepth>1){
            return false;
        }
        if(isBalance(leftTree)){
            return isBalance(rightTree);
        }else{
            return false;
        }
    }
    //测试
    public static void main(String[] args){
        //TreeNode D=new TreeNode('D',null,null);
        TreeNode E=new TreeNode('E',null,null);
        TreeNode F=new TreeNode('F',null,null);
        TreeNode C=new TreeNode('C',E,F);
        //TreeNode B=new TreeNode('B',D,null);
        TreeNode A=new TreeNode('A',null,C);
        System.out.println(isBalance(A));
        //System.out.println(getDepth(A));
    }
}