XML解析以及增删改查的操作2

import java.io.Serializable;
import java.util.List;
/**
 * xml文档节点基类，可以是普通节点，注释节点,文本节点
 * */
public abstract class Node implements Serializable,INodeAction{

 /**
 * 序列化版本号
 */
 private static final long serialVersionUID = 3858789701720999153L;
 /**
 * 父节点.规定 根节点的父节点为空
 * */
 protected Element father;
 /**
 * 由文档对象直接添加的节点 domFather赋值为document对象
 * */
 protected Document domFather;
 @Override
 public Integer getBeifen(){
 Integer n;
 if(father==null){
  n = 0;
  return n;
 }
 Node node = this;
 n = 0;
 while(node.father!=null){
  n++;
  node = node.father;
  if(node.father==null){
  return n;
  }
 }
 if(!(node.father==null)){
  return null;
 }
 return n;
 }
 
 public Element getFather() {
 return father;
 }
 @Override
 public String printSpace() {
 StringBuffer sb = new StringBuffer();
 Integer n = getBeifen();
 if (n == null) {
  return sb.toString();
 }
 for (int i = 0; i < n; i++) {
  sb.append(" ");
 }
 return sb.toString();
 }
 
 public Document getDomFather() {
 return domFather;
 }
 
 @Override
 public Node getPreviousSibling(){
 if(father==null){
  if(domFather==null){
  DocumentUtil.throwException("节点还没添加到文档！");
  }else{
  List nodeList = domFather.getNodeList();
  int idx = nodeList.indexOf(this);
  return idx==0?null:nodeList.get(idx-1);
  }
 }
 List nodeList = father.getNodeList();
 int idx = nodeList.indexOf(this);
 return idx==0?null:nodeList.get(idx-1);
 }
 
 @Override
 public Node getNextSibling() {
 if(father==null){
  if(domFather==null){
  DocumentUtil.throwException("节点还没添加到文档！");
  }else{
  List nodeList = domFather.getNodeList();
  int idx = nodeList.indexOf(this);
  return idx==nodeList.size()-1?null:nodeList.get(idx+1);
  }
 }
 List nodeList = father.getNodeList();
 int idx = nodeList.indexOf(this);
 return idx==nodeList.size()-1?null:nodeList.get(idx+1);
 }
}