java操作xml的一個(gè)小例子
最近一直在做高效平臺(tái)的框架，其實(shí)意識(shí)到我要做一個(gè)簡(jiǎn)單的框架的時(shí)候是在我已經(jīng)做完我認(rèn)為的一版界面之后，開始以為我要做的是一個(gè)可配置的首頁(yè)展示，但是吭哧吭哧做了兩個(gè)星期，大概功能實(shí)現(xiàn)了之后，才發(fā)現(xiàn)要做的不是這個(gè)，哎，需求不清楚害死人啊，但是這兩個(gè)星期并沒有白白浪費(fèi)，也從中學(xué)到了很多東西，下面主要介紹讀取XML。
在做系統(tǒng)的時(shí)候，經(jīng)常會(huì)遇到讀取xml的需求，一開始是讀取，于是我上網(wǎng)開始查詢讀取，接著查詢刪除，接著查詢修改，當(dāng)把這些代碼查的差不多的時(shí)候，我發(fā)現(xiàn)，我為什么不把這些的`操作都封裝到一個(gè)類里，使用的時(shí)候直接調(diào)用，豈不是更好，感覺之前腦袋都秀逗了，分別查了那么多，還一個(gè)個(gè)的調(diào)試，抱著這個(gè)心態(tài)繼續(xù)上網(wǎng)查（因?yàn)槲艺嫘母杏X網(wǎng)上肯定有，如果我自己封裝的話腦袋就真的進(jìn)水了）。
源代碼展示：
復(fù)制代碼 代碼如下:
package com.gxpt.struts2;
import java.io.File;
import java.io.FileWriter;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
public class testAddDeleteXML {
private Document document;
private String filePath; //文件所在的實(shí)際物理路徑
//private WriteLog writelog;
public static void main(String[] args) throws DocumentException {
//String filepath = System.getProperty("user.dir")+"/XmlFiles/LocalServicesConfig.xml";
String filepath ="F:JAVA項(xiàng)目高校平臺(tái)demogxptWebContentlimitsmanager.txt";
testAddDeleteXML operator = new testAddDeleteXML(filepath);
operator.getXmlFile();
//Map map = new HashMap();
//map.put("id", "m1");
//map.put("name","module1");
//map.put("url", "index1.jsp");
//operator.addChild("div", "div9","module", "",map);
//operator.updateChild("style", "", "div", "asdfasdf",1);
operator.ChildOne("style", "","div","div11");
//operator.Child("div", "div9","module");
//String str = operator.getChild("div", "div8", "module");
//System.out.println(str);
//Element root = document.getRootElement();//獲取根節(jié)點(diǎn)名稱
}
public testAddDeleteXML(String filepath){
this.document = null;
this.filePath = filepath;
//writelog = new WriteLog();
}
/**
* 創(chuàng)建XML文件
* @param rootName:根節(jié)點(diǎn)名稱
*/
public void createXMLFile(String rootName) {
if(!fileExist()){
this.document = DocumentHelper.createDocument();
this.document.addElement(rootName);
saveXMLFile(this.document);
}
}
/**
* 獲取已存在的XML文檔
* @return
*/
public Document getXmlFile() {
if (fileExist()) {
SAXReader reader = new SAXReader();
try {
this.document = reader.read(new File(filePath));
} catch (DocumentException e) {
// String loginfo = StackTraceToString.getExceptionTrace(e);
// writelog.writeLogToEnd("LocalServerManager", loginfo);
}finally{
reader = null;
}
} else {
//寫日志
// String loginfo = "XML file does not exist,read error!";
// writelog.writeLogToEnd("LocalServerManager",loginfo);
System.exit(0);
}
return this.document;
}
/**
* 添加元素
* @param fatherPath:父節(jié)點(diǎn)名稱
* @param fatherattr:父節(jié)點(diǎn)屬性
* @param childName：要添加的節(jié)點(diǎn)名稱
* @param childValue：要添加的節(jié)點(diǎn)值
*/
public void addChild(String fatherNode, String fatherAttr,String childName, String childValue,Map mapAttr) {
ChildOperator(fatherNode,fatherAttr,childName,childValue,"add",mapAttr,0);
}
/**
* 修改元素
* @param fatherPath:父節(jié)點(diǎn)名稱
* @param fatherattr:父節(jié)點(diǎn)屬性
* @param childName：要修改的節(jié)點(diǎn)名稱
* @param childValue：要修改成的節(jié)點(diǎn)值
*/
public void updateChild(String fatherNode, String fatherAttr,String childName, String childValue,int updatId) {
ChildOperator(fatherNode,fatherAttr,childName,childValue,"update",null,updatId);
}
/**
* 刪除元素
* @param fatherPath:父節(jié)點(diǎn)名稱
* @param fatherattr:父節(jié)點(diǎn)屬性
* @param childName：要?jiǎng)h除的節(jié)點(diǎn)名稱
*/
public void Child(String fatherNode, String fatherAttr,String childName) {
ChildOperator(fatherNode,fatherAttr,childName,"","",null,0);
}
/**
* 刪除元素
* @param fatherPath:父節(jié)點(diǎn)名稱
* @param fatherattr:父節(jié)點(diǎn)屬性
* @param childName：要?jiǎng)h除的節(jié)點(diǎn)名稱
*/
public void ChildAll(String fatherNode, String fatherAttr,String childName) {
ChildOperator(fatherNode,fatherAttr,childName,"","All",null,0);
}
/**
* 刪除某個(gè)元素
* @param fatherPath:父節(jié)點(diǎn)名稱
* @param fatherattr:父節(jié)點(diǎn)屬性
* @param childName：要?jiǎng)h除的節(jié)點(diǎn)名稱
*/
public void ChildOne(String fatherNode, String fatherAttr,String childName,String childValue) {
ChildOperator(fatherNode,fatherAttr,childName,childValue,"One",null,0);
}
/**
* 獲取某個(gè)元素?cái)?shù)值
* @param fatherPath:父節(jié)點(diǎn)名稱
* @param fatherattr:父節(jié)點(diǎn)屬性
* @param childName：要?jiǎng)h除的節(jié)點(diǎn)名稱
*/
public String getChild(String fatherNode, String fatherAttr,String childName) {
String result = "";
result = ChildOperator(fatherNode,fatherAttr,childName,"","get",null,0);
return result;
}
/**
* 子節(jié)點(diǎn)操作
* @param fatherNode:父節(jié)點(diǎn)名稱
* @param fatherAttr:父節(jié)點(diǎn)屬性
* @param childName：要修改的節(jié)點(diǎn)
* @param childValue：修改后的節(jié)點(diǎn)值
* @param operator: 要執(zhí)行的操作名稱
*/
private synchronized String ChildOperator(String fatherNode, String fatherAttr,String childName, String childValue,String operator,Map mapAttr,int updateId) {
String result="";
if (this.document == null) {
return "null";
}
Element root = this.document.getRootElement();//獲取根節(jié)點(diǎn)名稱
if(!root.getName().equals(fatherNode)){ //如果不是在根節(jié)點(diǎn)下添加
result = XmlElementOperator(root,fatherNode,fatherAttr,childName,childValue,operator,mapAttr);
}else{
if(operator.equals("add")){
Element childelement = root.addElement(childName);//根節(jié)點(diǎn)不存在元素屬性值
childelement.setAttributeValue("id",childValue);
saveXMLFile(this.document);
}else if(operator.equals("update")){
List childelements = root.elements(childName);
// for(Iterator childs=childelements.iterator();childs.hasNext();){
// Element everyone = (Element)childs.next();
// everyone.setText(childValue); //修改該元素值
// everyone.setAttributeValue("id",childValue);
Element everyone = (Element)childelements.get(updateId);
everyone.setAttributeValue("id",childValue);
// }
saveXMLFile(this.document);
}else if(operator.equals("")){
List childelements = root.elements(childName);//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
List childelements1 = everyone.elements("module");
for(Iterator childs1=childelements1.iterator();childs1.hasNext();){
Element everyone1 = (Element)childs1.next();
everyone.remove(everyone1);
}
}
saveXMLFile(this.document);
}else if(operator.equals("get")){
List childelements = root.elements(childName);//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
result = everyone.getText();
}
saveXMLFile(this.document);
}else if(operator.equals("One")){
List childelements = root.elements(childName);//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
String divElement = everyone.attributeValue("id");
if(divElement.equals(childValue)){
root.remove(everyone);
}
}
saveXMLFile(this.document);
}else if(operator.equals("All")){
List childelements = root.elements();//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
List childeDiv = everyone.elements();
for(Iterator childsDiv=childeDiv.iterator();childsDiv.hasNext();){
Element everyoneDiv = (Element)childsDiv.next();
everyone.remove(everyoneDiv);
}
}
}
saveXMLFile(this.document);
}
return result;
}
/**
* 遞歸元素操作
* @param element:要遞歸的元素
* @param fatherNode:父節(jié)點(diǎn)名稱
* @param fatherAttr:父節(jié)點(diǎn)屬性
* @param childName：要進(jìn)行操作的節(jié)點(diǎn)
* @param childValue：操作后的節(jié)點(diǎn)值
* @param operator: 要執(zhí)行的操作名稱
*/
private synchronized String XmlElementOperator(Element element,String fatherNode,String fatherAttr,String childName,String childValue,String operator,Map mapAttr){
String result = "";
List elements = element.elements();
for(Iterator it=elements.iterator();it.hasNext();){
Element currentelement = (Element)it.next();
if(!currentelement.getName().equals(fatherNode)){ //當(dāng)前元素并不是我們要查找的父元素時(shí)，繼續(xù)查找
XmlElementOperator(currentelement,fatherNode,fatherAttr,childName,childValue,operator,mapAttr);//遞歸調(diào)用
}else{
if(currentelement.attributeCount()>0){ //當(dāng)前元素存在屬性值時(shí)
for(Iterator list=currentelement.attributeIterator();list.hasNext();){ //遍歷屬性值
Attribute attr = (Attribute)list.next(); //獲取屬性值隊(duì)列中的第一個(gè)元素
if(attr.getValue().equals(fatherAttr)){//根據(jù)屬性值確定惟一的父元素
if(operator.equals("add")){//添加元素
Element childelement = currentelement.addElement(childName); //給當(dāng)前元素添加一個(gè)子元素
childelement.setText(childValue); //設(shè)置子元素的數(shù)值
Iterator itmapAttr = mapAttr.keySet().iterator();
while(itmapAttr.hasNext()){
String key = (String) itmapAttr.next();
String value = mapAttr.get(key).toString();
childelement.setAttributeValue(key,value);
}
// childelement.setAttributeValue("id", "m1");
// childelement.setAttributeValue("name", "module1");
// childelement.setAttributeValue("url", "index1.jsp");
}else if(operator.equals("update")){//修改某個(gè)元素
List childelements = currentelement.elements(childName);//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
everyone.setText(childValue); //修改該元素值
}
}else if(operator.equals("")){ //刪除某個(gè)指定的元素
List childelements = currentelement.elements();//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
currentelement.remove(everyone);
}
}else if(operator.equals("get")){
List childelements = currentelement.elements(childName);//獲取當(dāng)前節(jié)點(diǎn)下的所有子節(jié)點(diǎn)，判斷其值，以進(jìn)行修改
for(Iterator childs=childelements.iterator();childs.hasNext();){
Element everyone = (Element)childs.next();
//result = everyone.getText();
result =everyone.attributeValue("id")+","+result ;
}
}
else{
//寫日志
// String loginfo = "XmlFile Operator not exists!";
// writelog.writeLogToEnd("LocalServerManager",loginfo);
}
}
}
}
}
}
saveXMLFile(this.document);
return result;
}
/**
* 保存XML文件
* @param document: XML文件名
*/
private void saveXMLFile(Document document) {
try {
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("utf-8");
XMLWriter writer = new XMLWriter(new FileWriter(new File(filePath)),format);
writer.write(document);
writer.close();
} catch (Exception e) {
// String loginfo = StackTraceToString.getExceptionTrace(e);
// writelog.writeLogToEnd("LocalServerManager", loginfo);
}
}
/**
* 判斷XML文件是否存在.
* @param fileName
* @return
*/
private boolean fileExist() {
java.io.File objFile = new java.io.File(this.filePath);
if (objFile.exists()) {
return true;
} else {
return false;
}
}
}
XML文件：
復(fù)制代碼 代碼如下:
解析：這里應(yīng)用遞歸的方式來判斷是對(duì)跟節(jié)點(diǎn)還是子節(jié)點(diǎn)的操作，相對(duì)比較清晰，這里用的是if判斷來判斷選擇的是那種操作，如果變動(dòng)相對(duì)較多，我感覺可以利用依賴注入，省去了if判斷的麻煩，但是當(dāng)時(shí)只是做了一個(gè)demo，沒有更多的優(yōu)化，如果有興趣的話可以試一試。
總結(jié)：讀取XML其實(shí)并不難，在寫.NET系統(tǒng)的時(shí)候就寫過關(guān)于xml的讀取，但是當(dāng)時(shí)真的就是一個(gè)一個(gè)的寫，需要什么在哪個(gè)方法下寫什么，不僅要寫很多重復(fù)的代碼，而且有一點(diǎn)問題需要重復(fù)的修改，所以，有時(shí)候，雖然實(shí)現(xiàn)了需求重要，但是怎么實(shí)現(xiàn)，同樣重要！
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