XML文档操作1
2.1、读取XML文档:
读写XML文档主要依赖于org.dom4j.io包,有DOMReader和SAXReader两种方式。因为利用了相同的接口,它们的调用方式是一样的。
public static Document load(String filename) {
Document document = null;
try {
SAXReader saxReader = new SAXReader();
document = saxReader.read(new File(filename)); //读取XML文件,获得document对象
} catch (Exception ex) {
ex.printStackTrace();
}
return document;
}
或
public static Document load(URL url) {
Document document = null;
try {
SAXReader saxReader = new SAXReader();
document = saxReader.read(url); //读取XML文件,获得document对象
} catch (Exception ex) {
ex.printStackTrace();
}
return document;
}
//读取指定的xml文件之后返回一个Document对象,这个对象代表了整个XML文档,用于各种Dom运算。执照XML文件头所定义的编码来转换。
2.2、获取根节点
根节点是xml分析的开始,任何xml分析工作都需要从根开始
Xml xml = new Xml();
Document dom = xml.load(path + "/" + file);
Element root = dom.getRootElement();
2.3、. 新增一个节点以及其下的子节点与数据
Element menuElement = root.addElement("menu");
Element engNameElement = menuElement.addElement("engName");
engNameElement.setText(catNameEn);
Element chiNameElement = menuElement.addElement("chiName");
chiNameElement.setText(catName);
2.4、 写入XML文件
注意文件操作的包装类是乱码的根源
public static boolean doc2XmlFile(Document document, String filename) {
boolean flag = true;
try {
XMLWriter writer = new XMLWriter( new OutputStreamWriter(new FileOutputStream(filename),"UTF-8"));
writer.write(document);
writer.close();
} catch (Exception ex) {
flag = false;
ex.printStackTrace();
}
System.out.println(flag);
return flag;
}
Dom4j通过XMLWriter将Document对象表示的XML树写入指定的文件,并使用OutputFormat格式对象指定写入的风格和编码方法。调用OutputFormat.createPrettyPrint()方法可以获得一个默认的pretty print风格的格式对象。对OutputFormat对象调用setEncoding()方法可以指定XML文件的编码方法。
public void writeTo(OutputStream out, String encoding) throws UnsupportedEncodingException, IOException {
OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("gb2312");
XMLWriter writer = new XMLWriter(System.out,format);
writer.write(doc);
writer.flush();
return;
}
2. 5、 遍历xml节点
对Document对象调用getRootElement()方法可以返回代表根节点的Element对象。拥有了一个Element对象后,可以对该对象调用elementIterator()方法获得它的子节点的Element对象们的一个迭代器。使用(Element)iterator.next()方法遍历一个iterator并把每个取出的元素转化为Element类型。
public boolean isOnly(String catNameEn,HttpServletRequest request,String xml) {
boolean flag = true;
String path = request.getRealPath("");
Document doc = load(path+"/"+xml);
Element root = doc.getRootElement();
for (Iterator i = root.elementIterator(); i.hasNext();) {
Element el = (Element) i.next();
if(catNameEn.equals(el.elementTextTrim("engName"))){
flag = false;
break;
}
}
return flag;
}
2.6、创建xml文件
public static void main(String args[]){
String fileName="c:/text.xml";
Document document=DocumentHelper.createDocument();//建立document对象,用来操作xml文件
Element booksElement=document.addElement("books");//建立根节点
booksElement.addComment("This is a test for dom4j ");//加入一行注释
Element bookElement=booksElement.addElement("book");//添加一个book节点
bookElement.addAttribute("show","yes");//添加属性内容
Element titleElement=bookElement.addElement("title");//添加文本节点
titleElement.setText("ajax in action");//添加文本内容
try{
XMLWriter writer=new XMLWriter(new FileWriter(new File(fileName)));
writer.close();writer.write(document);
}catch(Exception e){
e.printStackTrace();
}
}
2.7、修改节点属性
public static void modifyXMLFile() {
String oldStr = "c:/text.xml";
String newStr = "c:/text1.xml";
Document document = null;
//修改节点的属性
try {
SAXReader saxReader = new SAXReader(); // 用来读取xml文档
document = saxReader.read(new File(oldStr)); // 读取xml文档
List list = document.selectNodes("/books/book/@show");// 用xpath查找节点book的属性
Iterator iter = list.iterator();
while (iter.hasNext()) {
Attribute attribute = (Attribute) iter.next();
if (attribute.getValue().equals("yes"))
attribute.setValue("no");
}
} catch (Exception e) {
e.printStackTrace();
}
//修改节点的内容
try {
SAXReader saxReader = new SAXReader(); // 用来读取xml文档
document = saxReader.read(new File(oldStr)); // 读取xml文档
List list = document.selectNodes("/books/book/title");// 用xpath查找节点book的内容
Iterator iter = list.iterator();
while (iter.hasNext()) {
Element element = (Element) iter.next();
element.setText("xxx");// 设置相应的内容
}
} catch (Exception e) {
e.printStackTrace();
}
try {
XMLWriter writer = new XMLWriter(new FileWriter(new File(newStr)));
writer.write(document);
writer.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
2.8、删除节点
public static void removeNode() {
String oldStr = "c:/text.xml";
String newStr = "c:/text1.xml";
Document document = null;
try {
SAXReader saxReader = new SAXReader();// 用来读取xml文档
document = saxReader.read(new File(oldStr));// 读取xml文档
List list = document.selectNodes("/books/book");// 用xpath查找对象
Iterator iter = list.iterator();
while (iter.hasNext()) {
Element bookElement = (Element) iter.next();
// 创建迭代器,用来查找要删除的节点,迭代器相当于指针,指向book下所有的title节点
Iterator iterator = bookElement.elementIterator("title");
while (iterator.hasNext()) {
Element titleElement = (Element) iterator.next();
if (titleElement.getText().equals("ajax in action")) {
bookElement.remove(titleElement);
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
try {
XMLWriter writer = new XMLWriter(new FileWriter(new File(newStr)));
writer.write(document);
writer.close();
} catch (Exception ex) {
ex.printStackTrace();
}
}
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