dom4j读写xml文件

dom4j读写xml文件

首先我们给出一段示例程序：

importjava.io.File;
importjava.io.FileWriter;
importjava.util.Iterator;

importorg.dom4j.Document;
importorg.dom4j.DocumentHelper;
importorg.dom4j.Element;
importorg.dom4j.io.OutputFormat;
importorg.dom4j.io.SAXReader;
importorg.dom4j.io.XMLWriter;

publicclassDOM4JTest{

/***/
/***/
/***/
/**
*DOM4J读写XML示例
*
*@paramargs
*@throwsException
*/
publicstaticvoidmain(String[]args){
try{
XMLWriterwriter=null;//声明写XML的对象
SAXReaderreader=newSAXReader();

OutputFormatformat=OutputFormat.createPrettyPrint();
format.setEncoding("GBK");//设置XML文件的编码格式

StringfilePath="d://student.xml";
Filefile=newFile(filePath);
if(file.exists()){
Documentdocument=reader.read(file);//读取XML文件
Elementroot=document.getRootElement();//得到根节点
booleanbl=false;
for(Iteratori=root.elementIterator("学生");i.hasNext();){
Elementstudent=(Element)i.next();
if(student.attributeValue("sid").equals("001")){
//修改学生sid=001的学生信息
student.selectSingleNode("姓名").setText("王五");
student.selectSingleNode("年龄").setText("25");

writer=newXMLWriter(newFileWriter(filePath),format);
writer.write(document);
writer.close();
bl=true;
break;
}
}
if(bl){
//添加一个学生信息
Elementstudent=root.addElement("学生");
student.addAttribute("sid","100");
Elementsid=student.addElement("编号");
sid.setText("100");
Elementname=student.addElement("姓名");
name.setText("嘎嘎");
Elementsex=student.addElement("性别");
sex.setText("男");
Elementage=student.addElement("年龄");
age.setText("21");

writer=newXMLWriter(newFileWriter(filePath),format);
writer.write(document);
writer.close();
}
}else{
//新建student.xml文件并新增内容
Document_document=DocumentHelper.createDocument();
Element_root=_document.addElement("学生信息");
Element_student=_root.addElement("学生");
_student.addAttribute("sid","001");
Element_id=_student.addElement("编号");
_id.setText("001");
Element_name=_student.addElement("姓名");
_name.setText("灰机");
Element_age=_student.addElement("年龄");
_age.setText("18");

writer=newXMLWriter(newFileWriter(file),format);
writer.write(_document);
writer.close();
}
System.out.println("操作结束!");
}catch(Exceptione){
e.printStackTrace();
}

}
}

执行结果应该是这样：



循环解析节点：

privatevoidgetAllNodes(Stringxml){
try{
Documentauthtmp=DocumentHelper.parseText(xml);
List<Element>list=authtmp.selectNodes("//sms/node");
for(intj=0;j<list.size();j++){
Elementnode=(Element)list.get(j);
nodeByNodes(node);
}
}catch(Exceptione){
e.printStackTrace();
}
}

privatevoidnodeByNodes(Elementnode){
if(node.element("node")!=null){
Stringid=node.attributeValue("id");
Stringname=node.attributeValue("name");
System.out.print(id+"-------");
System.out.println(name);
for(Iteratori=node.elementIterator("node");i.hasNext();){
ElementnewNode=(Element)i.next();
nodeByNodes(newNode);
}
}else{
Stringid=node.attributeValue("id");
Stringname=node.attributeValue("name");
System.out.print(id+"-------");
System.out.println(name);
}
}

其次DOM4J的解释

一.Document对象相关

1.读取XML文件,获得document对象.

SAXReaderreader= newSAXReader();
Documentdocument = reader.read( new File( " input.xml " ));

2.解析XML形式的文本,得到document对象.

Stringtext = " <members></members> ";
Documentdocument = DocumentHelper.parseText(text);

3.主动创建document对象.

Documentdocument =DocumentHelper.createDocument();
Elementroot = document.addElement( " members " ); // 创建根节点

二.节点相关

1.获取文档的根节点.

ElementrootElm = document.getRootElement();

2.取得某节点的单个子节点.

ElementmemberElm = root.element( " member " ); // "member"是节点名

3.取得节点的文字

String text = memberElm.getText();

也可以用:

String text = root.elementText( " name " );

这个是取得根节点下的name字节点的文字.

4.取得某节点下名为"member"的所有字节点并进行遍历.

Listnodes = rootElm.elements( " member ");

for (Iteratorit = nodes.iterator();it.hasNext();) {
Elementelm=(Element)it.next();
//dosomething
}

5.对某节点下的所有子节点进行遍历.

for (Iteratorit = root.elementIterator();it.hasNext();) {
Elementelement=(Element)it.next();
//dosomething
}

6.在某节点下添加子节点.

Element ageElm = newMemberElm.addElement( " age " );

7.设置节点文字.

ageElm.setText( " 29 " );

8.删除某节点.

parentElm.remove(childElm); // childElm是待删除的节点,parentElm是其父节点

9.添加一个CDATA节点.

Element contentElm = infoElm.addElement( " content " );
contentElm.addCDATA(diary.getContent());

contentElm.getText();//特别说明：获取节点的CDATA值与获取节点的值是一个方法
contentElm.clearContent();//清除节点中的内容，CDATA亦可

三.属性相关.
1.取得某节点下的某属性

Element root = document.getRootElement();
Attribute attribute = root.attribute( " size " ); // 属性名name

2.取得属性的文字

String text = attribute.getText();

也可以用:

String text2 = root.element( " name " ).attributeValue( " firstname " );

这个是取得根节点下name字节点的属性firstname的值.

3.遍历某节点的所有属性

Elementroot = document.getRootElement();
for (Iteratorit = root.attributeIterator();it.hasNext();) {
Attributeattribute=(Attribute)it.next();
Stringtext=attribute.getText();
System.out.println(text);
}

4.设置某节点的属性和文字.

newMemberElm.addAttribute( " name " , " sitinspring " );

5.设置属性的文字

Attribute attribute = root.attribute( " name " );
attribute.setText( " sitinspring " );

6.删除某属性

Attribute attribute = root.attribute( " size " ); // 属性名name
root.remove(attribute);

四.将文档写入XML文件.
1.文档中全为英文,不设置编码,直接写入的形式.

XMLWriter writer = new XMLWriter( new FileWriter( " output.xml " ));
writer.write(document);
writer.close();

2.文档中含有中文,设置编码格式写入的形式.

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding( " GBK " ); // 指定XML编码
XMLWriter writer = new XMLWriter( new FileWriter( " output.xml " ),format);

writer.write(document);
writer.close();

五.字符串与XML的转换
1.将字符串转化为XML

String text = " <members> <member>sitinspring</member> </members> " ;
Document document = DocumentHelper.parseText(text);

2.将文档或节点的XML转化为字符串.

SAXReader reader = new SAXReader();
Document document = reader.read( new File( " input.xml " ));
Element root = document.getRootElement();
String docXmlText = document.asXML();
String rootXmlText = root.asXML();
Element memberElm = root.element( " member " );
String memberXmlText = memberElm.asXML();