java解析XML几种方式小结
第一种:DOM。
DOM的全称是Document Object Model,也即文档对象模型。在应用程序中,基于DOM的XML分析器将一个XML文档转换成一个对象模型的集合(通常称DOM树),应用程序正是通过对这个对象模型的操作,来实现对XML文档数据的操作。通过DOM接口,应用程序可以在任何时候访问XML文档中的任何一部分数据,因此,这种利用DOM接口的机制也被称作随机访问机制。
DOM接口提供了一种通过分层对象模型来访问XML文档信息的方式,这些分层对象模型依据XML的文档结构形成了一棵节点树。无论XML文档中所描述的是什么类型的信息,即便是制表数据、项目列表或一个文档,利用DOM所生成的模型都是节点树的形式。也就是说,DOM强制使用树模型来访问XML文档中的信息。由于XML本质上就是一种分层结构,所以这种描述方法是相当有效的。
DOM树所提供的随机访问方式给应用程序的开发带来了很大的灵活性,它可以任意地控制整个XML文档中的内容。然而,由于DOM分析器把整个XML文档转化成DOM树放在了内存中,因此,当文档比较大或者结构比较复杂时,对内存的需求就比较高。而且,对于结构复杂的树的遍历也是一项耗时的操作。所以,DOM分析器对机器性能的要求比较高,实现效率不十分理想。不过,由于DOM分析器所采用的树结构的思想与XML文档的结构相吻合,同时鉴于随机访问所带来的方便,因此,DOM分析器还是有很广泛的使用价值的。
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import
java.io.File;
import
javax.xml.parsers.DocumentBuilder;
import
javax.xml.parsers.DocumentBuilderFactory;
import
org.w3c.dom.Document;
import
org.w3c.dom.Element;
import
org.w3c.dom.NodeList;
public
class DomTest1
{ public
static void
main(String[] args) throws
Exception
{
// step 1: 获得dom解析器工厂(工作的作用是用于创建具体的解析器)
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
// System.out.println("class name: " + dbf.getClass().getName());
// step 2:获得具体的dom解析器
DocumentBuilder db = dbf.newDocumentBuilder();
// System.out.println("class name: " + db.getClass().getName());
// step3: 解析一个xml文档,获得Document对象(根结点)
Document document = db.parse( new
File( "candidate.xml" ));
NodeList list = document.getElementsByTagName( "PERSON" );
for ( int
i = 0 ; i < list.getLength(); i++)
{
Element element = (Element)list.item(i);
String content = element.getElementsByTagName( "NAME" ).item( 0 ).getFirstChild().getNodeValue();
System.out.println( "name:"
+ content);
content = element.getElementsByTagName( "ADDRESS" ).item( 0 ).getFirstChild().getNodeValue();
System.out.println( "address:"
+ content);
content = element.getElementsByTagName( "TEL" ).item( 0 ).getFirstChild().getNodeValue();
System.out.println( "tel:"
+ content);
content = element.getElementsByTagName( "FAX" ).item( 0 ).getFirstChild().getNodeValue();
System.out.println( "fax:"
+ content);
content = element.getElementsByTagName( "EMAIL" ).item( 0 ).getFirstChild().getNodeValue();
System.out.println( "email:"
+ content);
System.out.println( "--------------------------------------" );
}
}
} |
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import
java.io.File;
import
javax.xml.parsers.DocumentBuilder;
import
javax.xml.parsers.DocumentBuilderFactory;
import
org.w3c.dom.Attr;
import
org.w3c.dom.Comment;
import
org.w3c.dom.Document;
import
org.w3c.dom.Element;
import
org.w3c.dom.NamedNodeMap;
import
org.w3c.dom.Node;
import
org.w3c.dom.NodeList;
/**
* 使用递归解析给定的任意一个xml文档并且将其内容输出到命令行上
* @author zhanglong
*
*/
public
class DomTest3
{ public
static void
main(String[] args) throws
Exception
{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse( new
File( "student.xml" ));
//获得根元素结点
Element root = doc.getDocumentElement();
parseElement(root);
}
private
static void
parseElement(Element element)
{
String tagName = element.getNodeName();
NodeList children = element.getChildNodes();
System.out.print( "<"
+ tagName);
//element元素的所有属性所构成的NamedNodeMap对象,需要对其进行判断
NamedNodeMap map = element.getAttributes();
//如果该元素存在属性
if ( null
!= map)
{
for ( int
i = 0 ; i < map.getLength(); i++)
{
//获得该元素的每一个属性
Attr attr = (Attr)map.item(i);
String attrName = attr.getName();
String attrValue = attr.getValue();
System.out.print( " "
+ attrName + "=\""
+ attrValue + "\"" );
}
}
System.out.print( ">" );
for ( int
i = 0 ; i < children.getLength(); i++)
{
Node node = children.item(i);
//获得结点的类型
short
nodeType = node.getNodeType();
if (nodeType == Node.ELEMENT_NODE)
{
//是元素,继续递归
parseElement((Element)node);
}
else
if (nodeType == Node.TEXT_NODE)
{
//递归出口
System.out.print(node.getNodeValue());
}
else
if (nodeType == Node.COMMENT_NODE)
{
System.out.print( "<!--" );
Comment comment = (Comment)node;
//注释内容
String data = comment.getData();
System.out.print(data);
System.out.print( "-->" );
}
}
System.out.print( "</"
+ tagName + ">" );
}
} |
sax:SAX的全称是Simple APIs for XML,也即XML简单应用程序接口。与DOM不同,SAX提供的访问模式是一种顺序模式,这是一种快速读写XML数据的方式。当使用SAX分析器对XML文档进行分析时,会触发一系列事件,并激活相应的事件处理函数,应用程序通过这些事件处理函数实现对XML文档的访问,因而SAX接口也被称作事件驱动接口。
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import
java.io.File;
import
javax.xml.parsers.SAXParser;
import
javax.xml.parsers.SAXParserFactory;
import
org.xml.sax.Attributes;
import
org.xml.sax.SAXException;
import
org.xml.sax.helpers.DefaultHandler;
public
class SaxTest1
{ public
static void
main(String[] args) throws
Exception
{
//step1: 获得SAX解析器工厂实例
SAXParserFactory factory = SAXParserFactory.newInstance();
//step2: 获得SAX解析器实例
SAXParser parser = factory.newSAXParser();
//step3: 开始进行解析
parser.parse( new
File( "student.xml" ),
new MyHandler());
}
} class
MyHandler extends
DefaultHandler
{ @Override
public
void startDocument()
throws SAXException
{
System.out.println( "parse began" );
}
@Override
public
void endDocument()
throws SAXException
{
System.out.println( "parse finished" );
}
@Override
public
void startElement(String uri, String localName, String qName,
Attributes attributes)
throws SAXException
{
System.out.println( "start element" );
}
@Override
public
void endElement(String uri, String localName, String qName)
throws
SAXException
{
System.out.println( "finish element" );
}
} |
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import
java.io.File;
import
java.util.Stack;
import
javax.xml.parsers.SAXParser;
import
javax.xml.parsers.SAXParserFactory;
import
org.xml.sax.Attributes;
import
org.xml.sax.SAXException;
import
org.xml.sax.helpers.DefaultHandler;
public
class SaxTest2
{ public
static void
main(String[] args) throws
Exception
{
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
parser.parse( new
File( "student.xml" ),
new MyHandler2());
}
} class
MyHandler2 extends
DefaultHandler
{ private
Stack<String> stack = new
Stack<String>();
private
String name;
private
String gender;
private
String age;
@Override
public
void startElement(String uri, String localName, String qName,
Attributes attributes)
throws SAXException
{
stack.push(qName);
for ( int
i = 0 ; i < attributes.getLength(); i++)
{
String attrName = attributes.getQName(i);
String attrValue = attributes.getValue(i);
System.out.println(attrName +
"=" + attrValue);
}
}
@Override
public
void characters( char [] ch,
int start,
int length)
throws
SAXException
{
String tag = stack.peek();
if ( "姓名" .equals(tag))
{
name =
new String(ch, start,length);
}
else
if ( "性别" .equals(tag))
{
gender =
new String(ch, start, length);
}
else
if ( "年龄" .equals(tag))
{
age =
new String(ch, start, length);
}
}
@Override
public
void endElement(String uri, String localName, String qName)
throws
SAXException
{
stack.pop();
//表示该元素已经解析完毕,需要从栈中弹出
if ( "学生" .equals(qName))
{
System.out.println( "姓名:"
+ name);
System.out.println( "性别:"
+ gender);
System.out.println( "年龄:"
+ age);
System.out.println();
}
}
} |
JDOM:
JDOM是一个开源项目,它基于树型结构,利用纯JAVA的技术对XML文档实现解析、生成、序列化以及多种操作。(http://jdom.org)
•JDOM 直接为JAVA编程服务。它利用更为强有力的JAVA语言的诸多特性(方法重载、集合概念等),把SAX和DOM的功能有效地结合起来。
•JDOM是用Java语言读、写、操作XML的新API函数。在直接、简单和高效的前提下,这些API函数被最大限度的优化。
jdom创建xml
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import
java.io.FileWriter;
import
org.jdom.Attribute;
import
org.jdom.Comment;
import
org.jdom.Document;
import
org.jdom.Element;
import
org.jdom.output.Format;
import
org.jdom.output.XMLOutputter;
public
class JDomTest1
{ public
static void
main(String[] args) throws
Exception
{
Document document =
new Document();
Element root =
new Element( "root" );
document.addContent(root);
Comment comment =
new Comment( "This is my comments" );
root.addContent(comment);
Element e =
new Element( "hello" );
e.setAttribute( "sohu" ,
"www.sohu.com" );
root.addContent(e);
Element e2 =
new Element( "world" );
Attribute attr =
new Attribute( "test" ,
"hehe" );
e2.setAttribute(attr);
e.addContent(e2);
e2.addContent( new
Element( "aaa" ).setAttribute( "a" ,
"b" )
.setAttribute( "x" ,
"y" ).setAttribute( "gg" ,
"hh" ).setText( "text content" ));
Format format = Format.getPrettyFormat();
format.setIndent( " " );
// format.setEncoding("gbk");
XMLOutputter out =
new XMLOutputter(format);
out.output(document,
new FileWriter( "jdom.xml" ));
}
} |
JDOM解析xml
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import
java.io.File;
import
java.io.FileOutputStream;
import
java.util.List;
import
org.jdom.Attribute;
import
org.jdom.Document;
import
org.jdom.Element;
import
org.jdom.input.SAXBuilder;
import
org.jdom.output.Format;
import
org.jdom.output.XMLOutputter;
public
class JDomTest2
{ public
static void
main(String[] args) throws
Exception
{
SAXBuilder builder =
new SAXBuilder();
Document doc = builder.build( new
File( "jdom.xml" ));
Element element = doc.getRootElement();
System.out.println(element.getName());
Element hello = element.getChild( "hello" );
System.out.println(hello.getText());
List list = hello.getAttributes();
for ( int
i = 0
;i < list.size(); i++)
{
Attribute attr = (Attribute)list.get(i);
String attrName = attr.getName();
String attrValue = attr.getValue();
System.out.println(attrName +
"=" + attrValue);
}
hello.removeChild( "world" );
XMLOutputter out =
new XMLOutputter(Format.getPrettyFormat().setIndent( " " ));
out.output(doc,
new FileOutputStream( "jdom2.xml" ));
}
} |
Dom4j
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import
java.io.FileOutputStream;
import
java.io.FileWriter;
import
org.dom4j.Document;
import
org.dom4j.DocumentHelper;
import
org.dom4j.Element;
import
org.dom4j.io.OutputFormat;
import
org.dom4j.io.XMLWriter;
public
class Test1
{ public
static void
main(String[] args) throws
Exception
{
// 创建文档并设置文档的根元素节点 :第一种方式
// Document document = DocumentHelper.createDocument();
//
// Element root = DocumentHelper.createElement("student");
//
// document.setRootElement(root);
// 创建文档并设置文档的根元素节点 :第二种方式
Element root = DocumentHelper.createElement( "student" );
Document document = DocumentHelper.createDocument(root);
root.addAttribute( "name" ,
"zhangsan" );
Element helloElement = root.addElement( "hello" );
Element worldElement = root.addElement( "world" );
helloElement.setText( "hello" );
worldElement.setText( "world" );
helloElement.addAttribute( "age" ,
"20" );
XMLWriter xmlWriter =
new XMLWriter();
xmlWriter.write(document);
OutputFormat format =
new OutputFormat( " " ,
true );
XMLWriter xmlWriter2 =
new XMLWriter( new
FileOutputStream( "student2.xml" ), format);
xmlWriter2.write(document);
XMLWriter xmlWriter3 =
new XMLWriter( new
FileWriter( "student3.xml" ), format);
xmlWriter3.write(document);
xmlWriter3.close();
}
} |
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import
java.io.File;
import
java.util.Iterator;
import
java.util.List;
import
javax.xml.parsers.DocumentBuilder;
import
javax.xml.parsers.DocumentBuilderFactory;
import
org.dom4j.Document;
import
org.dom4j.Element;
import
org.dom4j.io.DOMReader;
import
org.dom4j.io.SAXReader;
public
class Test2
{ public
static void
main(String[] args) throws
Exception
{
SAXReader saxReader =
new SAXReader();
Document doc = saxReader.read( new
File( "student2.xml" ));
Element root = doc.getRootElement();
System.out.println( "root element: "
+ root.getName());
List childList = root.elements();
System.out.println(childList.size());
List childList2 = root.elements( "hello" );
System.out.println(childList2.size());
Element first = root.element( "hello" );
System.out.println(first.attributeValue( "age" ));
for (Iterator iter = root.elementIterator(); iter.hasNext();)
{
Element e = (Element)iter.next();
System.out.println(e.attributeValue( "age" ));
}
System.out.println( "---------------------------" );
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
org.w3c.dom.Document document = db.parse( new
File( "student2.xml" ));
DOMReader domReader =
new DOMReader();
//将JAXP的Document转换为dom4j的Document
Document d = domReader.read(document);
Element rootElement = d.getRootElement();
System.out.println(rootElement.getName());
}
} |
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import
java.io.FileWriter;
import
org.jdom.Attribute;
import
org.jdom.Document;
import
org.jdom.Element;
import
org.jdom.output.Format;
import
org.jdom.output.XMLOutputter;
public
class Test3
{ public
static void
main(String[] args) throws
Exception
{
Document document =
new Document();
Element root =
new Element( "联系人列表" ).setAttribute( new
Attribute( "公司" ,
"A集团" ));
document.addContent(root);
Element contactPerson =
new Element( "联系人" );
root.addContent(contactPerson);
contactPerson
.addContent( new
Element( "姓名" ).setText( "张三" ))
.addContent( new
Element( "公司" ).setText( "A公司" ))
.addContent( new
Element( "电话" ).setText( "021-55556666" ))
.addContent(
new
Element( "地址" )
.addContent( new
Element( "街道" ).setText( "5街" ))
.addContent( new
Element( "城市" ).setText( "上海" ))
.addContent( new
Element( "省份" ).setText( "上海市" )));
XMLOutputter output =
new XMLOutputter(Format.getPrettyFormat()
.setIndent( " " ).setEncoding( "gbk" ));
output.output(document,
new FileWriter( "contact.xml" ));
}
} |