java解析xml汇总

【目录】

一、【基础知识——扫盲】

二、【DOM、SAX、JDOM、DOM4j简单使用介绍】

三、【性能测试】

四、【对比】

五、【小插曲XPath】

六、【补充】

关键字：Java解析xml、解析xml四种方法、DOM、SAX、JDOM、DOM4j、XPath

【引言】

目前在Java中用于解析XML的技术很多，主流的有DOM、SAX、JDOM、DOM4j，下文主要介绍这4种解析XML文档技术的使用、优缺点及性能测试。

一、【基础知识——扫盲】

sax、dom是两种对xml文档进行解析的方法(没有具体实现，只是接口)，所以只有它们是无法解析xml文档的；jaxp只是api，它进一步封装了sax、dom两种接口，并且提供了DomcumentBuilderFactory/DomcumentBuilder和SAXParserFactory/SAXParser（默认使用xerces解释器）。

二、【DOM、SAX、JDOM、DOM4j简单使用介绍】

1、【DOM(Document Object Model) 】
由W3C提供的接口，它将整个XML文档读入内存，构建一个DOM树来对各个节点(Node)进行操作。
示例代码：

[html] view plaincopyprint?

1. <?xml version="1.0" encoding="UTF-8"?> 
2. <university name="pku"> 
3.     <college name="c1"> 
4.         <class name="class1"> 
5.             <student name="stu1" sex='male' age="21" /> 
6.             <student name="stu2" sex='female' age="20" /> 
7.             <student name="stu3" sex='female' age="20" /> 
8.         </class> 
9.         <class name="class2"> 
10.             <student name="stu4" sex='male' age="19" /> 
11.             <student name="stu5" sex='female' age="20" /> 
12.             <student name="stu6" sex='female' age="21" /> 
13.         </class> 
14.     </college> 
15.     <college name="c2"> 
16.         <class name="class3"> 
17.             <student name="stu7" sex='male' age="20" /> 
18.         </class> 
19.     </college> 
20.     <college name="c3"> 
21.     </college> 
22. </university> 

<?xml version="1.0" encoding="UTF-8"?> <university name="pku"> <college name="c1"> <class name="class1"> <student name="stu1" sex='male' age="21" /> <student name="stu2" sex='female' age="20" /> <student name="stu3" sex='female' age="20" /> </class> <class name="class2"> <student name="stu4" sex='male' age="19" /> <student name="stu5" sex='female' age="20" /> <student name="stu6" sex='female' age="21" /> </class> </college> <college name="c2"> <class name="class3"> <student name="stu7" sex='male' age="20" /> </class> </college> <college name="c3"> </college> </university>后文代码中有使用到text.xml（该文档放在src路径下，既编译后在classes路径下），都是指该xml文档。

[java] view plaincopyprint?

1. package test.xml; 
2.  
3. import java.io.File; 
4. import java.io.FileNotFoundException; 
5. import java.io.FileOutputStream; 
6. import java.io.IOException; 
7. import java.io.InputStream; 
8.  
9. import javax.xml.parsers.DocumentBuilder; 
10. import javax.xml.parsers.DocumentBuilderFactory; 
11. import javax.xml.parsers.ParserConfigurationException; 
12. import javax.xml.transform.Transformer; 
13. import javax.xml.transform.TransformerConfigurationException; 
14. import javax.xml.transform.TransformerException; 
15. import javax.xml.transform.TransformerFactory; 
16. import javax.xml.transform.dom.DOMSource; 
17. import javax.xml.transform.stream.StreamResult; 
18.  
19. import org.w3c.dom.Document; 
20. import org.w3c.dom.Element; 
21. import org.w3c.dom.Node; 
22. import org.w3c.dom.NodeList; 
23. import org.w3c.dom.Text; 
24. import org.xml.sax.SAXException; 
25.  
26. /**
27. * dom读写xml
28. * @author whwang
29. */ 
30. public class TestDom { 
31.      
32.     public static void main(String[] args) { 
33.         read(); 
34.         //write();  
35.     } 
36.      
37.     public static void read() { 
38.         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
39.         try { 
40.             DocumentBuilder builder = dbf.newDocumentBuilder(); 
41.             InputStream in = TestDom.class.getClassLoader().getResourceAsStream("test.xml"); 
42.             Document doc = builder.parse(in); 
43.             // root <university>  
44.             Element root = doc.getDocumentElement(); 
45.             if (root == null) return; 
46.             System.err.println(root.getAttribute("name")); 
47.             // all college node  
48.             NodeList collegeNodes = root.getChildNodes(); 
49.             if (collegeNodes == null) return; 
50.             for(int i = 0; i < collegeNodes.getLength(); i++) { 
51.                 Node college = collegeNodes.item(i); 
52.                 if (college != null && college.getNodeType() == Node.ELEMENT_NODE) { 
53.                     System.err.println("\t" + college.getAttributes().getNamedItem("name").getNodeValue()); 
54.                     // all class node  
55.                     NodeList classNodes = college.getChildNodes(); 
56.                     if (classNodes == null) continue; 
57.                     for (int j = 0; j < classNodes.getLength(); j++) { 
58.                         Node clazz = classNodes.item(j); 
59.                         if (clazz != null && clazz.getNodeType() == Node.ELEMENT_NODE) { 
60.                             System.err.println("\t\t" + clazz.getAttributes().getNamedItem("name").getNodeValue()); 
61.                             // all student node  
62.                             NodeList studentNodes = clazz.getChildNodes(); 
63.                             if (studentNodes == null) continue; 
64.                             for (int k = 0; k < studentNodes.getLength(); k++) { 
65.                                 Node student = studentNodes.item(k); 
66.                                 if (student != null && student.getNodeType() == Node.ELEMENT_NODE) { 
67.                                     System.err.print("\t\t\t" + student.getAttributes().getNamedItem("name").getNodeValue()); 
68.                                     System.err.print(" " + student.getAttributes().getNamedItem("sex").getNodeValue()); 
69.                                     System.err.println(" " + student.getAttributes().getNamedItem("age").getNodeValue()); 
70.                                 } 
71.                             } 
72.                         } 
73.                     } 
74.                 } 
75.             } 
76.         } catch (ParserConfigurationException e) { 
77.             e.printStackTrace(); 
78.         } catch (FileNotFoundException e) { 
79.             e.printStackTrace(); 
80.         } catch (SAXException e) { 
81.             e.printStackTrace(); 
82.         } catch (IOException e) { 
83.             e.printStackTrace(); 
84.         } 
85.          
86.     } 
87.      
88.     public static void write() { 
89.         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
90.         try { 
91.             DocumentBuilder builder = dbf.newDocumentBuilder(); 
92.             InputStream in = TestDom.class.getClassLoader().getResourceAsStream("test.xml"); 
93.             Document doc = builder.parse(in); 
94.             // root <university>  
95.             Element root = doc.getDocumentElement(); 
96.             if (root == null) return; 
97.             // 修改属性  
98.             root.setAttribute("name", "tsu"); 
99.             NodeList collegeNodes = root.getChildNodes(); 
100.             if (collegeNodes != null) { 
101.                 for (int i = 0; i <collegeNodes.getLength() - 1; i++) { 
102.                     // 删除节点  
103.                     Node college = collegeNodes.item(i); 
104.                     if (college.getNodeType() == Node.ELEMENT_NODE) { 
105.                         String collegeName = college.getAttributes().getNamedItem("name").getNodeValue(); 
106.                         if ("c1".equals(collegeName) || "c2".equals(collegeName)) { 
107.                             root.removeChild(college); 
108.                         } else if ("c3".equals(collegeName)) { 
109.                             Element newChild = doc.createElement("class"); 
110.                             newChild.setAttribute("name", "c4"); 
111.                             college.appendChild(newChild); 
112.                         } 
113.                     } 
114.                 } 
115.             } 
116.             // 新增节点  
117.             Element addCollege = doc.createElement("college"); 
118.             addCollege.setAttribute("name", "c5"); 
119.             root.appendChild(addCollege); 
120.             Text text = doc.createTextNode("text"); 
121.             addCollege.appendChild(text); 
122.              
123.             // 将修改后的文档保存到文件  
124.             TransformerFactory transFactory = TransformerFactory.newInstance(); 
125.             Transformer transFormer = transFactory.newTransformer(); 
126.             DOMSource domSource = new DOMSource(doc); 
127.             File file = new File("src/dom-modify.xml"); 
128.             if (file.exists()) { 
129.                 file.delete(); 
130.             } 
131.             file.createNewFile(); 
132.             FileOutputStream out = new FileOutputStream(file);          
133.             StreamResult xmlResult = new StreamResult(out); 
134.             transFormer.transform(domSource, xmlResult); 
135.             System.out.println(file.getAbsolutePath()); 
136.         } catch (ParserConfigurationException e) { 
137.             e.printStackTrace(); 
138.         } catch (SAXException e) { 
139.             e.printStackTrace(); 
140.         } catch (IOException e) { 
141.             e.printStackTrace(); 
142.         } catch (TransformerConfigurationException e) { 
143.             e.printStackTrace(); 
144.         } catch (TransformerException e) { 
145.             e.printStackTrace(); 
146.         } 
147.     } 
148. } 

package test.xml; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerConfigurationException; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.w3c.dom.Text; import org.xml.sax.SAXException; /** * dom读写xml * @author whwang */ public class TestDom { public static void main(String[] args) { read(); //write(); } public static void read() { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); try { DocumentBuilder builder = dbf.newDocumentBuilder(); InputStream in = TestDom.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = builder.parse(in); // root <university> Element root = doc.getDocumentElement(); if (root == null) return; System.err.println(root.getAttribute("name")); // all college node NodeList collegeNodes = root.getChildNodes(); if (collegeNodes == null) return; for(int i = 0; i < collegeNodes.getLength(); i++) { Node college = collegeNodes.item(i); if (college != null && college.getNodeType() == Node.ELEMENT_NODE) { System.err.println("\t" + college.getAttributes().getNamedItem("name").getNodeValue()); // all class node NodeList classNodes = college.getChildNodes(); if (classNodes == null) continue; for (int j = 0; j < classNodes.getLength(); j++) { Node clazz = classNodes.item(j); if (clazz != null && clazz.getNodeType() == Node.ELEMENT_NODE) { System.err.println("\t\t" + clazz.getAttributes().getNamedItem("name").getNodeValue()); // all student node NodeList studentNodes = clazz.getChildNodes(); if (studentNodes == null) continue; for (int k = 0; k < studentNodes.getLength(); k++) { Node student = studentNodes.item(k); if (student != null && student.getNodeType() == Node.ELEMENT_NODE) { System.err.print("\t\t\t" + student.getAttributes().getNamedItem("name").getNodeValue()); System.err.print(" " + student.getAttributes().getNamedItem("sex").getNodeValue()); System.err.println(" " + student.getAttributes().getNamedItem("age").getNodeValue()); } } } } } } } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } public static void write() { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); try { DocumentBuilder builder = dbf.newDocumentBuilder(); InputStream in = TestDom.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = builder.parse(in); // root <university> Element root = doc.getDocumentElement(); if (root == null) return; // 修改属性 root.setAttribute("name", "tsu"); NodeList collegeNodes = root.getChildNodes(); if (collegeNodes != null) { for (int i = 0; i <collegeNodes.getLength() - 1; i++) { // 删除节点 Node college = collegeNodes.item(i); if (college.getNodeType() == Node.ELEMENT_NODE) { String collegeName = college.getAttributes().getNamedItem("name").getNodeValue(); if ("c1".equals(collegeName) || "c2".equals(collegeName)) { root.removeChild(college); } else if ("c3".equals(collegeName)) { Element newChild = doc.createElement("class"); newChild.setAttribute("name", "c4"); college.appendChild(newChild); } } } } // 新增节点 Element addCollege = doc.createElement("college"); addCollege.setAttribute("name", "c5"); root.appendChild(addCollege); Text text = doc.createTextNode("text"); addCollege.appendChild(text); // 将修改后的文档保存到文件 TransformerFactory transFactory = TransformerFactory.newInstance(); Transformer transFormer = transFactory.newTransformer(); DOMSource domSource = new DOMSource(doc); File file = new File("src/dom-modify.xml"); if (file.exists()) { file.delete(); } file.createNewFile(); FileOutputStream out = new FileOutputStream(file); StreamResult xmlResult = new StreamResult(out); transFormer.transform(domSource, xmlResult); System.out.println(file.getAbsolutePath()); } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } catch (TransformerConfigurationException e) { e.printStackTrace(); } catch (TransformerException e) { e.printStackTrace(); } } }该代码只要稍做修改，即可变得更加简洁，无需一直写if来判断是否有子节点。

2、【SAX (Simple API for XML) 】
SAX不用将整个文档加载到内存，基于事件驱动的API(Observer模式)，用户只需要注册自己感兴趣的事件即可。SAX提供EntityResolver, DTDHandler, ContentHandler, ErrorHandler接口，分别用于监听解析实体事件、DTD处理事件、正文处理事件和处理出错事件，与AWT类似，SAX还提供了一个对这4个接口默认的类DefaultHandler（这里的默认实现，其实就是一个空方法），一般只要继承DefaultHandler，重写自己感兴趣的事件即可。
示例代码：

[java] view plaincopyprint?

1. package test.xml; 
2.  
3. import java.io.IOException; 
4. import java.io.InputStream; 
5.  
6. import javax.xml.parsers.ParserConfigurationException; 
7. import javax.xml.parsers.SAXParser; 
8. import javax.xml.parsers.SAXParserFactory; 
9.  
10. import org.xml.sax.Attributes; 
11. import org.xml.sax.InputSource; 
12. import org.xml.sax.Locator; 
13. import org.xml.sax.SAXException; 
14. import org.xml.sax.SAXParseException; 
15. import org.xml.sax.helpers.DefaultHandler; 
16.  
17. /**
18. *
19. * @author whwang
20. */ 
21. public class TestSAX { 
22.  
23.     public static void main(String[] args) { 
24.         read(); 
25.         write(); 
26.     } 
27.      
28.     public static void read() { 
29.         try { 
30.             SAXParserFactory factory = SAXParserFactory.newInstance(); 
31.             SAXParser parser = factory.newSAXParser(); 
32.             InputStream in = TestSAX.class.getClassLoader().getResourceAsStream("test.xml"); 
33.             parser.parse(in, new MyHandler()); 
34.         } catch (ParserConfigurationException e) { 
35.             e.printStackTrace(); 
36.         } catch (SAXException e) { 
37.             e.printStackTrace(); 
38.         } catch (IOException e) { 
39.             e.printStackTrace(); 
40.         } 
41.     } 
42.      
43.     public static void write() { 
44.         System.err.println("纯SAX对于写操作无能为力"); 
45.     } 
46.      
47. } 
48.  
49. // 重写对自己感兴趣的事件处理方法  
50. class MyHandler extends DefaultHandler { 
51.  
52.     @Override 
53.     public InputSource resolveEntity(String publicId, String systemId) 
54.             throws IOException, SAXException { 
55.         return super.resolveEntity(publicId, systemId); 
56.     } 
57.  
58.     @Override 
59.     public void notationDecl(String name, String publicId, String systemId) 
60.             throws SAXException { 
61.         super.notationDecl(name, publicId, systemId); 
62.     } 
63.  
64.     @Override 
65.     public void unparsedEntityDecl(String name, String publicId, 
66.             String systemId, String notationName) throws SAXException { 
67.         super.unparsedEntityDecl(name, publicId, systemId, notationName); 
68.     } 
69.  
70.     @Override 
71.     public void setDocumentLocator(Locator locator) { 
72.         super.setDocumentLocator(locator); 
73.     } 
74.  
75.     @Override 
76.     public void startDocument() throws SAXException { 
77.         System.err.println("开始解析文档"); 
78.     } 
79.  
80.     @Override 
81.     public void endDocument() throws SAXException { 
82.         System.err.println("解析结束"); 
83.     } 
84.  
85.     @Override 
86.     public void startPrefixMapping(String prefix, String uri) 
87.             throws SAXException { 
88.         super.startPrefixMapping(prefix, uri); 
89.     } 
90.  
91.     @Override 
92.     public void endPrefixMapping(String prefix) throws SAXException { 
93.         super.endPrefixMapping(prefix); 
94.     } 
95.  
96.     @Override 
97.     public void startElement(String uri, String localName, String qName, 
98.             Attributes attributes) throws SAXException { 
99.         System.err.print("Element: " + qName + ", attr: "); 
100.         print(attributes); 
101.     } 
102.  
103.     @Override 
104.     public void endElement(String uri, String localName, String qName) 
105.             throws SAXException { 
106.         super.endElement(uri, localName, qName); 
107.     } 
108.  
109.     @Override 
110.     public void characters(char[] ch, int start, int length) 
111.             throws SAXException { 
112.         super.characters(ch, start, length); 
113.     } 
114.  
115.     @Override 
116.     public void ignorableWhitespace(char[] ch, int start, int length) 
117.             throws SAXException { 
118.         super.ignorableWhitespace(ch, start, length); 
119.     } 
120.  
121.     @Override 
122.     public void processingInstruction(String target, String data) 
123.             throws SAXException { 
124.         super.processingInstruction(target, data); 
125.     } 
126.  
127.     @Override 
128.     public void skippedEntity(String name) throws SAXException { 
129.         super.skippedEntity(name); 
130.     } 
131.  
132.     @Override 
133.     public void warning(SAXParseException e) throws SAXException { 
134.         super.warning(e); 
135.     } 
136.  
137.     @Override 
138.     public void error(SAXParseException e) throws SAXException { 
139.         super.error(e); 
140.     } 
141.  
142.     @Override 
143.     public void fatalError(SAXParseException e) throws SAXException { 
144.         super.fatalError(e); 
145.     } 
146.      
147.     private void print(Attributes attrs) { 
148.         if (attrs == null) return; 
149.         System.err.print("["); 
150.         for (int i = 0; i < attrs.getLength(); i++) { 
151.             System.err.print(attrs.getQName(i) + " = " + attrs.getValue(i)); 
152.             if (i != attrs.getLength() - 1) { 
153.                 System.err.print(", "); 
154.             } 
155.         } 
156.         System.err.println("]"); 
157.     } 
158. } 

package test.xml; import java.io.IOException; import java.io.InputStream; import javax.xml.parsers.ParserConfigurationException; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.Attributes; import org.xml.sax.InputSource; import org.xml.sax.Locator; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import org.xml.sax.helpers.DefaultHandler; /** * * @author whwang */ public class TestSAX { public static void main(String[] args) { read(); write(); } public static void read() { try { SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser parser = factory.newSAXParser(); InputStream in = TestSAX.class.getClassLoader().getResourceAsStream("test.xml"); parser.parse(in, new MyHandler()); } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } public static void write() { System.err.println("纯SAX对于写操作无能为力"); } } // 重写对自己感兴趣的事件处理方法 class MyHandler extends DefaultHandler { @Override public InputSource resolveEntity(String publicId, String systemId) throws IOException, SAXException { return super.resolveEntity(publicId, systemId); } @Override public void notationDecl(String name, String publicId, String systemId) throws SAXException { super.notationDecl(name, publicId, systemId); } @Override public void unparsedEntityDecl(String name, String publicId, String systemId, String notationName) throws SAXException { super.unparsedEntityDecl(name, publicId, systemId, notationName); } @Override public void setDocumentLocator(Locator locator) { super.setDocumentLocator(locator); } @Override public void startDocument() throws SAXException { System.err.println("开始解析文档"); } @Override public void endDocument() throws SAXException { System.err.println("解析结束"); } @Override public void startPrefixMapping(String prefix, String uri) throws SAXException { super.startPrefixMapping(prefix, uri); } @Override public void endPrefixMapping(String prefix) throws SAXException { super.endPrefixMapping(prefix); } @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { System.err.print("Element: " + qName + ", attr: "); print(attributes); } @Override public void endElement(String uri, String localName, String qName) throws SAXException { super.endElement(uri, localName, qName); } @Override public void characters(char[] ch, int start, int length) throws SAXException { super.characters(ch, start, length); } @Override public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException { super.ignorableWhitespace(ch, start, length); } @Override public void processingInstruction(String target, String data) throws SAXException { super.processingInstruction(target, data); } @Override public void skippedEntity(String name) throws SAXException { super.skippedEntity(name); } @Override public void warning(SAXParseException e) throws SAXException { super.warning(e); } @Override public void error(SAXParseException e) throws SAXException { super.error(e); } @Override public void fatalError(SAXParseException e) throws SAXException { super.fatalError(e); } private void print(Attributes attrs) { if (attrs == null) return; System.err.print("["); for (int i = 0; i < attrs.getLength(); i++) { System.err.print(attrs.getQName(i) + " = " + attrs.getValue(i)); if (i != attrs.getLength() - 1) { System.err.print(", "); } } System.err.println("]"); } }3、【JDOM】
JDOM与DOM非常类似，它是处理XML的纯JAVA API，API大量使用了Collections类，且JDOM仅使用具体类而不使用接口。　JDOM 它自身不包含解析器。它通常使用 SAX2 解析器来解析和验证输入 XML 文档（尽管它还可以将以前构造的 DOM 表示作为输入）。它包含一些转换器以将 JDOM 表示输出成 SAX2 事件流、DOM 模型或 XML 文本文档
示例代码：

[java] view plaincopyprint?

1. package test.xml; 
2.  
3. import java.io.File; 
4. import java.io.FileOutputStream; 
5. import java.io.IOException; 
6. import java.io.InputStream; 
7. import java.util.List; 
8.  
9. import org.jdom.Attribute; 
10. import org.jdom.Document; 
11. import org.jdom.Element; 
12. import org.jdom.JDOMException; 
13. import org.jdom.input.SAXBuilder; 
14. import org.jdom.output.XMLOutputter; 
15.  
16. /**
17. * JDom读写xml
18. * @author whwang
19. */ 
20. public class TestJDom { 
21.     public static void main(String[] args) { 
22.         //read();  
23.         write(); 
24.     } 
25.      
26.     public static void read() { 
27.         try { 
28.             boolean validate = false; 
29.             SAXBuilder builder = new SAXBuilder(validate); 
30.             InputStream in = TestJDom.class.getClassLoader().getResourceAsStream("test.xml"); 
31.             Document doc = builder.build(in); 
32.             // 获取根节点 <university>  
33.             Element root = doc.getRootElement(); 
34.             readNode(root, ""); 
35.         } catch (JDOMException e) { 
36.             e.printStackTrace(); 
37.         } catch (IOException e) { 
38.             e.printStackTrace(); 
39.         } 
40.     } 
41.      
42.     @SuppressWarnings("unchecked") 
43.     public static void readNode(Element root, String prefix) { 
44.         if (root == null) return; 
45.         // 获取属性  
46.         List<Attribute> attrs = root.getAttributes(); 
47.         if (attrs != null && attrs.size() > 0) { 
48.             System.err.print(prefix); 
49.             for (Attribute attr : attrs) { 
50.                 System.err.print(attr.getValue() + " "); 
51.             } 
52.             System.err.println(); 
53.         } 
54.         // 获取他的子节点  
55.         List<Element> childNodes = root.getChildren(); 
56.         prefix += "\t"; 
57.         for (Element e : childNodes) { 
58.             readNode(e, prefix); 
59.         } 
60.     } 
61.      
62.     public static void write() { 
63.         boolean validate = false; 
64.         try { 
65.             SAXBuilder builder = new SAXBuilder(validate); 
66.             InputStream in = TestJDom.class.getClassLoader().getResourceAsStream("test.xml"); 
67.             Document doc = builder.build(in); 
68.             // 获取根节点 <university>  
69.             Element root = doc.getRootElement(); 
70.             // 修改属性  
71.             root.setAttribute("name", "tsu"); 
72.             // 删除  
73.             boolean isRemoved = root.removeChildren("college"); 
74.             System.err.println(isRemoved); 
75.             // 新增  
76.             Element newCollege = new Element("college"); 
77.             newCollege.setAttribute("name", "new_college"); 
78.             Element newClass = new Element("class"); 
79.             newClass.setAttribute("name", "ccccc"); 
80.             newCollege.addContent(newClass); 
81.             root.addContent(newCollege); 
82.             XMLOutputter out = new XMLOutputter(); 
83.             File file = new File("src/jdom-modify.xml"); 
84.             if (file.exists()) { 
85.                 file.delete(); 
86.             } 
87.             file.createNewFile(); 
88.             FileOutputStream fos = new FileOutputStream(file); 
89.             out.output(doc, fos); 
90.         } catch (JDOMException e) { 
91.             e.printStackTrace(); 
92.         } catch (IOException e) { 
93.             e.printStackTrace(); 
94.         } 
95.     } 
96.      
97. } 

package test.xml; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.List; import org.jdom.Attribute; import org.jdom.Document; import org.jdom.Element; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; import org.jdom.output.XMLOutputter; /** * JDom读写xml * @author whwang */ public class TestJDom { public static void main(String[] args) { //read(); write(); } public static void read() { try { boolean validate = false; SAXBuilder builder = new SAXBuilder(validate); InputStream in = TestJDom.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = builder.build(in); // 获取根节点 <university> Element root = doc.getRootElement(); readNode(root, ""); } catch (JDOMException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } @SuppressWarnings("unchecked") public static void readNode(Element root, String prefix) { if (root == null) return; // 获取属性 List<Attribute> attrs = root.getAttributes(); if (attrs != null && attrs.size() > 0) { System.err.print(prefix); for (Attribute attr : attrs) { System.err.print(attr.getValue() + " "); } System.err.println(); } // 获取他的子节点 List<Element> childNodes = root.getChildren(); prefix += "\t"; for (Element e : childNodes) { readNode(e, prefix); } } public static void write() { boolean validate = false; try { SAXBuilder builder = new SAXBuilder(validate); InputStream in = TestJDom.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = builder.build(in); // 获取根节点 <university> Element root = doc.getRootElement(); // 修改属性 root.setAttribute("name", "tsu"); // 删除 boolean isRemoved = root.removeChildren("college"); System.err.println(isRemoved); // 新增 Element newCollege = new Element("college"); newCollege.setAttribute("name", "new_college"); Element newClass = new Element("class"); newClass.setAttribute("name", "ccccc"); newCollege.addContent(newClass); root.addContent(newCollege); XMLOutputter out = new XMLOutputter(); File file = new File("src/jdom-modify.xml"); if (file.exists()) { file.delete(); } file.createNewFile(); FileOutputStream fos = new FileOutputStream(file); out.output(doc, fos); } catch (JDOMException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }4、【DOM4j】
dom4j是目前在xml解析方面是最优秀的(Hibernate、Sun的JAXM也都使用dom4j来解析XML)，它合并了许多超出基本 XML 文档表示的功能，包括集成的 XPath 支持、XML Schema 支持以及用于大文档或流化文档的基于事件的处理
示例代码：

[java] view plaincopyprint?

1. package test.xml; 
2.  
3. import java.io.File; 
4. import java.io.FileWriter; 
5. import java.io.IOException; 
6. import java.io.InputStream; 
7. import java.util.List; 
8.  
9. import org.dom4j.Attribute; 
10. import org.dom4j.Document; 
11. import org.dom4j.DocumentException; 
12. import org.dom4j.DocumentHelper; 
13. import org.dom4j.Element; 
14. import org.dom4j.ProcessingInstruction; 
15. import org.dom4j.VisitorSupport; 
16. import org.dom4j.io.SAXReader; 
17. import org.dom4j.io.XMLWriter; 
18.  
19. /**
20. * Dom4j读写xml
21. * @author whwang
22. */ 
23. public class TestDom4j { 
24.     public static void main(String[] args) { 
25.         read1(); 
26.         //read2();  
27.         //write();  
28.     } 
29.  
30.     public static void read1() { 
31.         try { 
32.             SAXReader reader = new SAXReader(); 
33.             InputStream in = TestDom4j.class.getClassLoader().getResourceAsStream("test.xml"); 
34.             Document doc = reader.read(in); 
35.             Element root = doc.getRootElement(); 
36.             readNode(root, ""); 
37.         } catch (DocumentException e) { 
38.             e.printStackTrace(); 
39.         } 
40.     } 
41.      
42.     @SuppressWarnings("unchecked") 
43.     public static void readNode(Element root, String prefix) { 
44.         if (root == null) return; 
45.         // 获取属性  
46.         List<Attribute> attrs = root.attributes(); 
47.         if (attrs != null && attrs.size() > 0) { 
48.             System.err.print(prefix); 
49.             for (Attribute attr : attrs) { 
50.                 System.err.print(attr.getValue() + " "); 
51.             } 
52.             System.err.println(); 
53.         } 
54.         // 获取他的子节点  
55.         List<Element> childNodes = root.elements(); 
56.         prefix += "\t"; 
57.         for (Element e : childNodes) { 
58.             readNode(e, prefix); 
59.         } 
60.     } 
61.      
62.     public static void read2() { 
63.         try { 
64.             SAXReader reader = new SAXReader(); 
65.             InputStream in = TestDom4j.class.getClassLoader().getResourceAsStream("test.xml"); 
66.             Document doc = reader.read(in); 
67.             doc.accept(new MyVistor()); 
68.         } catch (DocumentException e) { 
69.             e.printStackTrace(); 
70.         } 
71.     } 
72.      
73.     public static void write() { 
74.         try { 
75.             // 创建一个xml文档  
76.             Document doc = DocumentHelper.createDocument(); 
77.             Element university = doc.addElement("university"); 
78.             university.addAttribute("name", "tsu"); 
79.             // 注释  
80.             university.addComment("这个是根节点"); 
81.             Element college = university.addElement("college"); 
82.             college.addAttribute("name", "cccccc"); 
83.             college.setText("text"); 
84.              
85.             File file = new File("src/dom4j-modify.xml"); 
86.             if (file.exists()) { 
87.                 file.delete(); 
88.             } 
89.             file.createNewFile(); 
90.             XMLWriter out = new XMLWriter(new FileWriter(file)); 
91.             out.write(doc); 
92.             out.flush(); 
93.             out.close(); 
94.         } catch (IOException e) { 
95.             e.printStackTrace(); 
96.         } 
97.     } 
98. } 
99.  
100. class MyVistor extends VisitorSupport { 
101.     public void visit(Attribute node) { 
102.         System.out.println("Attibute: " + node.getName() + "=" 
103.                 + node.getValue()); 
104.     } 
105.  
106.     public void visit(Element node) { 
107.         if (node.isTextOnly()) { 
108.             System.out.println("Element: " + node.getName() + "=" 
109.                     + node.getText()); 
110.         } else { 
111.             System.out.println(node.getName()); 
112.         } 
113.     } 
114.  
115.     @Override 
116.     public void visit(ProcessingInstruction node) { 
117.         System.out.println("PI:" + node.getTarget() + " " + node.getText()); 
118.     } 
119. } 

package test.xml; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.util.List; import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.ProcessingInstruction; import org.dom4j.VisitorSupport; import org.dom4j.io.SAXReader; import org.dom4j.io.XMLWriter; /** * Dom4j读写xml * @author whwang */ public class TestDom4j { public static void main(String[] args) { read1(); //read2(); //write(); } public static void read1() { try { SAXReader reader = new SAXReader(); InputStream in = TestDom4j.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = reader.read(in); Element root = doc.getRootElement(); readNode(root, ""); } catch (DocumentException e) { e.printStackTrace(); } } @SuppressWarnings("unchecked") public static void readNode(Element root, String prefix) { if (root == null) return; // 获取属性 List<Attribute> attrs = root.attributes(); if (attrs != null && attrs.size() > 0) { System.err.print(prefix); for (Attribute attr : attrs) { System.err.print(attr.getValue() + " "); } System.err.println(); } // 获取他的子节点 List<Element> childNodes = root.elements(); prefix += "\t"; for (Element e : childNodes) { readNode(e, prefix); } } public static void read2() { try { SAXReader reader = new SAXReader(); InputStream in = TestDom4j.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = reader.read(in); doc.accept(new MyVistor()); } catch (DocumentException e) { e.printStackTrace(); } } public static void write() { try { // 创建一个xml文档 Document doc = DocumentHelper.createDocument(); Element university = doc.addElement("university"); university.addAttribute("name", "tsu"); // 注释 university.addComment("这个是根节点"); Element college = university.addElement("college"); college.addAttribute("name", "cccccc"); college.setText("text"); File file = new File("src/dom4j-modify.xml"); if (file.exists()) { file.delete(); } file.createNewFile(); XMLWriter out = new XMLWriter(new FileWriter(file)); out.write(doc); out.flush(); out.close(); } catch (IOException e) { e.printStackTrace(); } } } class MyVistor extends VisitorSupport { public void visit(Attribute node) { System.out.println("Attibute: " + node.getName() + "=" + node.getValue()); } public void visit(Element node) { if (node.isTextOnly()) { System.out.println("Element: " + node.getName() + "=" + node.getText()); } else { System.out.println(node.getName()); } } @Override public void visit(ProcessingInstruction node) { System.out.println("PI:" + node.getTarget() + " " + node.getText()); } }

三、【性能测试】

环境：AMD4400+ 2.0+GHz主频 JDK6.0
运行参数：-Xms400m -Xmx400m
xml文件大小：10.7M
结果：
DOM: >581297ms
SAX: 8829ms
JDOM: 581297ms
DOM4j: 5309ms
时间包括IO的，只是进行了简单的测试，仅供参考！！！！

四、【对比】

1、【DOM】
DOM是基于树的结构，通常需要加载整文档和构造DOM树，然后才能开始工作。
优点：
    a、由于整棵树在内存中，因此可以对xml文档随机访问
    b、可以对xml文档进行修改操作
    c、较sax，dom使用也更简单。
缺点：
    a、整个文档必须一次性解析完
    a、由于整个文档都需要载入内存，对于大文档成本高
2、【SAX】
SAX类似流媒体，它基于事件驱动的，因此无需将整个文档载入内存，使用者只需要监听自己感兴趣的事件即可。
优点：
    a、无需将整个xml文档载入内存，因此消耗内存少
    b、可以注册多个ContentHandler
缺点：
    a、不能随机的访问xml中的节点
    b、不能修改文档
3、【JDOM】
JDOM是纯Java的处理XML的API，其API中大量使用Collections类，
优点：
    a、DOM方式的优点
    b、具有SAX的Java规则
缺点
    a、DOM方式的缺点
4、【DOM4J】
这4中xml解析方式中，最优秀的一个，集易用和性能于一身。

五、【小插曲XPath】

XPath 是一门在 XML 文档中查找信息的语言， 可用来在 XML 文档中对元素和属性进行遍历。XPath 是 W3C XSLT 标准的主要元素，并且 XQuery 和 XPointer 同时被构建于 XPath 表达之上。因此，对 XPath 的理解是很多高级 XML 应用的基础。
XPath非常类似对数据库操作的SQL语言，或者说JQuery，它可以方便开发者抓起文档中需要的东西。（dom4j也支持xpath）
示例代码：

[java] view plaincopyprint?

1. package test.xml; 
2.  
3. import java.io.IOException; 
4. import java.io.InputStream; 
5.  
6. import javax.xml.parsers.DocumentBuilder; 
7. import javax.xml.parsers.DocumentBuilderFactory; 
8. import javax.xml.parsers.ParserConfigurationException; 
9. import javax.xml.xpath.XPath; 
10. import javax.xml.xpath.XPathConstants; 
11. import javax.xml.xpath.XPathExpression; 
12. import javax.xml.xpath.XPathExpressionException; 
13. import javax.xml.xpath.XPathFactory; 
14.  
15. import org.w3c.dom.Document; 
16. import org.w3c.dom.NodeList; 
17. import org.xml.sax.SAXException; 
18.  
19. public class TestXPath { 
20.  
21.     public static void main(String[] args) { 
22.         read(); 
23.     } 
24.      
25.     public static void read() { 
26.         try { 
27.             DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
28.             DocumentBuilder builder = dbf.newDocumentBuilder(); 
29.             InputStream in = TestXPath.class.getClassLoader().getResourceAsStream("test.xml"); 
30.             Document doc = builder.parse(in); 
31.             XPathFactory factory = XPathFactory.newInstance(); 
32.             XPath xpath = factory.newXPath(); 
33.             // 选取所有class元素的name属性  
34.             // XPath语法介绍： http://w3school.com.cn/xpath/  
35.             XPathExpression expr = xpath.compile("//class/@name"); 
36.             NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET); 
37.             for (int i = 0; i < nodes.getLength(); i++) { 
38.                 System.out.println("name = " + nodes.item(i).getNodeValue()); 
39.                     } 
40.         } catch (XPathExpressionException e) { 
41.             e.printStackTrace(); 
42.         } catch (ParserConfigurationException e) { 
43.             e.printStackTrace(); 
44.         } catch (SAXException e) { 
45.             e.printStackTrace(); 
46.         } catch (IOException e) { 
47.             e.printStackTrace(); 
48.         } 
49.     } 
50.      
51. } 

package test.xml; import java.io.IOException; import java.io.InputStream; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpression; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory; import org.w3c.dom.Document; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; public class TestXPath { public static void main(String[] args) { read(); } public static void read() { try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = dbf.newDocumentBuilder(); InputStream in = TestXPath.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = builder.parse(in); XPathFactory factory = XPathFactory.newInstance(); XPath xpath = factory.newXPath(); // 选取所有class元素的name属性 // XPath语法介绍： http://w3school.com.cn/xpath/ XPathExpression expr = xpath.compile("//class/@name"); NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET); for (int i = 0; i < nodes.getLength(); i++) { System.out.println("name = " + nodes.item(i).getNodeValue()); } } catch (XPathExpressionException e) { e.printStackTrace(); } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } }

六、【补充】

注意4种解析方法对TextNode（文本节点）的处理：

1、在使用DOM时，调用node.getChildNodes()获取该节点的子节点，文本节点也会被当作一个Node来返回，如：

[html] view plaincopyprint?

1. <?xml version="1.0" encoding="UTF-8"?> 
2. <university name="pku"> 
3.     <college name="c1"> 
4.         <class name="class1"> 
5.             <student name="stu1" sex='male' age="21" /> 
6.             <student name="stu2" sex='female' age="20" /> 
7.             <student name="stu3" sex='female' age="20" /> 
8.         </class> 
9.     </college> 
10. </university> 

<?xml version="1.0" encoding="UTF-8"?> <university name="pku"> <college name="c1"> <class name="class1"> <student name="stu1" sex='male' age="21" /> <student name="stu2" sex='female' age="20" /> <student name="stu3" sex='female' age="20" /> </class> </college> </university>

[java] view plaincopyprint?

1. package test.xml; 
2.  
3. import java.io.FileNotFoundException; 
4. import java.io.IOException; 
5. import java.io.InputStream; 
6. import java.util.Arrays; 
7.  
8. import javax.xml.parsers.DocumentBuilder; 
9. import javax.xml.parsers.DocumentBuilderFactory; 
10. import javax.xml.parsers.ParserConfigurationException; 
11.  
12. import org.w3c.dom.Document; 
13. import org.w3c.dom.Element; 
14. import org.w3c.dom.Node; 
15. import org.w3c.dom.NodeList; 
16. import org.xml.sax.SAXException; 
17.  
18. /**
19. * dom读写xml
20. * @author whwang
21. */ 
22. public class TestDom2 { 
23.      
24.     public static void main(String[] args) { 
25.         read(); 
26.     } 
27.      
28.     public static void read() { 
29.         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
30.         try { 
31.             DocumentBuilder builder = dbf.newDocumentBuilder(); 
32.             InputStream in = TestDom2.class.getClassLoader().getResourceAsStream("test.xml"); 
33.             Document doc = builder.parse(in); 
34.             // root <university>  
35.             Element root = doc.getDocumentElement(); 
36.             if (root == null) return; 
37. //          System.err.println(root.getAttribute("name"));  
38.             // all college node  
39.             NodeList collegeNodes = root.getChildNodes(); 
40.             if (collegeNodes == null) return; 
41.             System.err.println("university子节点数：" + collegeNodes.getLength()); 
42.             System.err.println("子节点如下："); 
43.             for(int i = 0; i < collegeNodes.getLength(); i++) { 
44.                 Node college = collegeNodes.item(i); 
45.                 if (college == null) continue; 
46.                 if (college.getNodeType() == Node.ELEMENT_NODE) { 
47.                     System.err.println("\t元素节点：" + college.getNodeName()); 
48.                 } else if (college.getNodeType() == Node.TEXT_NODE) { 
49.                     System.err.println("\t文本节点：" + Arrays.toString(college.getTextContent().getBytes())); 
50.                 } 
51.             } 
52.         } catch (ParserConfigurationException e) { 
53.             e.printStackTrace(); 
54.         } catch (FileNotFoundException e) { 
55.             e.printStackTrace(); 
56.         } catch (SAXException e) { 
57.             e.printStackTrace(); 
58.         } catch (IOException e) { 
59.             e.printStackTrace(); 
60.         } 
61.          
62.     } 
63. } 

package test.xml; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.util.Arrays; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; /** * dom读写xml * @author whwang */ public class TestDom2 { public static void main(String[] args) { read(); } public static void read() { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); try { DocumentBuilder builder = dbf.newDocumentBuilder(); InputStream in = TestDom2.class.getClassLoader().getResourceAsStream("test.xml"); Document doc = builder.parse(in); // root <university> Element root = doc.getDocumentElement(); if (root == null) return; // System.err.println(root.getAttribute("name")); // all college node NodeList collegeNodes = root.getChildNodes(); if (collegeNodes == null) return; System.err.println("university子节点数：" + collegeNodes.getLength()); System.err.println("子节点如下："); for(int i = 0; i < collegeNodes.getLength(); i++) { Node college = collegeNodes.item(i); if (college == null) continue; if (college.getNodeType() == Node.ELEMENT_NODE) { System.err.println("\t元素节点：" + college.getNodeName()); } else if (college.getNodeType() == Node.TEXT_NODE) { System.err.println("\t文本节点：" + Arrays.toString(college.getTextContent().getBytes())); } } } catch (ParserConfigurationException e) { e.printStackTrace(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (SAXException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } 输出的结果是：

[java] view plaincopyprint?

1. university子节点数：3 
2. 子节点如下： 
3.     文本节点：[10, 9] 
4.     元素节点：college 
5.     文本节点：[10] 

university子节点数：3 子节点如下： 文本节点：[10, 9] 元素节点：college 文本节点：[10]

其中\n的ASCII码为10，\t的ASCII码为9。结果让人大吃一惊，university的子节点数不是1，也不是2，而是3，这3个子节点都是谁呢？为了看得更清楚点，把xml文档改为：

[html] view plaincopyprint?

1. <?xml version="1.0" encoding="UTF-8"?> 
2. <university name="pku">11 
3.     <college name="c1"> 
4.         <class name="class1"> 
5.             <student name="stu1" sex='male' age="21" /> 
6.             <student name="stu2" sex='female' age="20" /> 
7.             <student name="stu3" sex='female' age="20" /> 
8.         </class> 
9.     </college>22 
10. </university> 

<?xml version="1.0" encoding="UTF-8"?> <university name="pku">11 <college name="c1"> <class name="class1"> <student name="stu1" sex='male' age="21" /> <student name="stu2" sex='female' age="20" /> <student name="stu3" sex='female' age="20" /> </class> </college>22 </university>还是上面的程序，输出结果为：

[java] view plaincopyprint?

1. university子节点数：3 
2. 子节点如下： 
3.     文本节点：[49, 49, 10, 9] 
4.     元素节点：college 
5.     文本节点：[50, 50, 10] 

university子节点数：3 子节点如下： 文本节点：[49, 49, 10, 9] 元素节点：college 文本节点：[50, 50, 10]其中数字1的ASCII码为49，数字2的ASCII码为50。

2、使用SAX来解析同DOM，当你重写它的public void characters(char[] ch, int start, int length)方法时，你就能看到。

3、JDOM，调用node.getChildren()只返回子节点，不包括TextNode节点（不管该节点是否有Text信息）。如果要获取该节点的Text信息，可以调用node.getText()方法，该方法返回节点的Text信息，也包括\n\t等特殊字符。

4、DOM4j同JDOM

参考：

http://www.docin.com/p-78963650.html

http://wenku.baidu.com/view/b091f9360b4c2e3f5727638b.html

http://kree.iteye.com/blog/668280