SAX解析xml (遍历DOM树各节点)

本文参考 http://yangjunfeng.iteye.com/blog/401377

1. books.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <bk:books count="3" xmlns:bk="http://test.org/books">
     <!--books's comment -->
     <bk:book id="1">
         <bk:name>Thinking in JAVA</bk:name>
     </bk:book>
     <bk:book id="2">
         <bk:name>Core JAVA2</bk:name>
     </bk:book>
     <bk:book id="3">
         <bk:name>C++ primer</bk:name>
         <addr:address xmlns:addr="http://test.org/address">
             <addr:state>China</addr:state>
             <addr:city>ShangHai</addr:city>
         </addr:address>
     </bk:book>
 </bk:books> 

xml文件基本结构：

<books>Text文本节点("\n\t"换行+制表符)

　　<book>Text文本节点("\n\t\t"换行+2个制表符)

　　　　<name>Text文本节点("Thinking in JAVA")</name>Text文本节点("\n\t"换行+制表符)

　　</book>

.......

.......

</books>

2. 使用SAX api 解析xml

 package sax.parsing.example;

 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.Reader;

 import org.testng.annotations.Test;
 import org.xml.sax.Attributes;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.InputSource;
 import org.xml.sax.Locator;
 import org.xml.sax.SAXException;
 import org.xml.sax.XMLReader;
 import org.xml.sax.helpers.XMLReaderFactory;

 import bsh.This;

 class MyContentHandler implements ContentHandler {

     private StringBuffer stringBuffer;
     int frontBlankCount = 0;

     public String toBlankString(int count) {
         StringBuffer buffer = new StringBuffer();
         for (int i=0; i<count; i++)
             buffer.append("    ");
         return buffer.toString();
     }

     @Override
     public void setDocumentLocator(Locator locator) {
         System.out.println(this.toBlankString(this.frontBlankCount)
                 + ">>> set document_locator : (lineNumber = " + locator.getLineNumber()
                 + ", columnNumber = " + locator.getColumnNumber()
                 + ", systemId = " + locator.getSystemId()
                 + ". publicId = " + locator.getPublicId()
                 + ")"
                 );
     }

     @Override
     public void startDocument() throws SAXException {
         System.out.println(this.toBlankString(frontBlankCount) + ">>> start document");
     }

     @Override
     public void endDocument() throws SAXException {
         System.out.print(this.toBlankString(frontBlankCount) + ">>> end document");
     }

     @Override
     public void startPrefixMapping(String prefix, String uri) throws SAXException {
         System.out.println("\n" + this.toBlankString(this.frontBlankCount)
                 + ">>> start prefix_mapping : xmlns:" + prefix + "=\"" + uri + "\"");
     }

     @Override
     public void endPrefixMapping(String prefix) throws SAXException {
         System.out.print("\n" + this.toBlankString(this.frontBlankCount) + ">>> end prefix_mapping : " + prefix);
     }

     @Override
     public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
         System.out.print(this.toBlankString(this.frontBlankCount++) + ">>> start element : "
                     + qName + "(" + uri + ")"
                     );
     }

     @Override
     public void endElement(String uri, String localName, String qName) throws SAXException {
         System.out.print(this.toBlankString(--this.frontBlankCount) + ">>> end element : "
                 + qName + "(" + uri + ")"
                 );
     }

     /**
      *  Text文本节点 处理
      */
     @Override
     public void characters(char[] ch, int start, int length) throws SAXException {

         StringBuffer buffer = new StringBuffer();

         for (int i=start; i<start+length; i++) {
             switch (ch[i]) {
                 case '\\': buffer.append("\\\\");break;
                 case '\r': buffer.append("\\r");break;
                 case '\n': buffer.append("\\n");break;
                 case '\t': buffer.append("\\t");break;
                 case '\"': buffer.append("\\\"");break;
                 default: buffer.append(ch[i]);
             }
         }
         System.out.println("\t>>> characters(" + length + "): " + buffer.toString());
     }

     @Override
     public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {

         StringBuffer buffer = new StringBuffer();

         for (int i=start; i<start+length; i++) {
             switch (ch[i]) {
                 case '\\': buffer.append("\\\\");break;
                 case '\r': buffer.append("\\r");break;
                 case '\n': buffer.append("\\n");break;
                 case '\t': buffer.append("\\t");break;
                 case '\"': buffer.append("\\\"");break;
                 default: buffer.append(ch[i]);
             }
         }
         System.out.print(this.toBlankString(frontBlankCount)
                 + ">>> ignorable whitespace(" + length + "): " + buffer.toString());
     }

     @Override
     public void processingInstruction(String target, String data) throws SAXException {
         System.out.print(this.toBlankString(this.frontBlankCount)
                 + ">>> process instruction : (target = \"" + target + "\", data = \"" + data + ")");

     }

     @Override
     public void skippedEntity(String name) throws SAXException {
         System.out.print(this.toBlankString(this.frontBlankCount) + ">>> skipped_entity : " + name);
     }
 }

 public class SaxTest {

     @Test
     public void test() throws SAXException, FileNotFoundException, IOException {

         XMLReader reader = XMLReaderFactory.createXMLReader();
         reader.setFeature("http://xml.org/sax/features/validation", true);
         reader.setFeature("http://xml.org/sax/features/namespaces", true);
         reader.setContentHandler(new MyContentHandler());
         reader.parse(new InputSource(new FileInputStream("src/sax/parsing/example/books.xml")));

     }
 }

输出结果：

>>> set document_locator : (lineNumber = 1, columnNumber = 1, systemId = null. publicId = null)
>>> start document
[Error] :5:10: Document is invalid: no grammar found.
[Error] :5:10: Document root element "bk:books", must match DOCTYPE root "null".

>>> start prefix_mapping : xmlns:bk="http://test.org/books"
>>> start element : bk:books(http://test.org/books) >>> characters(2): \n\t
　　>>> start element : bk:book(http://test.org/books) >>> characters(3): \n\t\t
　　　　>>> start element : bk:name(http://test.org/books) >>> characters(16): Thinking in JAVA
　　　　>>> end element : bk:name(http://test.org/books) >>> characters(2): \n\t
　　>>> end element : bk:book(http://test.org/books) >>> characters(2): \n\t
　　>>> start element : bk:book(http://test.org/books) >>> characters(3): \n\t\t
　　　　>>> start element : bk:name(http://test.org/books) >>> characters(10): Core JAVA2
　　　　>>> end element : bk:name(http://test.org/books) >>> characters(2): \n\t
　　>>> end element : bk:book(http://test.org/books) >>> characters(2): \n\t
　　>>> start element : bk:book(http://test.org/books) >>> characters(3): \n\t\t
　　　　>>> start element : bk:name(http://test.org/books) >>> characters(10): C++ primer
　　　　>>> end element : bk:name(http://test.org/books) >>> characters(3): \n\t\t

　　　　>>> start prefix_mapping : xmlns:addr="http://test.org/address"
　　　　>>> start element : addr:address(http://test.org/address) >>> characters(4): \n\t\t\t
　　　　　　>>> start element : addr:state(http://test.org/address) >>> characters(5): China
　　　　　　>>> end element : addr:state(http://test.org/address) >>> characters(4): \n\t\t\t
　　　　　　>>> start element : addr:city(http://test.org/address) >>> characters(8): ShangHai
　　　　　　>>> end element : addr:city(http://test.org/address) >>> characters(3): \n\t\t
　　　　>>> end element : addr:address(http://test.org/address)
　　　　>>> end prefix_mapping : addr >>> characters(2): \n\t
　　>>> end element : bk:book(http://test.org/books) >>> characters(1): \n
>>> end element : bk:books(http://test.org/books)
>>> end prefix_mapping : bk>>> end document