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(" "换行+制表符)

　　<book>Text文本节点(" "换行+2个制表符)

　　　　<name>Text文本节点("Thinking in JAVA")</name>Text文本节点(" "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("
" + this.toBlankString(this.frontBlankCount) 
                + ">>> start prefix_mapping : xmlns:" + prefix + "="" + uri + """);
    }

    @Override
    public void endPrefixMapping(String prefix) throws SAXException {
        System.out.print("
" + 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 '
': buffer.append("\r");break;
                case '
': buffer.append("\n");break;
                case '	': buffer.append("\t");break;
                case '"': buffer.append("\"");break;
                default: buffer.append(ch[i]);
            }
        }
        System.out.println("	>>> 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 '
': buffer.append("\r");break;
                case '
': buffer.append("\n");break;
                case '	': 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):
　　>>> start element : bk:book(http://test.org/books) >>> characters(3):
　　　　>>> start element : bk:name(http://test.org/books) >>> characters(16): Thinking in JAVA
　　　　>>> end element : bk:name(http://test.org/books) >>> characters(2):
　　>>> end element : bk:book(http://test.org/books) >>> characters(2):
　　>>> start element : bk:book(http://test.org/books) >>> characters(3):
　　　　>>> start element : bk:name(http://test.org/books) >>> characters(10): Core JAVA2
　　　　>>> end element : bk:name(http://test.org/books) >>> characters(2):
　　>>> end element : bk:book(http://test.org/books) >>> characters(2):
　　>>> start element : bk:book(http://test.org/books) >>> characters(3):
　　　　>>> start element : bk:name(http://test.org/books) >>> characters(10): C++ primer
　　　　>>> end element : bk:name(http://test.org/books) >>> characters(3):

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