XML的JAVA 解析(一)(6a)

王朝java/jsp·作者佚名  2006-01-08
窄屏简体版  字體: |||超大  

下列代码说明这种ContentHandler轮换技术。Contents缓存被类Example6和其它特定ContentHandler内部类共享:

import org.xml.sax.*;

import org.xml.sax.helpers.*;

import java.io.*;

import java.util.*;

import common.*;

public class Example6 extends DefaultHandler {

// XML解析...

XMLReader parser;

// 被解析对象...

Example6Circle circleMapper = new Example6Circle();

Example6Square squareMapper = new Example6Square();

Example6Triangle triangleMapper = new Example6Triangle();

// 不同形体的本地向量表...

private Vector circles = new Vector();

private Vector triangles = new Vector();

private Vector squares = new Vector();

// 从"characters" SAX事件中收集数据的缓存。

private CharArrayWriter contents = new CharArrayWriter();

// 用XML解析器为参数的构造函数...

Example6( XMLReader parser ) {

this.parser = parser;

}

// 重载DefaultHandler类以拦截SAX事件的方法。

//

// 头于所有有效事件的详细内容,参见org.xml.sax.ContentHandler。

//

public void startElement( String namespaceURI,

String localName,

String qName,

Attributes attr ) throws SAXException {

contents.reset();

if ( localName.equals( "Circle" ) ) {

Circle aCircle = new Circle();

aCircle.name = attr.getValue( "name" );

circles.addElement( aCircle );

circleMapper.collectCircle( parser, this, aCircle );

}

if ( localName.equals( "Square" ) ) {

Square aSquare = new Square();

aSquare.name = attr.getValue( "name" );

squares.addElement( aSquare );

squareMapper.collectSquare( parser, this, aSquare );

}

if ( localName.equals( "Triangle" ) ) {

Triangle aTriangle = new Triangle();

aTriangle.name = attr.getValue( "name" );

triangles.addElement( aTriangle );

triangleMapper.collectTriangle( parser, this, aTriangle);

}

}

public void endElement( String namespaceURI,

String localName,

String qName ) throws SAXException {

// endElement SAX事件中已经没有需要Example 6映射器处理的了。

}

public void characters( char[] ch, int start, int length )

throws SAXException {

// // 将数据内容写入缓存。

contents.write( ch, start, length );

}

public Vector getCircles() {

return circles;

}

public Vector getSquares() {

return squares;

}

public Vector getTriangles() {

return triangles;

}

public static void main( String[] argv ){

System.out.println( "Example6:" );

try {

// 创建SAX 2解析器...

XMLReader xr = XMLReaderFactory.createXMLReader();

// 安装ContentHandler...

Example6 ex6 = new Example6(xr);

xr.setContentHandler( ex6 );

// 解析文件...

xr.parse( new InputSource(

new FileReader( "Example6.xml" )) );

//将圆形对象显示到标准输出...

Circle c;

Vector items = ex6.getCircles();

Enumeration e = items.elements();

while( e.hasMoreElements()){

c = (Circle) e.nextElement();

c.print( System.out );

}

// // 将长方形对象显示到标准输出...

Square s;

items = ex6.getSquares();

e = items.elements();

while( e.hasMoreElements()){

s = (Square) e.nextElement();

s.print( System.out );

}

// 将三角形对象显示到标准输出...

Triangle t;

items = ex6.getTriangles();

e = items.elements();

while( e.hasMoreElements()){

t = (Triangle) e.nextElement();

t.print( System.out );

}

}catch ( Exception e ) {

e.printStackTrace();

}

}

}

(未完待续)

 
 
 
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