一 xml文件内容
<?xml version="1.0" encoding="UTF-8"?> <books> <book id="12"> <name>book1</name> <price>85.5</price> </book> <book id="15"> <name>book2</name> <price>39.0</price> </book> </books>
二 类Book的定义
public class Book { private int id; private String name; private float price; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public float getPrice() { return price; } public void setPrice(float price) { this.price = price; } @Override public String toString(){ return this.id+":"+this.name+":"+this.price; } }
三 解析服务编写
import java.io.InputStream; import java.util.ArrayList; import java.util.List;
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 SaxParseService extends DefaultHandler{ private List<Book> books = null; private Book book = null; private String preTag = null;//作用是记录解析时的上一个节点名称 public List<Book> getBooks(InputStream xmlStream) throws Exception{ SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser parser = factory.newSAXParser(); SaxParseService handler = new SaxParseService(); parser.parse(xmlStream,handler); return handler.getBooks(); } public List<Book> getBooks(){ return books; } @Override public void startDocument() throws SAXException { books = new ArrayList<Book>(); }
@Override public void startElement(String uri,String localName,String qName,Attributes attributes) throws SAXException { if("book".equals(qName)){ book = new Book(); book.setId(Integer.parseInt(attributes.getValue(0))); } preTag = qName;//将正在解析的节点名称赋给preTag }
@Override public void endElement(String uri,String qName) throws SAXException { if("book".equals(qName)){ books.add(book); book = null; } preTag = null;
/**当解析结束时置为空。这里很重要,例如,当图中画3的位置结束后,会调用这个方法 ,如果这里不把preTag置为null,根据startElement(....)方法,preTag的值还是book,当文档顺序读到图 中标记4的位置时,会执行characters(char[] ch,int start,int length)这个方法,而characters(....)方 法判断preTag!=null,会执行if判断的代码,这样就会把空值赋值给book,这不是我们想要的。*/ } @Override public void characters(char[] ch,int length) throws SAXException { if(preTag!=null){ String content = new String(ch,start,length); if("name".equals(preTag)){ book.setName(content); }else if("price".equals(preTag)){ book.setPrice(Float.parseFloat(content)); } } } }
四 解析xml
import java.io.InputStream; import java.util.List;
import junit.framework.TestCase; public class ParseTest extends TestCase{ public void testSAX() throws Throwable{ SaxParseService sax = new SaxParseService(); InputStream input = this.getClass().getClassLoader().getResourceAsStream("com/xml/book.xml"); List<Book> books = sax.getBooks(input); for(Book book : books){ System.out.println(book.toString()); } } } (编辑:李大同)
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