SAX
通过创建Handler逐步解析
主要用的类
- SAXParserFactory
- SAXParser
- DefaultHanderler
SAXParser类
定义包装 XMLReader 实现类的 API
构造方法
- SAXParser() //将阻止实例化的受保护构造方法
- abstract Parser getParser() //返回由此类的实现封装的 SAX 解析器
- abstract XMLReader getXMLReader() //返回由此类的实现封装的 XMLReader
- void parse(File f, DefaultHandler dh) //使用指定的 DefaultHandler 将指定文件的内容解析为 XML
- void parse(File f, HandlerBase hb) //使用指定的 HandlerBase 将指定文件的内容解析为 XML
SAXParserFactory类
构造方法
- SAXParserFactory() //受保护构造方法,以强制使用 newInstance()
常用方法
- SAXParserFactory newInstance() //获取 SAXParserFactory 的一个新实例
- SAXParser newSAXParser() //使用当前配置的工厂参数创建 SAXParser 的一个新实例
- void setNamespaceAware(boolean awareness) //指定由此代码生成的解析器将提供对 XML 名称空间的支持
DefaultHandler类
SAX2 事件处理程序的默认基类
构造方法
- DefaultHandler()
常用方法
- void characters(char[] ch, int start, int length) //接收元素中字符数据的通知
- void endDocument() //接收文档结束的通知
- void endElement(String uri, String localName, String qName) //接收元素结束的通知。
- void ignorableWhitespace(char[] ch, int start, int length) //接收元素内容中可忽略空白的通知
- void notationDecl(String name, String publicId, String systemId) //接收注释声明的通知
- void processingInstruction(String target, String data) //接收处理指令的通知。
- InputSource resolveEntity(String publicId, String systemId) //解析外部实体。
- void setDocumentLocator(Locator locator) //接收文档事件的 Locator 对象。
- void skippedEntity(String name) //接收跳过的实体的通知。
- void startDocument() //接收文档开始的通知。
- void startElement(String uri, String localName, String qName, Attributes attributes) //接收元素开始的通知。
- void startPrefixMapping(String prefix, String uri) //接收名称空间映射开始的通知。
- void unparsedEntityDecl(String name, String publicId, String systemId, String notationName) //接收未解析实体声明的通知。
- void warning(SAXParseException e) //接收解析器警告的通知
实例应用
//测试类
package TESTXML;
import JDom.Book;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
public class TestSax {
public static void main(String[] args) {
TestSax testSax = new TestSax();
testSax.createXml();
}
//解析xml
public ArrayList<Book> parseXML() {
SAXParserFactory factory = SAXParserFactory.newInstance();
TestHandler handler = null;
try {
SAXParser parser = factory.newSAXParser();
handler = new TestHandler();//创建处理器
parser.parse("books.xml", handler);//解析xml
System.out.println("一共有" + handler.getBookList().size()
+ "本书");
for (Book book : handler.getBookList()) {
System.out.println("id:" + book.getId());
System.out.println("书名:" + book.getName());
System.out.println("作者:" + book.getAuthor());
System.out.println("年份:" + book.getYear());
System.out.println("价格" + book.getPrice());
System.out.println("————————————end——————————");
}
} catch (ParserConfigurationException | SAXException | IOException e) {
e.printStackTrace();
}
return handler.getBookList();
}
//生成xml
public void createXml() {
ArrayList<Book> bookList = parseXML();
SAXTransformerFactory tff = (SAXTransformerFactory) SAXTransformerFactory.newInstance();
try {
TransformerHandler handler = tff.newTransformerHandler();
Transformer transformer = handler.getTransformer();
transformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
File file = new File("newbook.xml");
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
Result result = new StreamResult(new FileOutputStream(file));
handler.setResult(result);
handler.startDocument();
AttributesImpl attributes = new AttributesImpl();
handler.startElement("", "", "bookstore", attributes);
for (Book book : bookList) {
attributes.clear();
attributes.addAttribute("", "", "id", "", book.getId());
handler.startElement("", "", "book", attributes);
if (book.getName() != null && !book.getName().trim().equals("")) {
attributes.clear();
handler.startElement("", "", "name", attributes);
handler.characters(book.getName().toCharArray(), 0, book.getName().length());
handler.endElement("", "", "name");
}
if (book.getYear() != null && !book.getYear().trim().equals("")) {
attributes.clear();
handler.startElement("", "", "year", attributes);
handler.characters(book.getYear().toCharArray(), 0, book.getYear().length());
handler.endElement("", "", "year");
}
if (book.getAuthor() != null && !book.getAuthor().trim().equals("")) {
attributes.clear();
handler.startElement("", "", "author", attributes);
handler.characters(book.getAuthor().toCharArray(), 0, book.getAuthor().length());
handler.endElement("", "", "author");
}
if (book.getPrice() != null && !book.getPrice().trim().equals("")) {
attributes.clear();
handler.startElement("", "", "price", attributes);
handler.characters(book.getPrice().toCharArray(), 0, book.getPrice().length());
handler.endElement("", "", "price");
}
handler.endElement("", "", "book");
}
handler.endElement("", "", "bookstore");
handler.endDocument();
} catch (TransformerConfigurationException | FileNotFoundException | SAXException e) {
e.printStackTrace();
}
}
}
//处理器类
package TESTXML;
import JDom.Book;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import java.util.ArrayList;
public class TestHandler extends DefaultHandler {
String value = null;
Book book = null;
int bookIndex = 0;
private ArrayList<Book> bookList = new ArrayList<Book>();
public ArrayList<Book> getBookList() {
return bookList;
}
@Override
public void startDocument() throws SAXException {
super.startDocument();
}
@Override
public void endDocument() throws SAXException {
super.endDocument();
}
@Override
public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
super.startElement(uri, localName, qName, attributes);
if (qName.equals("book")) {
bookIndex++;
book = new Book();
int num = attributes.getLength();
for (int i = 0; i < num; i++) {
if (attributes.getQName(i).equals("id")) {
book.setId(attributes.getValue(i));//赋值
}
}
}
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
super.endElement(uri, localName, qName);
if (qName.equals("book")) {//判断是否针对一本书已经遍历结束
bookList.add(book);
book = null;
} else if (qName.equals("name")) {
book.setName(value);
} else if (qName.equals("author")) {
book.setAuthor(value);
} else if (qName.equals("year")) {
book.setYear(value);
} else if (qName.equals("price")) {
book.setPrice(value);
}
}
@Override
public void characters(char[] ch, int start, int length) throws SAXException {
super.characters(ch, start, length);
value = new String(ch, start, length);
}
}
//存放数据的对象
public class Book {
private String id;
private String name;
private String author;
private String year;
private String price;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public String getYear() {
return year;
}
public void setYear(String year) {
this.year = year;
}
public String getPrice() {
return price;
}
public void setPrice(String price) {
this.price = price;
}
}
相关文章——读写xml系列方式