JAVA SE 读写XML——SAX

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;
    }
}

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JAVA SE 读写XML——SAX

SAX

SAXParser类

SAXParserFactory类

DefaultHandler类

实例应用

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