SAX对xml文件的解析

Posted 2020-10-12 塑料味的美年达

package com.fortune;

import org.xml.sax.SAXException;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class SaxParser implements xmlParse{
    @Override
    public List<Book> parseXml(String fileName) throws IOException, SAXException, ParserConfigurationException {
        List<Book> list = new ArrayList<Book>();
        SAXParserFactory factory = SAXParserFactory.newInstance();//解析器工厂实例
        MySaxHandler handler = null;
        SAXParser parser = factory.newSAXParser();
        InputStream inputStream = new FileInputStream(fileName);
        handler = new MySaxHandler();
        parser.parse(inputStream,handler);
        list = handler.getBookList();
        return list;
    }

    public static void main(String[] args) throws IOException, SAXException, ParserConfigurationException {
        xmlParse parse = new SaxParser();
        List<Book> list = parse.parseXml("E:\\Alive\\project\\src\\com\\fortune\\book.xml");
        System.out.println("SAX 解析结果:");
        for (Book book : list){
            System.out.println(book);
        }
    }
}

package com.fortune;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import java.util.ArrayList;
import java.util.List;

/**
 * 事件处理器
 */
public class MySaxHandler extends DefaultHandler {
    private String tag;
    private Book book;
    private List<Book> bookList;

    public List<Book> getBookList() {
        return bookList;
    }

    //文档读取开始
    public void startDocument() throws SAXException {
        super.startDocument();
        bookList = new ArrayList<Book>();

    }

    //文档读取结束
    public void endDocument() throws SAXException {
        super.endDocument();

    }

    //元素读取开始
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        super.startElement(uri, localName, qName, attributes);
        if(qName.equals("book")){
            book = new Book();
            String bookNo = attributes.getValue("bookno");
            book.setBookNo(bookNo);
        }
        tag = qName;
    }


    //元素读取结束
    public void endElement(String uri, String localName, String qName) throws SAXException {
        super.endElement(uri, localName, qName);
        if(qName.equals("book")){//如果读到结尾，证明元素都已经读取完毕
            bookList.add(book);
            book = null;//初始化，为下一本书
        }
        tag = null;
    }


    //character内容读取
    public void characters(char[] ch, int start, int length) throws SAXException {
        super.characters(ch, start, length);
        if(tag!=null){//读取到所需的信息
            String string = new String(ch,start,length).trim();//从头到尾读取完，ch应该是内容数组
            if(tag.equals("title")){
                book.setTitle(string);
            }
            if(tag.equals("author")){
                book.setAuthor(string);
            }
            if(tag.equals("price")){
                book.setPrice(Double.parseDouble(string));
            }
        }
    }

}

package com.fortune;

import org.xml.sax.SAXException;

import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.util.List;

public interface xmlParse {
    public List<Book> parseXml(String fileName) throws IOException, SAXException, ParserConfigurationException;

}

package com.fortune;

public class Book {
    private String bookNo;
    private String title;
    private String author;
    private double price;

    public Book() {
    }

    public Book(String bookNo, String title, String author, double price) {
        this.bookNo = bookNo;
        this.title = title;
        this.author = author;
        this.price = price;
    }

    public String getBookNo() {
        return bookNo;
    }

    public void setBookNo(String bookNo) {
        this.bookNo = bookNo;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public double getPrice() {
        return price;
    }

    public void setPrice(double price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "Book{" +
                "bookNo=‘" + bookNo + ‘\‘‘ +
                ", title=‘" + title + ‘\‘‘ +
                ", author=‘" + author + ‘\‘‘ +
                ", price=" + price +
                ‘}‘;
    }
}

xml文件

<?xml version="1.0" encoding="utf-8" ?>
<books>
    <book bookno="001">
        <title>java编程</title>
        <author>张三</author>
        <price>80</price>
    </book>
    <book bookno="002">
        <title>安卓开发</title>
        <author>李四</author>
        <price>100</price>
    </book>
</books>