[java开发篇][dom模块] 遍历解析xml

2022-12-03 18:48:35

http://blog.csdn.net/andie_guo/article/details/24844351

XML DOM节点树

XML DOM将XML文档作为树结构，树结构称为一个节点树。所有的节点可以通过树访问，它们的内容可以被修改或删除，也可以建立新的元素。节点树用于显示节点集和它们之间的联系。下图呈现的是books.XML文件的节点树。

常用的几个对象：

1）Element类：

是Node类最主要的子对象，被广泛使用，在元素中可以包含属性，因而Element中有存取其属性的方法。

2）Node类：

Node对象是DOM中最基本的对象，代表了文档树中的抽象节点。但在实际使用中很少会直接使用Node对象，而是使用Node对象的子对象Element,Attr,Text等。

3）NodeList类：

代表了一个包含一个或者多个Node的列表，根据操作可以将其简化的看做为数组。

DOM XML Parser 解析XML文件

<?xml version="1.0" encoding="UTF-8"?>

<!-- Edited by XMLSpy -->

<bookstore>

    <book category="cooking">

        <title lang="en">Everyday Italian</title>

        <author>Giada De Laurentiis</author>

        <year>2005</year>

        <price>30.00</price>

    </book>

    <book category="children">

        <title lang="en">Harry Potter</title>

        <author>J K. Rowling</author>

        <year>2005</year>

        <price>29.99</price>

    </book>

    <book category="web">

        <title lang="en">XQuery Kick Start</title>

        <author>James McGovern</author>

        <author>Per Bothner</author>

        <author>Kurt Cagle</author>

        <author>James Linn</author>

        <author>Vaidyanathan Nagarajan</author>

        <year>2003</year>

        <price>49.99</price>

    </book>

    <book category="web" cover="paperback">

        <title lang="en">Learning XML</title>

        <author>Erik T. Ray</author>

        <year>2003</year>

        <price>39.95</price>

    </book>

</bookstore>

Book.java：该对象是一个实体Bean，其字段信息对应着xml文件里的元素字段，由于篇幅有限，读者自行生成get、set方法。

package com.andieguo.xmldemo;  

public class Book {

    private String category;

    private String titleLang;

    private String title;

    private String author;

    private Integer year;

    private Double price;  

    @Override

    public String toString() {

        return "Book [category=" + category + ", titleLang=" + titleLang + ", title=" + title + ", author=" + author + ", year=" + year + ", price=" + price + "]";

    }

    //生成字段的get、set方法

}

ReadXMLFile.java ：解析XML文件并存入List<Book>集合。

package com.andieguo.xmldemo;  

import java.io.File;

import java.util.ArrayList;

import java.util.List;  

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;  

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;  

public class ReadXMLFile {  

    public static void main(String[] args) {

        File file = new File("src/com/andieguo/xmldemo/books.xml");//books.xml文件应放在和ReadXMLFile.java同级的文件夹下

        List<Book> books = readXMLFile(file);

        for (Book book : books) {

            System.out.println(book.toString());

        }

    }  

    public static List<Book> readXMLFile(File file) {

        List<Book> lists = new ArrayList<Book>();

        try {  

            DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();

            DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();

            Document doc = dBuilder.parse(file);

            NodeList bookList = doc.getElementsByTagName("book");

            for (int i = 0; i < bookList.getLength(); i++) {

                Node bookNode = bookList.item(i);

                if (bookNode.getNodeType() == Node.ELEMENT_NODE) {

                    Element bookElement = (Element) bookNode;

                    Book book = new Book();

                    book.setCategory(bookElement.getAttribute("category"));

                    Element titleElement = (Element) bookElement.getElementsByTagName("title").item(0);

                    book.setTitle(titleElement.getTextContent());

                    book.setTitleLang(titleElement.getAttribute("lang"));

                    NodeList authorList = bookElement.getElementsByTagName("author");

                    String author = "";

                    for (int j = 0; j < authorList.getLength(); j++) {

                        author = author + authorList.item(j).getTextContent() + "/";

                    }

                    author = author.substring(0, author.length() - 1);

                    book.setAuthor(author);

                    book.setYear(Integer.valueOf(bookElement.getElementsByTagName("year").item(0).getTextContent()));

                    book.setPrice(Double.valueOf(bookElement.getElementsByTagName("price").item(0).getTextContent()));

                    lists.add(book);

                }  

            }

        } catch (Exception e) {

            e.printStackTrace();

        }

        return lists;

    }

}

运行结果如图所示：

package com.andieguo.xmldemo;
import java.io.File;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class ReadXMLFile {
public static void main(String[] args) {
File file = new File("src/com/andieguo/xmldemo/books.xml");//books.xml文件应放在和ReadXMLFile.java同级的文件夹下
List<Book> books = readXMLFile(file);
for (Book book : books) {
System.out.println(book.toString());
}
}
public static List<Book> readXMLFile(File file) {
List<Book> lists = new ArrayList<Book>();
try {
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(file);
NodeList bookList = doc.getElementsByTagName("book");
for (int i = 0; i < bookList.getLength(); i++) {
Node bookNode = bookList.item(i);
if (bookNode.getNodeType() == Node.ELEMENT_NODE) {
Element bookElement = (Element) bookNode;
Book book = new Book();
book.setCategory(bookElement.getAttribute("category"));
Element titleElement = (Element) bookElement.getElementsByTagName("title").item(0);
book.setTitle(titleElement.getTextContent());
book.setTitleLang(titleElement.getAttribute("lang"));
NodeList authorList = bookElement.getElementsByTagName("author");
String author = "";
for (int j = 0; j < authorList.getLength(); j++) {
author = author + authorList.item(j).getTextContent() + "/";
}
author = author.substring(0, author.length() - 1);
book.setAuthor(author);
book.setYear(Integer.valueOf(bookElement.getElementsByTagName("year").item(0).getTextContent()));
book.setPrice(Double.valueOf(bookElement.getElementsByTagName("price").item(0).getTextContent()));
lists.add(book);
}
}
} catch (Exception e) {
e.printStackTrace();
}
return lists;
}
}

码农公寓

XML DOM节点树

DOM XML Parser 解析XML文件

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