DOM

org.w3c.dom为文档对象模型 (DOM) 提供接口，该模型是 Java API for XML Processing 的组件 API。

生成xml文件示例

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

public class DOM4Jsettest {
    public static void main(String[] args) throws IOException {
        Document document = DocumentHelper.createDocument();
        Element bookstore = document.addElement("bookstore");
        Element book1 = bookstore.addElement("book");
        book1.addAttribute("id", "book1");
        book1.addAttribute("other", "这是第二本书");
        Element Name = book1.addElement("Name");
        Element Author = book1.addElement("Author");
        Element Type = book1.addElement("Type");
        Element Price = book1.addElement("Price");
        Author.addText("天哥哥");
        Name.addText("Get Me Fly");
        Price.addText("999RMB");
        Type.addText("励志");
        OutputFormat outputFormat = OutputFormat.createPrettyPrint();
        outputFormat.setEncoding("UTF-8");
        outputFormat.setIndentSize(4);
        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(new File(
        "BookstorebyDOM4J.xml")), outputFormat);
        xmlWriter.write(document);
        xmlWriter.close();
    }
}

解析xml文件示例

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class DOMtest {
static int bookindex;
static Book onebook = null;
static List<Book> booklist = new ArrayList<Book>();

public static void main(String[] args) throws ParserConfigurationException,
        SAXException, IOException {
    DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory
            .newInstance();
    DocumentBuilder documentBuilder = documentBuilderFactory
            .newDocumentBuilder();
    Document document = documentBuilder.parse("Bookstore.xml");
    Node bookstore = document.getChildNodes().item(0);

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

        NodeList books = bookstore.getChildNodes();
        for (int j = 0; j < books.getLength(); j++) {
            onebook = new Book();
            Node book = books.item(j);

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

                NamedNodeMap bookattributes = book.getAttributes();
                for (int i = 0; i < bookattributes.getLength(); i++) {
                    Node attribute = bookattributes.item(i);
                    if (attribute.getNodeType() == Node.ATTRIBUTE_NODE) {

                        if (attribute.getNodeName() == "id") {
                            onebook.setId(attribute.getNodeValue());
                        }
                        if (attribute.getNodeName() == "other") {
                            onebook.setOther(attribute.getNodeValue());
                        }
                    }
                }
                NodeList bookchilds = book.getChildNodes();
                for (int k = 0; k < bookchilds.getLength(); k++) {
                    Node bookchild = bookchilds.item(k);
                    if (bookchild.getNodeName() == "Name") {
                        onebook.setName(bookchild.getTextContent());
                    }
                    if (bookchild.getNodeName() == "Price") {
                        onebook.setPrice(bookchild.getTextContent());
                    }
                    if (bookchild.getNodeName() == "Type") {
                        onebook.setType(bookchild.getTextContent());
                    }
                    if (bookchild.getNodeName() == "Author") {
                        onebook.setAuthor(bookchild.getTextContent());
                    }
                }
                booklist.add(onebook);
            }
        }
    }
    for (Book book : booklist) {
        System.out.println("=====存放入list然后输出第" + (++bookindex)
                + "本书信息=====");
        System.out.println("该书编号：" + book.getId());
        System.out.println("该书名字：" + book.getName());
        System.out.println("该书作者：" + book.getAuthor());
        System.out.println("该书价格：" + book.getPrice());
        System.out.println("该书类型：" + book.getType());
        System.out.println("该书信息：" + book.getOther());
    }
}

JDOM

JDOM的目的是成为 Java 特定文档模型，它简化与 XML 的交互并且比使用 DOM 实现更快。由于是第一个 Java 特定模型，JDOM 一直得到大力推广和促进。正在考虑通过“Java 规范请求 JSR-102”将它最终用作“Java 标准扩展”。

JDOM 文档声明其目的是“使用 20%（或更少）的精力解决 80%（或更多）Java/XML 问题”（根据学习曲线假定为 20%）。JDOM 对于大多数 Java/XML 应用程序来说当然是有用的，并且大多数开发者发现 API 比 DOM4J 容易理解得多。JDOM 还包括对程序行为的相当广泛检查以防止用户做任何在 XML 中无意义的事。然而，它仍需要您充分理解 XML 以便做一些超出基本的工作（或者甚至理解某些情况下的错误）。这也许是比学习 DOM4J 或 JDOM 接口都更有意义的工作。 JDOM 自身不包含解析器。它通常使用 SAX2 解析器来解析和验证输入 XML 文档（尽管它还可以将以前构造的 DOM 表示作为输入）。它包含一些转换器以将 JDOM 表示输出成 SAX2 事件流、DOM 模型或 XML 文本文档。JDOM 是在 Apache 许可证变体下发布的开放源码。

JDOM 在性能测试时表现不佳，在测试 10M 文档时内存溢出。在小文档情况下还值得考虑使用 JDOM。

生成xml文件示例

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;

public class JDOMsettest {
    public static void main(String[] args) throws FileNotFoundException,IOException {
        Element bookstore = new Element("Bookstore");
        Document document = new Document(bookstore);
        Element book1 = new Element("book");
        bookstore.addContent(book1);
        Element Name = new Element("Name");
        book1.addContent(Name);
        Element Author = new Element("Author");
        book1.addContent(Author);
        Element Type = new Element("Type");
        book1.addContent(Type);
        Element Price = new Element("Price");
        book1.addContent(Price);
        book1.setAttribute("id", "book1");
        book1.setAttribute("other", "这是第一本书");
        Name.setText("Get Me fLy");
        Author.setText("天哥哥");
        Price.setText("999RMB");
        Type.setText("励志");
        Format format = Format.getPrettyFormat();
        format.setEncoding("UTF-8");
        format.setIndent(" ");
        XMLOutputter xmlOutputter = new XMLOutputter(format);
        xmlOutputter.output(document, new FileOutputStream(newFile("BookstorebyJDOM.xml")));
        }
}

解析xml文件示例

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.jdom2.Attribute;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;

public class JDOMtest {
    static int bookindex;
    static List<Book> booklist = new ArrayList<Book>();
    static Book onebook = null;

    public static void main(String[] args) throws JDOMException, IOException {
        SAXBuilder saxBuilder = new SAXBuilder();
        Document document = saxBuilder.build(new File("Bookstore.xml"));
        Element bookstore = document.getRootElement();
        List<Element> books = bookstore.getChildren();
        for (int i = 0; i < books.size(); i++) {
            onebook = new Book();

            Element book = books.get(i);
            List<Attribute> bookAttributes = book.getAttributes();
            for (int j = 0; j < bookAttributes.size(); j++) {
                Attribute bookaAttribute = bookAttributes.get(j);
                if (bookaAttribute.getName() == "id") {
                    onebook.setId(bookaAttribute.getValue());
                }
                if (bookaAttribute.getName() == "other") {
                    onebook.setOther(bookaAttribute.getValue());
                }
            }
            List<Element> bookchilds = book.getChildren();
            for (int j = 0; j < bookchilds.size(); j++) {
                Element bookchild = bookchilds.get(j);
                if (bookchild.getName() == "Author") {
                    onebook.setAuthor(bookchild.getText());
                }
                if (bookchild.getName() == "Name") {
                    onebook.setName(bookchild.getText());
                }
                if (bookchild.getName() == "Price") {
                    onebook.setPrice(bookchild.getText());
                }
                if (bookchild.getName() == "Type") {
                    onebook.setType(bookchild.getText());
                }
            }
            booklist.add(onebook);

        }
        for (Book book : booklist) {
            System.out.println("=====存放入list然后输出第" + (++bookindex)
                    + "本书信息=====");
            System.out.println("该书编号：" + book.getId());
            System.out.println("该书名字：" + book.getName());
            System.out.println("该书作者：" + book.getAuthor());
            System.out.println("该书价格：" + book.getPrice());
            System.out.println("该书类型：" + book.getType());
            System.out.println("该书信息：" + book.getOther());
        }
    }
}

DOM4J

DOM4J是 JDOM 的一种智能分支。它合并了许多超出基本 XML 文档表示的功能，包括集成的 XPath 支持、XML Schema 支持以及用于大文档或流化文档的基于事件的处理。它还提供了构建文档表示的选项，它通过 DOM4J API 和标准 DOM 接口具有并行访问功能。DOM4J 大量使用了 API 中的 Collections 类，但是在许多情况下，它还提供一些替代方法以允许更好的性能或更直接的编码方法。直接好处是，虽然 DOM4J 付出了更复杂的 API 的代价，但是它提供了比 JDOM 大得多的灵活性。在添加灵活性、XPath 集成和对大文档处理的目标时，DOM4J 的目标与 JDOM 是一样的：针对 Java 开发者的易用性和直观操作。它还致力于成为比 JDOM 更完整的解决方案，实现在本质上处理所有 Java/XML 问题的目标。在完成该目标时，它比 JDOM 更少强调防止不正确的应用程序行为。

DOM4J 是一个非常非常优秀的Java XML API，具有性能优异、功能强大和极端易用使用的特点，同时它也是一个开放源代码的软件。如今你可以看到越来越多的 Java 软件都在使用 DOM4J 来读写 XML，特别值得一提的是连 Sun 的 JAXM 也在用 DOM4J。

生成xml文件示例

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.XMLWriter;

public class DOM4Jsettest {
    public static void main (String[]args) throws IOException {
        Document document = DocumentHelper.createDocument();
        Element bookstore = document.addElement("bookstore");
        Element book1 = bookstore.addElement("book");
        book1.addAttribute("id", "book1");
        book1.addAttribute("other", "这是第二本书");
        Element Name = book1.addElement("Name");
        Element Author = book1.addElement("Author");
        Element Type = book1.addElement("Type");
        Element Price = book1.addElement("Price");
        Author.addText("天哥哥");
        Name.addText("Get Me Fly");
        Price.addText("999RMB");
        Type.addText("励志");
        OutputFormat outputFormat = OutputFormat.createPrettyPrint();
                // 设置XML文档格式
        OutputFormat outputFormat = OutputFormat.createPrettyPrint();  
        // 设置XML编码方式,即是用指定的编码方式保存XML文档到字符串(String),这里也可以指定为GBK或是ISO8859-1  
        outputFormat.setEncoding("UTF-8");
        //outputFormat.setSuppressDeclaration(true); //是否生产xml头
        outputFormat.setIndent(true); //设置是否缩进
        outputFormat.setIndent("    "); //以四个空格方式实现缩进
        outputFormat.setNewlines(true); //设置是否换行
        outputFormat.setIndentSize(4);
        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(new File(
                "BookstorebyDOM4J.xml")), outputFormat);
        xmlWriter.write(document);
        xmlWriter.close();
    }
}

解析xml文件示例

import java.io.File;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

public class DOM4Jtest {
    static int bookindex;
    static Book oneBook;
    static List<Book> booklist = new ArrayList<Book>();

    @SuppressWarnings("unchecked")
    public static void main(String[] args) throws DocumentException {
        SAXReader saxReader = new SAXReader();
        Document document = saxReader.read(new File("Bookstore.xml"));
        Element bookstore = document.getRootElement();
        Iterator books = bookstore.elementIterator();

        while (books.hasNext()) {
            oneBook = new Book();
            Element book = (Element) books.next();

            List<Attribute> bookattributes = book.attributes();
            for (int i = 0; i < bookattributes.size(); i++) {
                Attribute bookattribute = bookattributes.get(i);
                if (bookattribute.getName() == "id") {
                    oneBook.setId(bookattribute.getValue());
                }
                if (bookattribute.getName() == "other") {
                    oneBook.setOther(bookattribute.getValue());
                }
            }
            Iterator bookchilds = book.elementIterator();
            while (bookchilds.hasNext()) {
                Element bookchild = (Element) bookchilds.next();
                if (bookchild.getName() == "Name") {
                    oneBook.setName(bookchild.getText());
                }
                if (bookchild.getName() == "Author") {
                    oneBook.setAuthor(bookchild.getText());
                }
                if (bookchild.getName() == "Price") {
                    oneBook.setPrice(bookchild.getText());
                }
                if (bookchild.getName() == "Type") {
                    oneBook.setType(bookchild.getText());
                }
            }
            booklist.add(oneBook);

        }
        for (Book book : booklist) {
            System.out.println("=====存放入list然后输出第" + (++bookindex)
                    + "本书信息=====");
            System.out.println("该书编号：" + book.getId());
            System.out.println("该书名字：" + book.getName());
            System.out.println("该书作者：" + book.getAuthor());
            System.out.println("该书价格：" + book.getPrice());
            System.out.println("该书类型：" + book.getType());
            System.out.println("该书信息：" + book.getOther());
        }
    }
}

public static void main(String[] args) throws DocumentException {
     String xml="<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
                + "<products>"
                + "<subject><subjectName>1</subjectName><subjectUrl>333</subjectUrl></subject>"
                + "</products>";
    //获取sax解析器对象
    SAXReader reader = new SAXReader();
    //转换字符串为java.io.Reader对象
    Reader stringReader=new StringReader(xml);
    //读取Reader对象，获取Document对象
    Document document=reader.read(stringReader);
    //获取根元素
    Element root = document.getRootElement();
    //获取根元素的名称
    String  rootName=root.getName();
    System.out.println("根节点名称： "+rootName);
    //获取子节点subject
    Element child1=root.element("subject");
    //获取子节点subjectName
    Element child2=child1.element("subjectName");
    String child2Name=child2.getName();
    String child2Text=child2.getText();
    System.out.println("子节点subjectName名称： "+child2Name);
    System.out.println("子节点subjectName内容： "+child2Text);
}