自定义一个书架(或自定义一个XML)文档,带有DTD或Schema约束,用Dom4j并完成对其的读写操作
时间: 2024-02-22 22:56:43 浏览: 64
好的,我可以为您提供一个示例来帮助您了解如何使用Dom4j来读写具有DTD或Schema约束的自定义XML文档。
首先,我们需要定义一个XML文档,例如一个书架,它包含书籍的信息。下面是一个示例XML文件:
```xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE bookshelf SYSTEM "bookshelf.dtd">
<bookshelf>
<book>
<title>Java编程思想</title>
<author>Bruce Eckel</author>
<publisher>机械工业出版社</publisher>
<price>108.00</price>
</book>
<book>
<title>Effective Java</title>
<author>Joshua Bloch</author>
<publisher>机械工业出版社</publisher>
<price>78.00</price>
</book>
</bookshelf>
```
接下来,我们需要定义一个DTD或Schema约束,以确保XML文档的正确性。这里我们使用一个DTD约束,定义为bookshelf.dtd:
```xml
<!ELEMENT bookshelf (book+)>
<!ELEMENT book (title, author, publisher, price)>
<!ELEMENT title (#PCDATA)>
<!ELEMENT author (#PCDATA)>
<!ELEMENT publisher (#PCDATA)>
<!ELEMENT price (#PCDATA)>
```
现在,我们可以使用Dom4j来读取和写入这个XML文档。下面是一个示例代码:
```java
import java.io.File;
import java.io.FileWriter;
import java.util.Iterator;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;
public class BookshelfDemo {
public static void main(String[] args) {
// 读取XML文档
try {
SAXReader reader = new SAXReader();
Document document = reader.read(new File("bookshelf.xml"));
// 获取根节点bookshelf
Element root = document.getRootElement();
// 遍历所有book节点
Iterator<Element> bookIterator = root.elementIterator("book");
while (bookIterator.hasNext()) {
Element book = bookIterator.next();
// 获取书籍信息
String title = book.elementText("title");
String author = book.elementText("author");
String publisher = book.elementText("publisher");
double price = Double.parseDouble(book.elementText("price"));
// 输出书籍信息
System.out.println("Title: " + title);
System.out.println("Author: " + author);
System.out.println("Publisher: " + publisher);
System.out.println("Price: " + price);
System.out.println();
}
} catch (DocumentException e) {
e.printStackTrace();
}
// 写入XML文档
try {
// 创建根节点bookshelf
Element root = DocumentHelper.createElement("bookshelf");
Document document = DocumentHelper.createDocument(root);
// 创建书籍节点
Element book1 = root.addElement("book");
book1.addElement("title").addText("Java编程思想");
book1.addElement("author").addText("Bruce Eckel");
book1.addElement("publisher").addText("机械工业出版社");
book1.addElement("price").addText("108.00");
Element book2 = root.addElement("book");
book2.addElement("title").addText("Effective Java");
book2.addElement("author").addText("Joshua Bloch");
book2.addElement("publisher").addText("机械工业出版社");
book2.addElement("price").addText("78.00");
// 写入XML文件
FileWriter fileWriter = new FileWriter("new_bookshelf.xml");
XMLWriter xmlWriter = new XMLWriter(fileWriter);
xmlWriter.write(document);
xmlWriter.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
```
运行此代码将输出每本书的信息,并在同一目录下生成一个名为new_bookshelf.xml的新XML文件。您可以根据需要修改此示例代码以适应您的特定需求。