Java JDOM Document clone() 方法

Java JDOM 的clone()方法用于获取文档的深拷贝。它创建当前文档的精确副本。

语法

以下是 Java JDOM Document clone() 方法的语法：

Document.clone();

参数

Java clone() 方法不接受任何参数。

返回值

Java clone() 方法返回当前 Document 对象的副本。

示例 1

在这个基本示例中，我们创建了一个 XML 文档，并使用 Java JDOM Document clone() 方法获取其精确副本。

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

public class CloneDocument {
   public static void main(String args[]) {
      try {	
    	 //Create a new Document
	     Document doc = new Document();
	     //Create root Element
	     Element root = new Element("bookstore").setText("Coffee with Pages");
	     //Add root Element
	     doc.addContent(root);
	     //Cloning the document
	     Document cloneDoc = doc.clone();
	     //Printing document
	     XMLOutputter xmlOutput = new XMLOutputter();
	     System.out.println("-----------Original Document-----------\n");
	     xmlOutput.output(doc, System.out); 
	     System.out.println("\n-----------Cloned Document-----------\n");
         xmlOutput.output(cloneDoc, System.out);        
      } catch (Exception e) {
    	 e.printStackTrace();
      }
   }
}

输出窗口显示原始文档和克隆文档。

-----------Original Document-----------

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>Coffee with Pages</bookstore>

-----------Cloned Document-----------

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>Coffee with Pages</bookstore>

示例 2

我们需要克隆以下bookstore.xml文件：

<?xml version="1.0" encoding="UTF-8"?>
<!-- Information of a Bookstore (last updated o5-08-2024) -->
<bookstore>
	<!-- All the books in the store are listed -->
   <book>
      <name>Treasure Island</name>
	  <author>Robert Louis</author>
	  <price>1400</price>
   </book>
   <book>
      <name>Oliver Twist</name>
	  <author>Charles Dickens</author>
	  <price>2000</price>
   </book>
   <book>
      <name>War and Peace</name>
	  <author>Leo Tolstoy</author>
	  <price>1500</price>
   </book>
</bookstore>

让我们读取现有的 bookstore.xml 文件并获取此文档的克隆。为此，我们首先读取 bookstore.xml 文件，并使用 SAXBuilder 构建文档。然后，我们使用 clone() 方法获取此文档的深拷贝。

import java.io.File;
import org.jdom2.Document;
import org.jdom2.input.SAXBuilder;
import org.jdom2.output.Format;
import org.jdom2.output.XMLOutputter;

public class CloneDocument {
   public static void main(String args[]) {
      try {	
    	 //Reading the document
 		 SAXBuilder saxBuilder = new SAXBuilder();
 		 File inputFile = new File("bookstore.xml");
 		 Document doc = saxBuilder.build(inputFile);		 
	     //Cloning the document
	     Document cloneDoc = doc.clone();
	     //Printing document
	     XMLOutputter xmlOutput = new XMLOutputter();
	     xmlOutput.setFormat(Format.getPrettyFormat());
	     System.out.println("-----------Original Document-----------\n");	     
	     xmlOutput.output(doc, System.out); 
	     System.out.println("\n-----------Cloned Document-----------\n");
         xmlOutput.output(cloneDoc, System.out);        
      } catch (Exception e) {
    	 e.printStackTrace();
      }
   }
}

输出窗口显示原始 bookstore.xml 文件及其克隆文档。

-----------Original Document-----------

<?xml version="1.0" encoding="UTF-8"?>
<!-- Information of a Bookstore (last updated o5-08-2024) -->
<bookstore>
  <!-- All the books in the store are listed -->
  <book>
    <name>Treasure Island</name>
    <author>Robert Louis</author>
    <price>1400</price>
  </book>
  <book>
    <name>Oliver Twist</name>
    <author>Charles Dickens</author>
    <price>2000</price>
  </book>
  <book>
    <name>War and Peace</name>
    <author>Leo Tolstoy</author>
    <price>1500</price>
  </book>
</bookstore>

-----------Cloned Document-----------

<?xml version="1.0" encoding="UTF-8"?>
<!-- Information of a Bookstore (last updated o5-08-2024) -->
<bookstore>
  <!-- All the books in the store are listed -->
  <book>
    <name>Treasure Island</name>
    <author>Robert Louis</author>
    <price>1400</price>
  </book>
  <book>
    <name>Oliver Twist</name>
    <author>Charles Dickens</author>
    <price>2000</price>
  </book>
  <book>
    <name>War and Peace</name>
    <author>Leo Tolstoy</author>
    <price>1500</price>
  </book>
</bookstore>