如何使用xstream读取xml中的注释 [英] how to read comments in xml using xstream

问题描述

是否可以使用XStream和Java在解析XML注释时读取XML注释。

Is there a way to read xml comments while parsing it using XStream with Java.

<!--
 Mesh:  three-dimensional box 100m x 50m x 50m Created By Sumit Purohit on 
 for a stackoverflow query.
-->  
<ParameterList name="Mesh">  
 <Parameter name="Domain Low Corner" type="Array double" value="{0.0, 0.0,  0.0}" /> 
 <Parameter name="Domain High Corner" type="Array double" value="{100.0, 50.0,50.0}" /> 
</ParameterList>

我目前使用XStream对上述类型的xml进行序列化/反序列化。我需要将注释作为注释保存在POJO上，以便可以在UI中显示。

I currently use XStream to serialize/ de-serialize kind of xml above. I need to save comments as annotations on my POJO so that i can show it in UI.

在XStream中我找不到任何内容。

I could not find anything in XStream for that.

DOM具有 DocumentBuilderFactory.setIgnoringComments（boolean），可让您在DOM树中包含注释，并且可以区分节点的类型。

DOM has DocumentBuilderFactory.setIgnoringComments(boolean) that let you include comments in the DOM tree and you can distinguish between type of Nodes.

类似地，C＃具有 XmlReaderSettings.IgnoreComments

推荐答案

XStream无法处理XML注释。

XStream can not process XML comments to my knowledge.

这里是另一种方法，它使用LexicalHandler API：

Here is another approach, which uses the LexicalHandler API:

import org.xml.sax.*;
import org.xml.sax.ext.*;
import org.xml.sax.helpers.*;

import java.io.IOException;

public class ReadXMLFile implements LexicalHandler {

  public void startDTD(String name, String publicId, String systemId)
      throws SAXException {
  }

  public void endDTD() throws SAXException {
  }

  public void startEntity(String name) throws SAXException {
  }

  public void endEntity(String name) throws SAXException {
  }

  public void startCDATA() throws SAXException {
  }

  public void endCDATA() throws SAXException {
  }

  public void comment(char[] text, int start, int length)
      throws SAXException {

    System.out.println("Comment: " + new String(text, start, length));
  }

  public static void main(String[] args) {
    // set up the parser
    XMLReader parser;
    try {
      parser = XMLReaderFactory.createXMLReader();
    } catch (SAXException ex1) {
      try {
        parser = XMLReaderFactory.createXMLReader("org.apache.xerces.parsers.SAXParser");
      } catch (SAXException ex2) {
        return;
      }
    }

    try {
      parser.setProperty("http://xml.org/sax/properties/lexical-handler",new ReadXMLFile()
      );
    } catch (SAXNotRecognizedException e) {
      System.out.println(e.getMessage());
      return;
    } catch (SAXNotSupportedException e) {
      System.out.println(e.getMessage());
      return;
    }

    try {
      parser.parse("xmlfile.xml"); // <----  Path to XML file
    } catch (SAXParseException e) { // well-formedness error
      System.out.println(e.getMessage());
    } catch (SAXException e) { 
      System.out.println(e.getMessage());
    } catch (IOException e) {
    }
  }
}

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