使用CDATA_SECTION_ELEMENTS编组CDATA元素会添加回车符 [英] Marshalling CDATA elements with CDATA_SECTION_ELEMENTS adds carriage return characters

问题描述

我正在开发一个应用程序，该应用程序可将数据从数据库导出/导入数据库。数据提取的格式为XML，我正在使用JAXB进行序列化/（取消编组）。我希望将某些元素整理为CDATA元素，并正在使用此解决方案，它将 OutputKeys.CDATA_SECTION_ELEMENTS 设置为 Transformer 属性。

I'm working on an application that exports and imports data from / to a DB. The format of the data extract is XML and I'm using JAXB for the serialization / (un)marshalling. I want some elements to be marshalled as CDATA elements and am using this solution which sets OutputKeys.CDATA_SECTION_ELEMENTS to the Transformer properties.

到目前为止，它运行良好，但是现在我来到数据库中一个字段，该字段本身包含XML字符串，我也想将其放置在CDATA元素中。现在，由于某种原因， Transformer 现在在每行末尾添加了一些不必要的回车符（ \r ） ，因此输出看起来像这样：

So far this was working quite well, but now I came to a field in the DB that itself contains an XML string, which I also would like to place inside of a CDATA element. Now, for some reason the Transformer is now adding some unnecessary carriage return characters (\r) to each line end, so that the output looks like this:

这是我的代码：

  private static final String IDENT_LENGTH = "3";
  private static final String CDATA_XML_ELEMENTS = "text definition note expression mandatoryExpression optionalExpression settingsXml";

  public static void marshall(final Object rootObject, final Schema schema, final Writer writer) throws Exception {
    final JAXBContext ctx = JAXBContext.newInstance(rootObject.getClass());
    final Document document = createDocument();
    final Marshaller marshaller = ctx.createMarshaller();
    marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
    marshaller.setSchema(schema);
    marshaller.marshal(rootObject, document);
    createTransformer().transform(new DOMSource(document), new StreamResult(writer));
  }

  private static Document createDocument() throws ParserConfigurationException {
    // the DocumentBuilderFactory is actually being hold in a singleton
    final DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
    return builderFactory.newDocumentBuilder().newDocument();
  }

  private static Transformer createTransformer() throws TransformerConfigurationException, TransformerFactoryConfigurationError {
    // the TransformerFactory is actually being hold in a singleton
    final TransformerFactory transformerFactory = TransformerFactory.newInstance();
    final Transformer transformer = transformerFactory.newTransformer();
    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
    transformer.setOutputProperty(OutputKeys.STANDALONE, "yes");
    transformer.setOutputProperty(OutputKeys.CDATA_SECTION_ELEMENTS, CDATA_XML_ELEMENTS);
    transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", IDENT_LENGTH);
    return transformer;
  }

我正在传递 FileWriter 到 marshall 方法。

我带注释的模型类如下：

My annotated model class looks like this:

@XmlType
@XmlRootElement
public class DashboardSettings {

  @XmlElement
  private String settingsXml;

  public String getSettingsXml() {
    return settingsXml;
  }

  public void setSettingsXml(final String settingsXml) {
    this.settingsXml = settingsXml;
  }
}

注意：

来自数据库的XML字符串具有Windows样式的行尾，即 \r 和 \n 。我感觉JAXB期望当前使用Linux风格的输入（即仅 \n ），因此正在添加 \r 字符，因为我当前正在Windows计算机上运行。所以问题是，解决这个问题的最佳方法是什么？编组时是否可以传递任何参数来控制行尾字符？还是应该在编组之前将行尾转换为Linux样式？我的程序在不同平台（Windows，Linux，Mac OS）上的行为如何？

The XML string coming from the DB has Windows style line endings, i.e. \r and \n. I have the feeling that JAXB expects currently Linux style input (i. e. only \n) and is therefore adding a \r character because I'm currently running on a Windows machine. So the question is actually, what's the best way to solve this? Is there any parameter I can pass to control the line ending characters when marshalling? Or should I convert the line endings to Linux style prior marshalling? How will my program behave on different platforms (Windows, Linux, Mac OS)?

我不一定需要独立于平台的解决方案，如果输出在Windows，Linux或任何样式。我要避免的是组合 \r\r\n ，如上面的屏幕截图所示。

I don't necessarily need a platform independent solution, it's OK if the output is in Windows, Linux or whatever style. What I want to avoid is the combination \r\r\n as shown in the above screenshot.

推荐答案

我意识到这个问题已经很老了，但是我遇到了类似的问题，所以也许答案可以对其他人有所帮助。

I realise this question is pretty old, but I ran into a similar problem, so maybe an answer can help someone else.

CDATA部分似乎是一个问题。就我而言，我使用的是 createCDATASection 方法来创建它们。如在您的示例中那样，当代码在Windows计算机上运行时，添加了附加的 CR 。

It seems to be an issue with CDATA sections. In my case, I was using the createCDATASection method to create them. When the code was running on a Windows machine, an additional CR was added, as in your example.

I

在我的项目中，XML文档随后被导出为字符串，然后以POST的形式发布到Linux服务器。因此，一旦生成字符串，我就删除了 CR 个字符，只剩下了 LF ：

In my project, the XML document was then exported to a string to POST to a Linux server. So once the string was generated, I just removed the CR characters, leaving only the LF:

myXmlString.replaceAll("\\r", "");

对于特定的问题，我可能不是一个合适的解决方案，但它可能再次为您提供帮助（

I might not be an appropriate solution for the specific question, but once again, it may help you (or someone else) find a solution.

注意：对于该特定项目，我坚持使用Java 7，因此它可能已修复。在较新的版本中。

Note: I'm stuck with Java 7 for this specific project, so it may have been fixed in a more recent version.

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