在 Java 中生成 XML 时转义特殊字符

java special-characters xml

2022-09-01 08:41:53

我正在尝试开发一个 XML 导出功能，以使我的应用程序用户能够以 XML 格式导出其数据。我已经准备好了这个功能，并一直工作到它在某些情况下开始失败。然后我意识到这是因为一些特殊字符需要编码。例如，数据可能包含 & 或！或 %或 ' 或 # 等，这需要正确转义。我想知道是否有一个通用实用程序可以按照XML规范转义所有特殊字符。我在谷歌上找不到任何东西。

有没有类似的东西已经存在了？或者有没有其他方法可以做到这一点？

以下是我用来生成 XML 的代码


Document xmldoc = new DocumentImpl();
Element root = xmldoc.createElement("Report");

Element name= xmldoc.createElement((exportData.getChartName() == null) ? "Report" : exportData.getChartName());
if (exportData.getExportDataList().size() > 0
    && exportData.getExportDataList().get(0) instanceof Vector) {
    // First row is the HEADER, i.e name
    Vector name = exportData.getExportDataList().get(0);
    for (int i = 1; i  value = exportData.getExportDataList().get(i);
        Element sub_root = xmldoc.createElement("Data");
        //I had to remove a for loop from here. StackOverflow description field would not take that. :(
            // Insert header row
            Element node = xmldoc.createElementNS(null, replaceUnrecognizedChars(name.get(j)));
            Node node_value = xmldoc.createTextNode(value.get(j));
            node.appendChild(node_value);
            sub_root.appendChild(node);
            chartName.appendChild(sub_root);
        }
    }
}
root.appendChild(name);

// Prepare the DOM document for writing
Source source = new DOMSource(root);

// Prepare the output file
Result result = new StreamResult(file);

// Write the DOM document to the file
Transformer xformer = TransformerFactory.newInstance().newTransformer();
xformer.transform(source, result);`

示例 XML：


<Data>
    <TimeStamp>2010-08-31 00:00:00.0</TimeStamp>
    <[Name that needs to be encoded]>0.0</[Name that needs to be encoded]>
    <Group_Average>1860.0</Group_Average>
</Data>

答案 1

您可以使用 apache 通用 lang 库来转义字符串。

org.apache.commons.lang.StringEscapeUtils

String escapedXml = StringEscapeUtils.escapeXml("the data might contain & or ! or % or ' or # etc");

但是，您要查找的是一种将任何字符串转换为有效 XML 标记名称的方法。对于 ASCII 字符，XML 标记名称必须以 _：a-zA-Z 之一开头，后跟 _：a-zA-Z0-9 中任意数量的字符。

我当然相信没有库可以为您执行此操作，因此您必须实现自己的函数以从任何字符串转换为与此模式匹配，或者将其转换为attritbue值。

<property name="no more need to be encoded, it should be handled by XML library">0.0</property>

答案 2

public class RssParser {
int length;
    URL url;
URLConnection urlConn;
NodeList nodeList;
Document doc;
Node node;
Element firstEle;
NodeList titleList;
Element ele;
NodeList txtEleList;
String retVal, urlStrToParse, rootNodeName;

public RssParser(String urlStrToParse, String rootNodeName){
    this.urlStrToParse = urlStrToParse;
    this.rootNodeName = rootNodeName;

    url=null;
    urlConn=null;
    nodeList=null;
    doc=null;
    node=null;
    firstEle=null;
    titleList=null;
    ele=null;
    txtEleList=null;
    retVal=null;
            doc = null;
    try {
        url = new URL(this.urlStrToParse);
                    // dis is path of url which v'll parse
        urlConn = url.openConnection();

                    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();

        String s = isToString(urlConn.getInputStream());
        s = s.replace("&", "&amp;");
        StringBuilder sb =
                            new StringBuilder
                                    ("<?xml version=\"1.0\" encoding=\"utf-8\"?>");
        sb.append("\n"+s);
        System.out.println("STR: \n"+sb.toString());
        s = sb.toString();

        doc = db.parse(urlConn.getInputStream());
        nodeList = doc.getElementsByTagName(this.rootNodeName); 
        //  dis is d first node which
        //  contains other inner element-nodes
        length =nodeList.getLength();
        firstEle=doc.getDocumentElement();
    }
    catch (ParserConfigurationException pce) {
        System.out.println("Could not Parse XML: " + pce.getMessage());
    }
    catch (SAXException se) {
        System.out.println("Could not Parse XML: " + se.getMessage());
    }
    catch (IOException ioe) {
        System.out.println("Invalid XML: " + ioe.getMessage());
    }
    catch(Exception e){
        System.out.println("Error: "+e.toString());
    }
}


public String isToString(InputStream in) throws IOException {
    StringBuffer out = new StringBuffer();
    byte[] b = new byte[512];
    for (int i; (i = in.read(b)) != -1;) {
        out.append(new String(b, 0, i));
    }
    return out.toString();
}

public String getVal(int i, String param){
    node =nodeList.item(i);
    if(node.getNodeType() == Node.ELEMENT_NODE)
    {
        System.out.println("Param: "+param);
        titleList = firstEle.getElementsByTagName(param);
        if(firstEle.hasAttribute("id"))
        System.out.println("hasAttrib----------------");
        else System.out.println("Has NOTNOT      NOT");
        System.out.println("titleList: "+titleList.toString());
    ele = (Element)titleList.item(i);
    System.out.println("ele: "+ele);
        txtEleList = ele.getChildNodes();
    retVal=(((Node)txtEleList.item(0)).getNodeValue()).toString();
    if (retVal == null)
        return null;
            System.out.println("retVal: "+retVal);
    }
return retVal;
}
}