如何从结构类似于Java的XML文件中获取特定元素

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我有一个.sic-File，其结构类似于XML，但不完全相同。那里有我要阅读一些元素的Channel2部分。该部分是这样的：

.
.
.
<SI name = "Channel2" type = "list">
           <SI name = "SecsPortConfig" type = "list">
              <SI name = "PortType" type = "string">'XXX'</SI>
              <SI name = "Protocol" type = "string">'XXX'</SI>
              <SI name = "Serial" type = "list">
                 <SI name = "Port" type = "int">'XXX'</SI>
                 <SI name = "Speed" type = "int">'XXXX'</SI>
              </SI>
              <SI name = "Socket" type = "list">
                 <SI name = "ConnectionMode" type = "string">'XXX'</SI>
                 <SI name = "LocalHost" type = "string">'XXX.XXX.XXX.XXX'</SI>
                 <SI name = "LocalPort" type = "int">'XXX'</SI>
                 <SI name = "RemoteHost" type = "string">'XXX.XXX.XXX'</SI>
                 <SI name = "RemotePort" type = "int">'XXX'</SI>
              </SI>
              <SI name = "HSMS" type = "list">
                 <SI name = "T5" type = "int">'XXX'</SI>
                 <SI name = "T6" type = "int">'XXX'</SI>
                 <SI name = "T7" type = "int">'XXX'</SI>
                 <SI name = "T8" type = "int">'XXX'</SI>
                 <SI name = "LinkTestTime" type = "int">'XXX'</SI>
              </SI>
              <SI name = "SECSI" type = "list">
                 <SI name = "T1" type = "int">'XXX'</SI>
                 <SI name = "T2" type = "int">'XXX'</SI>
                 <SI name = "T4" type = "int">'XXX'</SI>
                 <SI name = "RTY" type = "int">'XXX'</SI>
                 <SI name = "IsHost" type = "bool">'XXX'</SI>
                 <SI name = "IsMaster" type = "bool">'XXX'</SI>
                 <SI name = "InterleaveBlocks" type = "bool">'XXX'</SI>
              </SI>
              <SI name = "SECSII" type = "list">
                 <SI name = "DeviceID" type = "int">'XXX'</SI>
                 <SI name = "T3" type = "int">'XXX'</SI>
                 <SI name = "MultipleOpen" type = "bool">'XXX'</SI>
                 <SI name = "AutoDeviceID" type = "bool">'XXX'</SI>
              </SI>
              <SI name = "Log" type = "list">
                 <SI name = "LogCharError" type = "bool">'XXX'</SI>
                 <SI name = "LogCharEvent" type = "bool">'XXX'</SI>
                 <SI name = "LogCharReceive" type = "bool">'XXX'</SI>
                 <SI name = "LogCharSend" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIHsmsError" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIHsmsEvent" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIHsmsReceive" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIHsmsSend" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIIError" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIIEvent" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIIReceive" type = "bool">'XXX'</SI>
                 <SI name = "LogSecsIISend" type = "bool">'XXX'</SI>
              </SI>
           </SI>
           <SI name = "UseSeparateSECSLogFile" type = "bool">'XXX'</SI>
           <SI name = "Connected" type = "bool">'XXX'</SI>
           <SI name = "MessageFilters" type = "list">
              <SI name = "DeviceIDList" type = "list"/>
              <SI name = "StreamFunctionList" type = "list"/>
           </SI>
           <SI name = "SafeMessageFilters" type = "list">
              <SI name = "DeviceIDList" type = "list"/>
              <SI name = "StreamFunctionList" type = "list"/>
           </SI>
        </SI>
        .
        .
        .

如果它将是一个xml文件，我可以解析它并读出元素，但是如何使用这种文件呢？我想提取元素RemoteHost和RemotePort。我现在使用BufferedReader进行了尝试，并将此节插入到字符串中，从而从文件中获得了节Channel2，但是如何提取所需元素的特定值？我可能可以用子字符串和其他一些String方法来做到这一点，但是没有更简单的方法吗？到目前为止，这是我的代码：

    File file = new File("C:\\Users\\but\\Desktop\\ExternalswPassThroughSrv.sic");

    int counter = 0;

    BufferedReader br = new BufferedReader(new FileReader(file));

    String cl;
    String finalString = "";
    while ((cl = br.readLine()) != null) 
        if (cl.contains("Channel2")) 
            counter = 63;
        
        if(counter != 0)
            //System.out.println(cl);
            finalString += cl + "\n";
            counter--;
        
    
    System.out.println(finalString);
答案
Document _myDoc = null;

LSInput input  = implLS.createLSInput();

input.setStringData(requestXML);

_myDoc = parser.parse(input);

SI = ((NodeList)_myDoc.getElementsByTagName("MessageFilters")).item(0).getFirstChild().getNodeValue();

您可以通过使用getElementsByTagName获得XML元素的节点值。但是为此，您需要使用不同的元素名称。这不是答案。这不是答案。只是提示。请尝试一下。

另一答案

由于我们不知道整个文件是如何形成的：即使它不是完整的XML文档，也可以通过添加根元素从文件的其余部分中提取XML片段，并将其转换为格式良好的XML文档。

之后，您可以将其解析为文档，并使用XPath提取所需的信息。

这里有一些适合您的Java代码示例（为清楚起见，我没有包含xml）

import org.w3c.dom.Document;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import java.io.IOException;
import java.io.StringReader;

public class ConvertXml 
    public static void main(String[] args) throws ParserConfigurationException, IOException, SAXException, TransformerException, XPathExpressionException 
        // Your XML-like content
        String xmlString = "xml here";

        // transform xml-Fragment into well-formed xml with root element
        String xmlStringWellformed = "<content>" + xmlString + "</content>";

        // parse well-formed xml
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        DocumentBuilder builder = factory.newDocumentBuilder();
        Document document = builder.parse(new InputSource(new StringReader(xmlStringWellformed)));

        // build xpath expression
        String xPathRemoteHost = "//SI[@name='Channel2']/SI[@name='SecsPortConfig']/SI[@name='Socket']/SI[@name='RemoteHost']/text()";
        String xPathRemotePort = "//SI[@name='Channel2']/SI[@name='SecsPortConfig']/SI[@name='Socket']/SI[@name='RemotePort']/text()";
        XPath xPath = XPathFactory.newInstance().newXPath();

        // Use XPath for extraction
        String remoteHost = (String) xPath.compile(xPathRemoteHost).evaluate(document, XPathConstants.STRING);
        String remotePort = (String) xPath.compile(xPathRemotePort).evaluate(document, XPathConstants.STRING);

        System.out.println("RemoteHost: " + remoteHost);
        System.out.println("RemotePort: " + remotePort);

来源：Baeldung - Intro to XPath with Java

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