从Java中的XML标记检索值

Question

I have a set of XML string outputs from a natural language tool and need to retrieve values out of them, also provide null value to those tags that are not presented in the output string. Tried to use the Java codes provided in Extracting data from XML using Java but it doesn't seem to work.

Current sample tag inventory is listed below:

<TimeStamp>, <Role>, <SpeakerId>, <Person>, <Location>, <Organization> 

Sample XML output string:

<TimeStamp>00.00.00</TimeStamp> <Role>Speaker1</Role><SpeakerId>1234</SpeakerId>Blah, blah, blah. 

Desire outputs:

TimeStamp: 00.00.00
Role: Speaker1
SpeakerId: 1234
Person: null
Place: null
Organization: null

In order to use the Java codes provided in above link (in updated code), I inserted <Dummy> and </Dummy> as follows:

<Dummy><TimeStamp>00.00.00</TimeStamp><Role>Speaker1</Role><SpeakerId>1234</SpeakerId>Blah, blah, blah.</Dummy>

However, it returns dummy and null only. Since I'm still a newbie to Java, detailed explanations will be much appreciated.

Answer 1

Try this way :D hope can help you

File fXmlFile = new File("yourfile.xml");
DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
Document doc = dBuilder.parse(fXmlFile);

You can get child node list like this:

NodeList nList = doc.getElementsByTagName("staff");

Get the item like this:

Node nNode = nList.item(temp);

Example Site

Answer 2

This is what I ended up doing for my Java wrapper (Show TimeStamp only)

  public class NERPost {

      public String convertXML (String input) {
      String nerOutput = input;
      try {
           DocumentBuilderFactory docBuilderFactory = 
           DocumentBuilderFactory.newInstance();
           DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
           InputSource is = new InputSource();            
           is.setCharacterStream(new StringReader(nerOutput));       
           Document doc = docBuilder.parse(is);

        // normalize text representation
        doc.getDocumentElement ().normalize ();
        NodeList listOfDummies = doc.getElementsByTagName("dummy");


        for(int s=0; s<listOfDummies.getLength() ; s++){
            Node firstDummyNode = listOfDummies.item(s);
            if(firstDummyNode.getNodeType() == Node.ELEMENT_NODE){
               Element firstDummyElement = (Element)firstDummyNode;

         //Convert each entity label --------------------------------

          //TimeStamp
               String ts = "<TimeStamp>";
               Boolean foundTs;

               if (foundTs = nerOutput.contains(ts)) {                    
           NodeList timeStampList = firstDummyElement.getElementsByTagName("TimeStamp");

          //do it recursively  
                for (int i=0; i<timeStampList.getLength(); i++) {       
                Node firstTimeStampNode = timeStampList.item(i);
                Element timeStampElement = (Element)firstTimeStampNode;
                NodeList textTSList = timeStampElement.getChildNodes();
                String timeStampOutput = ((Node)textTSList.item(0)).getNodeValue().trim();
                System.out.println ("<TimeStamp>" + timeStampOutput + "</TimeStamp>\n")
                   } //end for
                }//end if
             //other XML tags
              //.....
               }//end if
              }//end for
           }
            catch...
              }//end try
                }}