无法实例化文档错误 Lucene 6.2.0 API

Question

I have started to use Lucene 6.2.0 in Java from the past couple of days and trying to parse a .trectext file containing tags. I believe I used the right parser to parse the tags, but however I have come across this weird error while creating a new Lucene Document which says Cannot instantiate the type Document . I kindly request that somebody help me with this, I do not see any suggestions regarding this over the internet nor does eclipse suggest any corrections. Not sure where I am going wrong. I have pasted the code below. `

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.StringField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.index.MultiFields;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.Terms;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.document.Field;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import java.io.File;
import java.io.FileFilter;
import java.io.FileReader;
import java.io.IOException;
import java.nio.file.Paths;
import java.io.Reader;
import java.util.Iterator;

public class Indexing {
public static void main(String argv[]) {
    String[] tags={"DOCNO","HEAD","BYLINE","DATELINE","TEXT"};
    try {
    String indexPath="C:\\Users\\sujit\\Desktop\\lucene_indexed"; //Path to create the Lucene Document Index.
    File fXmlFile = new File("C:\\Users\\sujit\\Desktop\\sample.txt"); //Path to find the document to be indexed.

    DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
    Document doc = dBuilder.parse(fXmlFile);
    doc.getDocumentElement().normalize();

    Analyzer analyzer=new StandardAnalyzer();
    Directory dir = FSDirectory.open(Paths.get(indexPath));
    IndexWriterConfig iwc = new IndexWriterConfig(analyzer);
    iwc.setOpenMode(OpenMode.CREATE);
    IndexWriter writer=new IndexWriter(dir,iwc);
    String DocNo="" ,Head="",ByLine="",DateLine="",Text="";

    //System.out.println("Root element :" + doc.getDocumentElement().getNodeName());
    NodeList nList = doc.getElementsByTagName("DOC");
    //System.out.println("----------------------------");
    for (int temp = 0; temp < nList.getLength(); temp++) {
        //**Place where I see the error **
        Document luceneDoc=new Document();

        Node nNode = nList.item(temp);
        System.out.println("\nCurrent Element :" + nNode.getNodeName());
        if (nNode.getNodeType() == Node.ELEMENT_NODE) {
            Element eElement = (Element) nNode;
            for(int tagNo=0;tagNo<tags.length;tagNo++){

                for(int j=0;j<eElement.getElementsByTagName(tags[tagNo]).getLength();j++){
                    if(tags[tagNo]==tags[0])
                       DocNo+=eElement.getElementsByTagName(tags[tagNo]).item(j).getTextContent();
                    else if(tags[tagNo]==tags[1])
                        Head+=eElement.getElementsByTagName(tags[tagNo]).item(j).getTextContent();
                    else if(tags[tagNo]==tags[2])
                        ByLine+=eElement.getElementsByTagName(tags[tagNo]).item(j).getTextContent();
                    else if(tags[tagNo]==tags[3])
                        DateLine+=eElement.getElementsByTagName(tags[tagNo]).item(j).getTextContent();
                    else if(tags[tagNo]==tags[4])
                        Text+=eElement.getElementsByTagName(tags[tagNo]).item(j).getTextContent();
                }
                System.out.println(DocNo+Head+ByLine+DateLine+Text+"\n");
                luceneDoc.add(new StringField("DOCNO",DocNo,Field.Store.YES));
                luceneDoc.add(new StringField("HEAD",Head,Field.Store.YES));
                luceneDoc.add(new StringField("BYLINE",ByLine,Field.Store.YES));
                luceneDoc.add(new StringField("DATELINE",DateLine,Field.Store.YES));
                luceneDoc.add(new StringField("TEXT",Text,Field.Store.YES));
                writer.addDocument(luceneDoc);
                DocNo="";Head="";ByLine="";DateLine="";Text="";
            }
            writer.close();
        }
    }
    } catch (Exception e) {
    e.printStackTrace();
    }
  }

}

Answer 1

You are importing org.w3c.dom.Document , instead of org.apache.lucene.document.Document . Since you appear to need both, you can just refer to one of them with it's full path, rather than importing it.