Stanford parser java error

Question

I am working on a research about NLP, i woul to use Stanford parser to extract noun phrases from text, the parser version i used is 3.4.1 this is the sample code i used

package stanfordparser;


import java.util.Collection;
import java.util.List;
import java.io.StringReader;

import edu.stanford.nlp.process.Tokenizer;
import edu.stanford.nlp.process.TokenizerFactory;
import edu.stanford.nlp.process.CoreLabelTokenFactory;
import edu.stanford.nlp.process.DocumentPreprocessor;
import edu.stanford.nlp.process.PTBTokenizer;
import edu.stanford.nlp.ling.CoreLabel;
import edu.stanford.nlp.ling.HasWord;
import edu.stanford.nlp.ling.Sentence;
import edu.stanford.nlp.trees.*;
import edu.stanford.nlp.parser.lexparser.LexicalizedParser;

class ParserDemo {

  public static void main(String[] args) {
    LexicalizedParser lp = LexicalizedParser.loadModel("edu/stanford/nlp/models/lexparser/englishPCFG.ser.gz");
    if (args.length > 0) {
      demoDP(lp, args[0]);
    } else {
      demoAPI(lp);
    }
  }


  public static void demoDP(LexicalizedParser lp, String filename) {

    TreebankLanguagePack tlp = new PennTreebankLanguagePack();
    GrammaticalStructureFactory gsf = tlp.grammaticalStructureFactory();

    for (List<HasWord> sentence : new DocumentPreprocessor(filename)) {
      Tree parse = lp.apply(sentence);
      parse.pennPrint();
      System.out.println();

      GrammaticalStructure gs = gsf.newGrammaticalStructure(parse);
      Collection tdl = gs.typedDependenciesCCprocessed();
      System.out.println(tdl);
      System.out.println();
    }
  }

  public static void demoAPI(LexicalizedParser lp) {
    // This option shows parsing a list of correctly tokenized words
    String[] sent = { "This", "is", "an", "easy", "sentence", "." };
    List<CoreLabel> rawWords = Sentence.toCoreLabelList(sent);
    Tree parse = lp.apply(rawWords);
    parse.pennPrint();
    System.out.println();

    // This option shows loading and using an explicit tokenizer
    String sent2 = "This is another sentence.";
    TokenizerFactory<CoreLabel> tokenizerFactory =
        PTBTokenizer.factory(new CoreLabelTokenFactory(), "");
    Tokenizer<CoreLabel> tok =
        tokenizerFactory.getTokenizer(new StringReader(sent2));
    List<CoreLabel> rawWords2 = tok.tokenize();
    parse = lp.apply(rawWords2);

    TreebankLanguagePack tlp = new PennTreebankLanguagePack();
    GrammaticalStructureFactory gsf = tlp.grammaticalStructureFactory();
    GrammaticalStructure gs = gsf.newGrammaticalStructure(parse);
    List<TypedDependency> tdl = gs.typedDependenciesCCprocessed();
    System.out.println(tdl);
    System.out.println();

    // You can also use a TreePrint object to print trees and dependencies
    TreePrint tp = new TreePrint("penn,typedDependenciesCollapsed");
    tp.printTree(parse);
  }

  private ParserDemo() {} // static methods only

}

but when i run this code i get the following error

java.io.IOException: Unable to resolve "edu/stanford/nlp/models/lexparser/englishPCFG.ser.gz" as either class path, filename or URL
    at edu.stanford.nlp.io.IOUtils.getInputStreamFromURLOrClasspathOrFileSystem(IOUtils.java:446)
    at edu.stanford.nlp.io.IOUtils.readStreamFromString(IOUtils.java:380)
    at edu.stanford.nlp.parser.lexparser.LexicalizedParser.getParserFromSerializedFile(LexicalizedParser.java:628)
    at edu.stanford.nlp.parser.lexparser.LexicalizedParser.getParserFromFile(LexicalizedParser.java:423)
    at edu.stanford.nlp.parser.lexparser.LexicalizedParser.loadModel(LexicalizedParser.java:182)
    at edu.stanford.nlp.parser.lexparser.LexicalizedParser.loadModel(LexicalizedParser.java:161)
    at stanfordparser.ParserDemo.main(ParserDemo.java:29)

I think the problem in the loading of the model file, Could any one help me to solve the problem? Thanks

UPDATE:(1) I am already includes the cornlp model jar
UPDATE:(2) I am using Netbeans

Answer 1

Yes, You do not have CoreNLP models Jar. Either you can download them from here- http://nlp.stanford.edu/software/corenlp.shtml#Download

or, you can do this:

1. Create a Maven project. ( It is easy in eclipse)

2. In the pom.xml file, add this dependency.

   <dependency> 
     <groupId>edu.stanford.nlp</groupId>
     <artifactId>stanford-corenlp</artifactId>
     <version>3.5.0</version>
   </dependency>
   <dependency>
     <groupId>edu.stanford.nlp</groupId>
     <artifactId>stanford-corenlp</artifactId>
     <version>3.5.0</version>
     <classifier>models</classifier>
   </dependency>
   

3. Do maven clean, maven update and maven install. The model files will be installed in your .m2 folder automatically.

I hope you know maven. If not, please post a comment / question. We will answer.

Answer 2

As others have pointed out you have to include the jar files that come along with the CORE-NLP package that is avalaible at the stanford parser page.

More specifically add these to your class path : stanford-parser-3.4.1-models.jar,stanford-parser-3.4.1-sources.jar,stanford-parser.jar ( these are specific to the version of stanford parser you are using i.e version 3.4.1 )

You can add it to the class path as follows :

For Linux : export CLASSPATH=$CLASSPATH:/some_path/stanford-parser-3.4.1-sources.jar:/some_path/stanford-parser-3.4.1-models.jar:/some_path/stanford-parser.jar

For Windows : set CLASSPATH=%CLASSPATH%;\some_path\stanford-parser-3.4.1-models.jar;\some_path\stanford-parser-3.4.1-sources.jar;\some_path\stanford-parser;

Answer 3

You need to have the CoreNLP models jar (downloadable from the CoreNLP homepage) on your classpath for the parser to work properly.