Stanford CoreNLP给出了NullPointerException

我正试图了解斯坦福CoreNLP API。 我希望使用以下代码将一个简单的句子标记为：

Properties props = new Properties(); props.put("annotators", "tokenize"); StanfordCoreNLP pipeline = new StanfordCoreNLP(props); // read some text in the text variable String text = "I wish this code would run."; // create an empty Annotation just with the given text Annotation document = new Annotation(text); // run all Annotators on this text pipeline.annotate(document); // these are all the sentences in this document // a CoreMap is essentially a Map that uses class objects as keys and has values with custom types List sentences = document.get(SentencesAnnotation.class); for(CoreMap sentence: sentences) { // traversing the words in the current sentence // a CoreLabel is a CoreMap with additional token-specific methods for (CoreLabel token: sentence.get(TokensAnnotation.class)) { // this is the text of the token String word = token.get(TextAnnotation.class); // this is the POS tag of the token String pos = token.get(PartOfSpeechAnnotation.class); // this is the NER label of the token String ne = token.get(NamedEntityTagAnnotation.class); } // this is the parse tree of the current sentence Tree tree = sentence.get(TreeAnnotation.class); // this is the Stanford dependency graph of the current sentence SemanticGraph dependencies = sentence.get(CollapsedCCProcessedDependenciesAnnotation.class); } // This is the coreference link graph // Each chain stores a set of mentions that link to each other, // along with a method for getting the most representative mention // Both sentence and token offsets start at 1! Map graph = document.get(CorefChainAnnotation.class); 

这是从斯坦福NLP网站本身挑选的，所以我希望它开箱即用。 可悲的是它没有，因为它给了我一个NullPointerException：

 for(CoreMap sentence: sentences) {... 

Answer 1

您从Stanford NLP网站上获取的代码会对文本变量执行所有注释。 为了执行特定的注释，您必须相应地更改代码。

要执行标记化，这就足够了

 Properties props = new Properties(); props.put("annotators", "tokenize"); StanfordCoreNLP pipeline = new StanfordCoreNLP(props); Annotation document = new Annotation(text); pipeline.annotate(document); for (CoreLabel token: document.get(TokensAnnotation.class)) { String word = token.get(TextAnnotation.class); } 

如果注释器不包含Sentence Splitter（“ssplit”），这行代码将返回Null

 document.get(SentencesAnnotation.class); 

所以你遇到了NullPointerException。

Answer 2

该行检索句子注释。

 List sentences = document.get(SentencesAnnotation.class); 

但是你的管道只包含tokenizer，而不是句子分割器。

更改以下行：

     props.put（“annotators”，“tokenize， ssplit ”）;  //添加句子分割器