我在 Android 上使用自然语言处理库 OpenNLP，首先我必须链接到一个模型，我在主要方法中这样做，例如，首先我实例化对象 InputStream，
public static InputStream is;
显然，对于初学者来说，它将是 null，但这就是我在 onCreate 类中将其初始化的原因，
is = getResources().openRawResource(R.raw.en);
在我的自定义类 AsyncTask 中，然后我继续使用一种方法将“R.raw.en”（这是我的原始资源中的 .bin 文件）引用到 SentenceModel 方法中：
SentenceModel model = new SentenceModel(is);
这就是引用出现问题的时候。我第一次运行代码时它没有问题，但是当应用程序崩溃时它第二次返回这个错误：
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.util.Properties.getProperty(java.lang.String)' on a null object reference
at opennlp.tools.util.model.BaseModel.getManifestProperty(BaseModel.java:506)
at opennlp.tools.util.model.BaseModel.initializeFactory(BaseModel.java:248)
at opennlp.tools.util.model.BaseModel.loadmodel(BaseModel.java:234)
at opennlp.tools.util.model.BaseModel.<init>(BaseModel.java:176)
at opennlp.tools.sentdetect.SentenceModel.<init>(SentenceModel.java:92)
at com.jwanhsulaiman.talktag.Post.sentenceDetect(Post.java:75)
at com.jwanhsulaiman.talktag.Post.onPostExecute(Post.java:102)
at com.jwanhsulaiman.talktag.Post.onPostExecute(Post.java:25)
at android.os.AsyncTask.finish(AsyncTask.java:695)
at android.os.AsyncTask.access$600(AsyncTask.java:180)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:712)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:280)
at android.app.activityThread.main(activityThread.java:6706)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
我完整的异步任务：
package com.jwanhsulaiman.talktag;
import android.annotation.SuppressLint;
import android.content.Context;
import android.os.AsyncTask;
import android.renderscript.ScriptGroup;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import edu.stanford.nlp.tagger.maxent.MaxentTagger;
import opennlp.tools.sentdetect.SentenceDetectorME;
import opennlp.tools.sentdetect.SentenceModel;
import opennlp.tools.util.InvalidFormatException;
import static com.jwanhsulaiman.talktag.Mainactivity.is;
public class Post extends AsyncTask<String,MaxentTagger,MaxentTagger> {
@SuppressLint("StaticFieldLeak")
private final EditText mEdtTxt;
@SuppressLint("StaticFieldLeak")
private final TextView mTxtMsg;
private String text;
@SuppressLint("StaticFieldLeak")
private final Spinner spinner;
private final List<String> senlist = new ArrayList<>();
public Post(EditText mEdtTxt,TextView mTxtMsg,Spinner spinner) throws IOException {
this.mEdtTxt = mEdtTxt;
this.mTxtMsg = mTxtMsg;
this.spinner = spinner;
}
public interface PostCallback{
void onSuccess(String sample);
void onError(Exception exception);
}
private PostCallback callback;
private Exception exception;
public void setPostCallback(PostCallback callback){
this.callback = callback;
}
@Override
protected MaxentTagger doInBackground(String... strings) {
// Do something that takes a long time,for example:
@SuppressLint("WrongThread") MaxentTagger tagger = new MaxentTagger(
"edu/stanford/nlp/models/" + spinner.getSelectedItem().toString() + ".tagger");
return tagger;
}
protected void onProgressUpdate(Integer... progress) {
}
public List<String> sentenceDetect(String trimmed) throws InvalidFormatException,IOException,URISyntaxException {
String paragraph = trimmed;
// refer to model file "en-sent,bin",available at link http://opennlp.sourceforge.net/models-1.5/
// load the model
SentenceModel model = new SentenceModel(is);
SentenceDetectorME sdetector = new SentenceDetectorME(model);
// detect sentences in the paragraph
String[] sentences = sdetector.sentDetect(paragraph);
// print the sentences detected,to console
for(int i=0;i<sentences.length;i++){
System.out.println(sentences[i]);
senlist.add(sentences[i]);
System.out.println(senlist);
}
return senlist;
}
@Override
public void onPostExecute(MaxentTagger tagger){
// Note: this will be executed on the main thread
if(exception == null){
callback.onSuccess(text);
//System.out.println(jsonObject.toString());
try {
mEdtTxt.findViewById(R.id.editText);
mTxtMsg.findViewById(R.id.message);
String sample = mEdtTxt.getText().toString();
String removedSpaces = sample.trim().replaceAll(" +"," ");
List<String> sentences = new ArrayList<>(sentenceDetect(removedSpaces));
for (int i = 0; i < sentences.size(); i++) {
String tagged = tagger.tagString(String.valueOf(sentences.get(i)));
}
//mTxtMsg.setText(tagged);
String[] wordsInSent = removedSpaces.split("\\s+");
for (int i = 0; i < wordsInSent.length; i++) {
// You may want to check for a non-word character before blindly
// performing a replacement
// It may also be necessary to adjust the character class
wordsInSent[i] = wordsInSent[i].replaceAll("[^\\w]","");
}
/**
StringTokenizer tokens = new StringTokenizer(tagged,"_");
String first = tokens.nextToken();
System.out.println(first);
String second = tokens.nextToken();
System.out.println(second);
**/
} catch (InvalidFormatException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (URISyntaxException e) {
e.printStackTrace();
} finally {
System.out.println("Whoopa");
}
} else if (exception != null) {
callback.onError(exception);
}
}
}
我尝试了调试器，在行 SentenceModel model = new SentenceModel(is); 处有一个断点，但没有产生任何有用的东西，这些值似乎是第一次存在：
第二次：
我尝试将方法移至 Mainactivity，但出现了更多 NullPointerExceptions。没有足够接近的问题存在，因为我已经被困了好几天了。感谢任何帮助！