我正在学习Java中的多线程。我正在使用执行程序服务（可调用）因为我需要最终收集我的结果并在进一步之前将它们组合起来。我实现了多线程并抛出错误，这是一个type.cast错误。只是为了让你知道，一旦多线程工作，并且它不起作用。对于每个线程返回类型是TreeMap。而且他们之间没有依赖关系。这是我的实施：
class AbnerCallable implements Callable<TreeMap<String, ArrayList>>{
TreeMap<String,ArrayList> maps;
AbnerCallable(TreeMap abs){
maps = abs;
}
@Override
public TreeMap call() throws Exception {
TreeMap<String,ArrayList> nerRes = new TreeMap<>();
AbstractTagger nerTagger = new AbstractTagger(maps);
nerRes = nerTagger.tagAbstracts();
System.out.println("######################One NER is finished.");
return nerRes;
}
}
public TreeMap NERmultithreading(TreeMap abstracts, int thread) throws InterruptedException, ExecutionException {
ListOperations breakList = new ListOperations();
//variable to store sum
TreeMap<String, ArrayList> abnerResultA = new TreeMap();
ArrayList<TreeMap<String, ArrayList>> abnerResultM = new ArrayList<>();
TreeMap<String, ArrayList> abnerResult = new TreeMap<>();
ExecutorService executor = Executors.newFixedThreadPool(thread);
List<Callable<TreeMap<String, ArrayList>>> callableList = new ArrayList<>();
//Send abstract TreeMap for division in TreeMaps
List<TreeMap> divTreemap = breakList.divideTreemap(abstracts);
//AbstractTagger nerTagger = new AbstractTagger();
System.out.println("Size of divTreeMap:"+divTreemap.size());
for (final TreeMap maps : divTreemap) {
System.out.println("TreeMap: "+maps.size());
Object[] mapKey = maps.keySet().toArray();
Callable<TreeMap<String, ArrayList>> nerCallable = new AbnerCallable(maps);
callableList.add(nerCallable);
}
System.out.println("Size of callable: "+callableList.size());
//Returns after all tasks complete
List<Future<TreeMap<String, ArrayList>>> resFuture = executor.invokeAll(callableList);
System.out.println("Size of future object: "+ resFuture.size());
//Print results as future objects
for (Future<TreeMap<String, ArrayList>> future : resFuture) {
System.out.println("Status of future : " + future.isDone());
abnerResultA = future.get();
abnerResultM.add(abnerResultA);
}
executor.shutdown();
abnerResult = breakList.joinMaps(abnerResultM);
System.out.println("Size of abner result: "+abnerResultM.size());
System.out.println("This is the abner map: "+abnerResultM);
return abnerResult;
}
public List divideTreemap(TreeMap abstracts) {
Object[] keyList = abstracts.keySet().toArray();
List<TreeMap> dividedAbsList = new ArrayList<>(); // To hold multiple TreeMaps
int size = abstracts.size();
System.out.println("Size:"+size);
//System.out.println(abstracts);
int divList = size / 4;
int lastElement = divList-1;
int firstElement = 0;
System.out.println("Check Point:1");
for (int i = 1; i <= 4; i++) {
System.out.println("i:"+i);
if (i < 4) {
TreeMap<String, Integer> las = new TreeMap<>(abstracts.subMap(keyList[firstElement], true, keyList[lastElement], true));
dividedAbsList.add((las));
firstElement = lastElement+1;
lastElement = lastElement + divList;
} else {
TreeMap<String, Integer> las = new TreeMap<>(abstracts.subMap(keyList[firstElement], true, keyList[size-1], true));
dividedAbsList.add(las);
}
}
return dividedAbsList;
}
这是parital output的错误示例....
Exception on pipe 27. java.lang.ArrayIndexOutOfBoundsException: 33860864
java.lang.ArrayIndexOutOfBoundsException: 33860864
at gnu.trove.TObjectIntHashMap.rehash(TObjectIntHashMap.java:171)
at gnu.trove.THash.postInsertHook(THash.java:243)
at gnu.trove.TObjectIntHashMap.put(TObjectIntHashMap.java:148)
at edu.umass.cs.mallet.base.types.Alphabet.lookupIndex(Alphabet.java:107)
at edu.umass.cs.mallet.base.types.AugmentableFeatureVector.<init>(AugmentableFeatureVector.java:88)
at edu.umass.cs.mallet.base.types.FeatureVectorSequence.<init>(FeatureVectorSequence.java:39)
at edu.umass.cs.mallet.base.pipe.TokenSequence2FeatureVectorSequence.pipe(TokenSequence2FeatureVectorSequence.java:60)
at edu.umass.cs.mallet.base.pipe.SerialPipes.pipe(SerialPipes.java:141)
at edu.umass.cs.mallet.base.pipe.SerialPipes.pipe(SerialPipes.java:217)
at edu.umass.cs.mallet.base.types.Instance.<init>(Instance.java:105)
at edu.umass.cs.mallet.base.types.InstanceList.add(InstanceList.java:741)
at de.bonn.limes.gcam.abner.MyTagger.doTagging(MyTagger.java:445)
at de.bonn.limes.gcam.abner.MyTagger.getEntities(MyTagger.java:297)
at de.bonn.limes.core.AbnerAnalysis.NERanalysis(AbnerAnalysis.java:91)
at de.bonn.limes.core.AbstractTagger.tagAbstracts(AbstractTagger.java:61)
at de.bonn.limes.core.ListOperations$AbnerCallable.call(ListOperations.java:48)
at de.bonn.limes.core.ListOperations$AbnerCallable.call(ListOperations.java:37)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Loading external tagging module from '/home/peeyush/Documents/netbeans_projects/GCAM-1.0/dependencies/nlpba.crf'...
Loading external tagging module from '/home/peeyush/Documents/netbeans_projects/GCAM-1.0/dependencies/nlpba.crf'...
######################One NER is finished.
######################One NER is finished.
Exception in thread "main" java.util.concurrent.ExecutionException: java.lang.ClassCastException: edu.umass.cs.mallet.base.types.TokenSequence cannot be cast to edu.umass.cs.mallet.base.types.FeatureVectorSequence
Size of future object: 4
Status of future : true
at java.util.concurrent.FutureTask.report(FutureTask.java:122)
at java.util.concurrent.FutureTask.get(FutureTask.java:192)
at de.bonn.limes.core.ListOperations.NERmultithreading(ListOperations.java:88)
at de.bonn.limes.core.Main.main(Main.java:208)
Caused by: java.lang.ClassCastException: edu.umass.cs.mallet.base.types.TokenSequence cannot be cast to edu.umass.cs.mallet.base.types.FeatureVectorSequence
at edu.umass.cs.mallet.base.fst.CRF4$State.transitionIterator(CRF4.java:1981)
at edu.umass.cs.mallet.base.fst.Transducer$ViterbiPath.<init>(Transducer.java:1080)
at edu.umass.cs.mallet.base.fst.Transducer.viterbiPath(Transducer.java:994)
at edu.umass.cs.mallet.base.fst.Transducer.viterbiPath(Transducer.java:986)
at de.bonn.limes.gcam.abner.MyTagger.doTagging(MyTagger.java:458)
at de.bonn.limes.gcam.abner.MyTagger.getEntities(MyTagger.java:297)
at de.bonn.limes.core.AbnerAnalysis.NERanalysis(AbnerAnalysis.java:91)
at de.bonn.limes.core.AbstractTagger.tagAbstracts(AbstractTagger.java:61)
at de.bonn.limes.core.ListOperations$AbnerCallable.call(ListOperations.java:48)
at de.bonn.limes.core.ListOperations$AbnerCallable.call(ListOperations.java:37)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
当我在单线程上运行时，我想再添加一些这些错误不在那里的东西。如果您需要更多信息，请与我们联系。 谢谢你提前帮忙。