Nutch爬行给出错误“；来自位于的服务器的错误http://localhost:8983/solr/nutch: java.lang.NullPointerException“；

我正在尝试抓取一个网站，并使用Solr为其编制索引。我有一些自定义字段，它们是使用

UpdateRequestProcessor

更新的。我的自定义URP如下所示：

FieldProcessorFactory.java

FieldProcessor.java

schema.xml

---

可能出了什么问题？

我不太确定，可能是因为您可以告诉我们如何配置nutch来抓取数据或URL。我看到的一个问题可能发生在

processAdd

方法中，您没有将

Id

字段添加到Solr文档中，因为它是爬网后区分Solr索引中每个文档的必填字段。即使在

schema.xml

中，我也看不到任何

id

字段，因此我想知道索引将如何解释已爬网的文件。

如果

FieldProcessor.java

文件上的行数与异常中的行数匹配，那么这些行似乎来自：

String anchor = (String) cmd.getSolrInputDocument().get("anchor").getValue(); 

如果请求的字段不在

SolrInputDocument

实例中，我可以看到

get（key）

方法。您应该检查：

cmd.getSolrInputDocument().get("anchor")

返回一个非空值

---

根据我使用Nutch的经验，

anchor

字段并不总是出现在已爬网的文档中。另外，请记住，如果在模式中声明了一个字段，并不一定意味着所有文档都会有该字段（除非按要求指定，否则在这种情况下，如果它不存在，文档将在早期阶段被Solr拒绝）。

我只是将整个语句放在

try-catch

块中。现在它开始工作了。

<field name="title_length_i" type="int" stored="true" indexed="true"/>
    <field name="anchor_length_i" type="int" stored="true" indexed="true"/>
    <field name="body_length_i" type="int" stored="true" indexed="true"/>
    <field name="url_length_i" type="int" stored="true" indexed="true"/>
    <field name="whole_document_length_i" type="int" stored="true" indexed="true"/>

  <lib dir="${solr.install.dir:../../../..}/plugins/" regex="fieldProcessor.jar" />

  <updateRequestProcessorChain name="process-articles" lib="custom-libs" version="1">
      <processor class="ved.FieldProcessorFactory"/>
      <processor class="solr.LogUpdateProcessorFactory" />
      <processor class="solr.DistributedUpdateProcessorFactory" />
      <processor class="solr.RunUpdateProcessorFactory" />
  </updateRequestProcessorChain>

  <initParams path="/update/**,/query,/select,/tvrh,/elevate,/spell,/browse">
    <lst name="defaults">
      <str name="df">text</str>
      <str name="update.chain">process-articles</str>
    </lst>
  </initParams>

java.lang.Exception: org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Error from server at http://localhost:8983/solr/nutch: java.lang.NullPointerException
    at ved.FieldProcessor.processAdd(FieldProcessor.java:29)
    at org.apache.solr.handler.loader.JavabinLoader$1.update(JavabinLoader.java:98)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec$1.readOuterMostDocIterator(JavaBinUpdateRequestCodec.java:180)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec$1.readIterator(JavaBinUpdateRequestCodec.java:136)
    at org.apache.solr.common.util.JavaBinCodec.readObject(JavaBinCodec.java:306)
    at org.apache.solr.common.util.JavaBinCodec.readVal(JavaBinCodec.java:251)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec$1.readNamedList(JavaBinUpdateRequestCodec.java:122)
    at org.apache.solr.common.util.JavaBinCodec.readObject(JavaBinCodec.java:271)
    at org.apache.solr.common.util.JavaBinCodec.readVal(JavaBinCodec.java:251)
    at org.apache.solr.common.util.JavaBinCodec.unmarshal(JavaBinCodec.java:173)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec.unmarshal(JavaBinUpdateRequestCodec.java:187)
    at org.apache.solr.handler.loader.JavabinLoader.parseAndLoadDocs(JavabinLoader.java:108)
    at org.apache.solr.handler.loader.JavabinLoader.load(JavabinLoader.java:55)
    at org.apache.solr.handler.UpdateRequestHandler$1.load(UpdateRequestHandler.java:97)
    at org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:68)
    at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:173)
    at org.apache.solr.core.SolrCore.execute(SolrCore.java:2477)
    at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:723)
    at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:529)
    at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:361)
    at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:305)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1691)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:119)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
    at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
    at org.eclipse.jetty.server.Server.handle(Server.java:534)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273)
    at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95)
    at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)
    at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303)
    at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148)
    at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)
    at java.lang.Thread.run(Thread.java:748)

    at org.apache.hadoop.mapred.LocalJobRunner$Job.runTasks(LocalJobRunner.java:462)
    at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:529)
Caused by: org.apache.solr.client.solrj.impl.HttpSolrClient$RemoteSolrException: Error from server at http://localhost:8983/solr/nutch: java.lang.NullPointerException
    at ved.FieldProcessor.processAdd(FieldProcessor.java:29)
    at org.apache.solr.handler.loader.JavabinLoader$1.update(JavabinLoader.java:98)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec$1.readOuterMostDocIterator(JavaBinUpdateRequestCodec.java:180)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec$1.readIterator(JavaBinUpdateRequestCodec.java:136)
    at org.apache.solr.common.util.JavaBinCodec.readObject(JavaBinCodec.java:306)
    at org.apache.solr.common.util.JavaBinCodec.readVal(JavaBinCodec.java:251)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec$1.readNamedList(JavaBinUpdateRequestCodec.java:122)
    at org.apache.solr.common.util.JavaBinCodec.readObject(JavaBinCodec.java:271)
    at org.apache.solr.common.util.JavaBinCodec.readVal(JavaBinCodec.java:251)
    at org.apache.solr.common.util.JavaBinCodec.unmarshal(JavaBinCodec.java:173)
    at org.apache.solr.client.solrj.request.JavaBinUpdateRequestCodec.unmarshal(JavaBinUpdateRequestCodec.java:187)
    at org.apache.solr.handler.loader.JavabinLoader.parseAndLoadDocs(JavabinLoader.java:108)
    at org.apache.solr.handler.loader.JavabinLoader.load(JavabinLoader.java:55)
    at org.apache.solr.handler.UpdateRequestHandler$1.load(UpdateRequestHandler.java:97)
    at org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:68)
    at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:173)
    at org.apache.solr.core.SolrCore.execute(SolrCore.java:2477)
    at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:723)
    at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:529)
    at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:361)
    at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:305)
    at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1691)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
    at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:119)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
    at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)
    at org.eclipse.jetty.server.Server.handle(Server.java:534)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273)
    at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95)
    at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)
    at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303)
    at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148)
    at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)
    at java.lang.Thread.run(Thread.java:748)

    at org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:576)
    at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:240)
    at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:229)
    at org.apache.solr.client.solrj.SolrClient.request(SolrClient.java:1219)
    at org.apache.nutch.indexwriter.solr.SolrIndexWriter.push(SolrIndexWriter.java:210)
    at org.apache.nutch.indexwriter.solr.SolrIndexWriter.commit(SolrIndexWriter.java:188)
    at org.apache.nutch.indexwriter.solr.SolrIndexWriter.close(SolrIndexWriter.java:179)
    at org.apache.nutch.indexer.IndexWriters.close(IndexWriters.java:117)
    at org.apache.nutch.indexer.IndexerOutputFormat$1.close(IndexerOutputFormat.java:44)
    at org.apache.hadoop.mapred.ReduceTask$OldTrackingRecordWriter.close(ReduceTask.java:502)
    at org.apache.hadoop.mapred.ReduceTask.runOldReducer(ReduceTask.java:456)
    at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:392)
    at org.apache.hadoop.mapred.LocalJobRunner$Job$ReduceTaskRunnable.run(LocalJobRunner.java:319)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
2020-02-22 14:31:49,730 ERROR indexer.IndexingJob - Indexer: java.io.IOException: Job failed!
    at org.apache.hadoop.mapred.JobClient.runJob(JobClient.java:873)
    at org.apache.nutch.indexer.IndexingJob.index(IndexingJob.java:147)
    at org.apache.nutch.indexer.IndexingJob.run(IndexingJob.java:230)
    at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
    at org.apache.nutch.indexer.IndexingJob.main(IndexingJob.java:239)

String anchor = (String) cmd.getSolrInputDocument().get("anchor").getValue(); 

cmd.getSolrInputDocument().get("anchor")