Java 使用hadoop文件系统API模拟hadoop fs命令（hadoop fs-cat）

我们有一个运行在JBoss上的服务，它从远程服务器检索文件。 由于过去的情况，我们无法使用Hadoop FS API，因此我们使用实际命令的系统调用（我们使用：Hadoop FS-cat）

现在，我们将这些系统调用转移到它们的等效API Hadoop FS API

我需要以InputStream（或FSDataInputStream）的形式从HDFS获取文件，并将其传递给http响应。 我们希望避免在本地保存文件，然后将其写入流

基本上这是可行的，但我面临两个问题

我不知道什么时候可以调用FileSystem.close（），因为我不知道流是否完成

流结束后，我得到一个EOFEException：

19:09:41,446 INFO  [STDOUT] [DEBUG] [http-127.0.0.1-8888-1] Error making BlockReader. Closing stale NioInetPeer(Socket[addr=/192.168.20.198,port=50010,localport=56503]) [org.apache.hadoop.hdfs.DFSClient]
java.io.EOFException: Premature EOF: no length prefix available
at org.apache.hadoop.hdfs.protocol.HdfsProtoUtil.vintPrefixed(HdfsProtoUtil.java:171)
at org.apache.hadoop.hdfs.RemoteBlockReader2.newBlockReader(RemoteBlockReader2.java:392)
at org.apache.hadoop.hdfs.BlockReaderFactory.newBlockReader(BlockReaderFactory.java:137)
at org.apache.hadoop.hdfs.DFSInputStream.getBlockReader(DFSInputStream.java:1084)
at org.apache.hadoop.hdfs.DFSInputStream.blockSeekTo(DFSInputStream.java:538)
at org.apache.hadoop.hdfs.DFSInputStream.readWithStrategy(DFSInputStream.java:750)
at org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:794)
at java.io.DataInputStream.read(DataInputStream.java:83)
at com.sun.jersey.core.util.ReaderWriter.writeTo(ReaderWriter.java:114)
at com.sun.jersey.core.provider.AbstractMessageReaderWriterProvider.writeTo(AbstractMessageReaderWriterProvider.java:76)
at com.sun.jersey.core.impl.provider.entity.InputStreamProvider.writeTo(InputStreamProvider.java:98)
at com.sun.jersey.core.impl.provider.entity.InputStreamProvider.writeTo(InputStreamProvider.java:59)
at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:306)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1437)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:708)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.liveperson.dataaccess.management.filters.DevFilter.doFilter(DevFilter.java:60)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.liveperson.dataaccess.management.filters.ValidationFilter.doFilter(ValidationFilter.java:74)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.liveperson.gatekeeper.oauth.filter.GateKeeperFilter.doFilter(GateKeeperFilter.java:117)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.liveperson.dataaccess.management.filters.CountersFilter.doFilter(CountersFilter.java:32)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:601)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:662)

提前感谢您的帮助