java.net.SocketTimeoutException : Read timed out when I run a query on DBPedia

Question

我有一个问题:

我有一个代码可以调用 DBPedia 上的不同查询。这是我的代码:

ResIterator resi = model.listSubjects();

    while (resi.hasNext()) {
        Resource subject = resi.nextResource();

                QueryExecution exec1 = queryDBPedia(subject);
                ResultSet results1 = ResultSetFactory.copyResults(exec1.execSelect());

                if (results1.hasNext()) {
                    while (results1.hasNext()) {
                        QuerySolution qs = results1.next();

                        if (qs.get("resource") != null) {
                           //TO DO SOMETHING
                        }
                    }
                }

                exec1.close();
            }

在我的模型中，我有 100 多个资源。当我使用 Netbeans 和 Glassfish 4.0 在 Web 服务(带有客户端)中运行此代码时，出现以下错误:

Caused by: java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:152)
    at java.net.SocketInputStream.read(SocketInputStream.java:122)
    at org.apache.http.impl.io.AbstractSessionInputBuffer.fillBuffer(AbstractSessionInputBuffer.java:166)
    at org.apache.http.impl.io.SocketInputBuffer.fillBuffer(SocketInputBuffer.java:90)
    at org.apache.http.impl.io.AbstractSessionInputBuffer.readLine(AbstractSessionInputBuffer.java:281)
    at org.apache.http.impl.conn.LoggingSessionInputBuffer.readLine(LoggingSessionInputBuffer.java:115)
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:92)
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:61)
    at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:254)
    at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:289)
    at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:252)
    at org.apache.http.impl.conn.ManagedClientConnectionImpl.receiveResponseHeader(ManagedClientConnectionImpl.java:191)
    at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:300)
    at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:127)
    at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:715)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:520)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
    at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:137)
    at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:118)
    at org.apache.jena.riot.web.HttpOp.exec(HttpOp.java:1109)
    at org.apache.jena.riot.web.HttpOp.execHttpGet(HttpOp.java:384)
    at org.apache.jena.riot.web.HttpOp.execHttpGet(HttpOp.java:446)
    at com.hp.hpl.jena.sparql.engine.http.HttpQuery.execGet(HttpQuery.java:346)
    ... 94 more

Avvertenza:   javax.ejb.EJBException
    at com.sun.ejb.containers.EJBContainerTransactionManager.processSystemException(EJBContainerTransactionManager.java:748)
    at com.sun.ejb.containers.EJBContainerTransactionManager.completeNewTx(EJBContainerTransactionManager.java:698)
    at com.sun.ejb.containers.EJBContainerTransactionManager.postInvokeTx(EJBContainerTransactionManager.java:503)
    at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4475)
    at com.sun.ejb.containers.WebServiceInvocationHandler.invoke(WebServiceInvocationHandler.java:205)
    at com.sun.proxy.$Proxy258.publishLinkedOpenData(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.glassfish.webservices.InvokerImpl.invoke(InvokerImpl.java:82)
    at org.glassfish.webservices.EjbInvokerImpl.invoke(EjbInvokerImpl.java:82)
    at com.sun.xml.ws.server.InvokerTube$2.invoke(InvokerTube.java:149)
    at com.sun.xml.ws.server.sei.SEIInvokerTube.processRequest(SEIInvokerTube.java:88)
    at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
    at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
    at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
    at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
    at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:136)
    at org.glassfish.webservices.MonitoringPipe.process(MonitoringPipe.java:142)
    at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:119)
    at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
    at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
    at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
    at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
    at com.sun.xml.ws.api.pipe.helper.AbstractTubeImpl.process(AbstractTubeImpl.java:136)
    at com.sun.enterprise.security.webservices.CommonServerSecurityPipe.processRequest(CommonServerSecurityPipe.java:210)
    at com.sun.enterprise.security.webservices.CommonServerSecurityPipe.process(CommonServerSecurityPipe.java:142)
    at com.sun.xml.ws.api.pipe.helper.PipeAdapter.processRequest(PipeAdapter.java:119)
    at com.sun.xml.ws.api.pipe.Fiber.__doRun(Fiber.java:1136)
    at com.sun.xml.ws.api.pipe.Fiber._doRun(Fiber.java:1050)
    at com.sun.xml.ws.api.pipe.Fiber.doRun(Fiber.java:1019)
    at com.sun.xml.ws.api.pipe.Fiber.runSync(Fiber.java:877)
    at com.sun.xml.ws.server.WSEndpointImpl$2.process(WSEndpointImpl.java:420)
    at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:687)
    at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:266)
    at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:169)
    at org.glassfish.webservices.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:110)
    at org.glassfish.webservices.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:80)
    at org.glassfish.webservices.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:203)
    at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:146)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.glassfish.grizzly.servlet.ServletHandler.doServletService(ServletHandler.java:242)
    at org.glassfish.grizzly.servlet.ServletHandler.service(ServletHandler.java:193)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:246)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:191)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:168)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:189)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:288)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:206)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:136)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:114)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:838)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:113)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:115)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:55)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:135)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:564)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:544)
    at java.lang.Thread.run(Thread.java:744)
Caused by: HttpException: java.net.SocketTimeoutException: Read timed out: Unexpected error making the query: java.net.SocketTimeoutException: Read timed out
    at com.hp.hpl.jena.sparql.engine.http.HttpQuery.rewrap(HttpQuery.java:417)
    at com.hp.hpl.jena.sparql.engine.http.HttpQuery.execGet(HttpQuery.java:358)
    at com.hp.hpl.jena.sparql.engine.http.HttpQuery.exec(HttpQuery.java:295)
    at com.hp.hpl.jena.sparql.engine.http.QueryEngineHTTP.execSelect(QueryEngineHTTP.java:346)
    at Prova.Prova.test(Prova.java:317)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1081)
    at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1153)
    at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:4695)
    at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:630)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
    at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:55)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:582)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doCall(SystemInterceptorProxy.java:163)
    at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:140)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:883)
    at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:822)
    at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:369)
    at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:4667)
    at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:4655)
    at com.sun.ejb.containers.WebServiceInvocationHandler.invoke(WebServiceInvocationHandler.java:193)
    ... 57 more
Caused by: java.net.SocketTimeoutException: Read timed out
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.read(SocketInputStream.java:152)
    at java.net.SocketInputStream.read(SocketInputStream.java:122)
    at org.apache.http.impl.io.AbstractSessionInputBuffer.fillBuffer(AbstractSessionInputBuffer.java:166)
    at org.apache.http.impl.io.SocketInputBuffer.fillBuffer(SocketInputBuffer.java:90)
    at org.apache.http.impl.io.AbstractSessionInputBuffer.readLine(AbstractSessionInputBuffer.java:281)
    at org.apache.http.impl.conn.LoggingSessionInputBuffer.readLine(LoggingSessionInputBuffer.java:115)
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:92)
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:61)
    at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:254)
    at org.apache.http.impl.AbstractHttpClientConnection.receiveResponseHeader(AbstractHttpClientConnection.java:289)
    at org.apache.http.impl.conn.DefaultClientConnection.receiveResponseHeader(DefaultClientConnection.java:252)
    at org.apache.http.impl.conn.ManagedClientConnectionImpl.receiveResponseHeader(ManagedClientConnectionImpl.java:191)
    at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:300)
    at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:127)
    at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:715)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:520)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:906)
    at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:137)
    at org.apache.http.impl.client.DecompressingHttpClient.execute(DecompressingHttpClient.java:118)
    at org.apache.jena.riot.web.HttpOp.exec(HttpOp.java:1109)
    at org.apache.jena.riot.web.HttpOp.execHttpGet(HttpOp.java:384)
    at org.apache.jena.riot.web.HttpOp.execHttpGet(HttpOp.java:446)
    at com.hp.hpl.jena.sparql.engine.http.HttpQuery.execGet(HttpQuery.java:346)
    ... 94 more

我在这一行收到错误:

ResultSet results1 = ResultSetFactory.copyResults(exec1.execSelect());

我注意到在完成多次查询后出现此错误。为什么我会收到此错误？

Answer 1

当您不关闭资源时，这种情况经常发生(我敢打赌这就是您的情况的原因)。首先，例如您的 results1 未关闭。

另一件事是，即使您将 exec1.close(); 放在方法末尾，成像异常也会在您的 //DO SOMETHING 代码中弹出。在这种情况下，您的 exec1 会被关闭吗？正确答案是否定的。正是finally block 是专为.因此，将与关闭资源相关的所有代码放在finally block 中，应该没问题。

注意，如果您使用 jdk 7+，您也可以使用 the try-with-resources Statement 以更优雅的方式完成此操作。

希望有帮助