Question

我的应用程序在runnnig运行一段时间后陷入死锁。我接受了一个线程转储并注意到我的所有应用程序线程都留下了一个状态

"APP-Thread-20" prio=6 tid=0x0000000007414800 nid=0x1268 waiting on condition [0x000000000951f000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.$$YJP$$park(Native Method)
    - parking to wait for  <0x00000000e0179568> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at sun.misc.Unsafe.park(Unsafe.java)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
    at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:947)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
    at java.lang.Thread.run(Thread.java:662)

   Locked ownable synchronizers:
    - None

处于runnable状态的唯一线程卡在使用SAX Parser的代码上。该线程转储如下所示

"APP-Thread-19" prio=6 tid=0x0000000007413800 nid=0x18b4 runnable [0x00000000094de000]
   java.lang.Thread.State: RUNNABLE
    at java.net.SocketInputStream.$$YJP$$socketRead0(Native Method)
    at java.net.SocketInputStream.socketRead0(SocketInputStream.java)
    at java.net.SocketInputStream.read(SocketInputStream.java:129)
    at java.io.BufferedInputStream.fill(BufferedInputStream.java:218)
    at java.io.BufferedInputStream.read1(BufferedInputStream.java:258)
    at java.io.BufferedInputStream.read(BufferedInputStream.java:317)
    - locked <0x00000000e2f3fee8> (a java.io.BufferedInputStream)
    at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:697)
    at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:640)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1195)
    - locked <0x00000000e2f3ff90> (a sun.net.www.protocol.http.HttpURLConnection)
    at org.apache.xerces.impl.XMLEntityManager.setupCurrentEntity(Unknown Source)
    at org.apache.xerces.impl.XMLEntityManager.startEntity(Unknown Source)
    at org.apache.xerces.impl.XMLEntityManager.startEntity(Unknown Source)
    at org.apache.xerces.impl.XMLDTDScannerImpl.startPE(Unknown Source)
    at org.apache.xerces.impl.XMLDTDScannerImpl.skipSeparator(Unknown Source)
    at org.apache.xerces.impl.XMLDTDScannerImpl.scanDecls(Unknown Source)
    at org.apache.xerces.impl.XMLDTDScannerImpl.scanDTDExternalSubset(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentScannerImpl$DTDDispatcher.dispatch(Unknown Source)
    at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
    at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
    at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.SAXParserImpl$JAXPSAXParser.parse(Unknown Source)
    at org.apache.xerces.jaxp.SAXParserImpl.parse(Unknown Source)
    at javax.xml.parsers.SAXParser.parse(SAXParser.java:198)
    at com.test.Parser.Parser.parseDocument(Parser.java:33)
    at com.test.processor.LinkExtractor.extractLinksFromXml(LinkExtractor.java:222)
    at com.test.processor.LinkExtractor.process(LinkExtractor.java:102)
    at com.test.content.pipeline.PipelineProcessingTask.run(PipelineProcessingTask.java:76)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:441)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

   Locked ownable synchronizers:
    - <0x00000000e017c3b8> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)

所有线程都在处理一系列任务，其中解析只是其中一项任务。解析代码不同步，每个线程都在执行一个新的Parser（）。parse（）。

这个问题是否以SAXParser为中心？还是我看错了方向？

我有3个线程转储，并且在所有3个场景中都是相同的。

这是解析的代码。请求是一个httpMethod。

byte[] data = IOUtils.toByteArray(req.getResponseBodyAsStream());
body = new String(data,"UTF-8").trim();
Parser parser = new Parser();
List<String> entries = parser.parseDocument(response);

Answer 1

您的解析器正在等待来自网络的输入，而它正在阻止所有其他线程。

Answer 2

因此，您的应用程序中没有死锁。

队列中没有任务。所以除了一个人之外的所有工人都在等待一些任务进入队列。

一位执行人员加载XML源以通过SAX解析。看起来这是一个缓慢的操作。可能XML很大或网络速度很慢。

环境问题。在某些原因，没有人将任务放入队列。还要检查通过网络加载XML的性能。

应用程序陷入僵局

2 个答案: