是什么原因造成java.util.logging.SimpleFormatter.format線程塊？

Question

我的項目使用log4j，但這似乎被java.util.logging阻止了。 Java信息：Java版本“ 1.8.0_121” Java SE運行時環境（內部版本1.8.0_121-b13）Java HotSpot™64位服務器VM（內部版本25.121-b13，混合模式）

服務器是tomcat。

Jstack日志如下：

"http-nio-192.168.0.94-8443-exec-316" #378 daemon prio=5 os_prio=0 tid=0x00007f96d4f42800 nid=0x3466 waiting for monitor entry [0x00007f96c753d000]
       java.lang.Thread.State: BLOCKED (on object monitor)
            at java.util.logging.SimpleFormatter.format(SimpleFormatter.java)
            - waiting to lock <0x00000006c53cdae0> (a java.util.logging.SimpleFormatter)
            at org.apache.juli.FileHandler.publish(FileHandler.java:197)
            at java.util.logging.Logger.log(Logger.java:738)
            at java.util.logging.Logger.doLog(Logger.java:765)
            at java.util.logging.Logger.log(Logger.java:788)
            at org.restlet.engine.log.LogFilter.afterHandle(LogFilter.java:106)
            at org.restlet.routing.Filter.handle(Filter.java:208)
            at org.restlet.engine.CompositeHelper.handle(CompositeHelper.java:211)
            at org.restlet.Component.handle(Component.java:406)
            at org.restlet.Server.handle(Server.java:516)
            at org.restlet.engine.connector.ServerHelper.handle(ServerHelper.java:72)
            at org.restlet.engine.adapter.HttpServerHelper.handle(HttpServerHelper.java:152)
            at org.restlet.ext.servlet.ServerServlet.service(ServerServlet.java:1118)
            at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at com.xxx.xxx.web.Filter.xxxxxxx.doFilter(SGRequestCheck.java:129)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at com.xxx.trace.http.servlet.filter.BraveServletFilter.doFilter(BraveServletFilter.java:165)
            at com.xxx.trace.http.servlet.filter.TraceServletFilter.doFilter(TraceServletFilter.java:73)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:218)
            at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
            at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
            at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
            at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
            at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
            at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
            at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
            at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
            at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1756)
            at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1715)
            - locked <0x00000006c8a84a70> (a org.apache.tomcat.util.net.SecureNioChannel)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
            at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
            at java.lang.Thread.run(Thread.java:745)

       Locked ownable synchronizers:
            - <0x00000006c9f790b0> (a java.util.concurrent.ThreadPoolExecutor$Worker)

Answer 1

阻塞狀態並不總是意味着發生了不好的事情，它只是說某個線程正在等待另一個線程釋放其鎖以獲取監視器鎖。 在您的情況下，多個線程共享SimpleFormatter類的同一實例，該實例在調用format方法時獲得一個鎖。

public synchronized String format(LogRecord record)