tomcat线程数

小灰灰 2022-07-13 12:55 163阅读 0赞

测试tomcat线程数：

启用的协议是apr协议。因为我用了executor属性，官方文档中对Connector标签中的executor属性是这么说的：

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   <td align="left" style="border-collapse:separate"> <p style="border-collapse:separate">A reference to the name in an&nbsp;<a href="http://tomcat.apache.org/tomcat-7.0-doc/config/executor.html" style="border-collapse:separate" rel="nofollow">Executor</a>&nbsp;element. If this attribute is set, and the named executor exists, the connector will use the executor, and all the other thread attributes will be ignored. Note that if a shared executor is not specified for a connector then the connector will use a private, internal executor to provide the thread pool.</p> </td> 
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如果用了executor属性，那么所有其他的thread的属性将会被忽略。所以此时我们只有看Executor标签，来设置executor标签中的属性：

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   <td align="left" style="border-collapse:separate"><code style="background-color:transparent; padding:0px 0.1em; border-collapse:separate">maxThreads</code></td> 
   <td align="left" style="border-collapse:separate"> <p style="border-collapse:separate">(int) The max number of active threads in this pool, default is&nbsp;<code style="background-color:rgb(224,255,255); padding:0px 0.1em; border-collapse:separate">200</code></p> </td> 
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   <td align="left" style="border-collapse:separate"><code style="background-color:transparent; padding:0px 0.1em; border-collapse:separate">minSpareThreads</code></td> 
   <td align="left" style="border-collapse:separate"> <p style="border-collapse:separate">(int) The minimum number of threads always kept alive, default is&nbsp;<code style="background-color:rgb(224,255,255); padding:0px 0.1em; border-collapse:separate">25</code></p> </td> 
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   <td align="left" style="border-collapse:separate"><code style="background-color:transparent; padding:0px 0.1em; border-collapse:separate">maxQueueSize</code></td> 
   <td align="left" style="border-collapse:separate"> <p style="border-collapse:separate">(int) The maximum number of runnable tasks that can queue up awaiting execution before we reject them. Default value is&nbsp;<code style="background-color:rgb(224,255,255); padding:0px 0.1em; border-collapse:separate">Integer.MAX_VALUE</code></p> </td> 
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如果我的executor标签中不设置maxQueneSize属性，那么默认的为int的最大值，意思就是：如果我不设置这个，那么请求数在达到Integer.MAX\_VALUE之前是不会被拒绝的，都会放在队列里面等待执行。

如果我按照上面的配置，最小存活数是1，最大活跃线程数是2，队列里面最大是1，那么当我们重启tomcat的时候，第一次去请求会发现一共只有3个请求线程被执行（2+1），剩下的请求都会被tomcat直接reject拒绝掉，如果你去捕获异常，会发现抛出如下错误：

警告: Socket processing request was rejected for:469001312  
java.util.concurrent.RejectedExecutionException: Work queue full.  
at org.apache.catalina.core.StandardThreadExecutor.execute(StandardThreadExecutor.java:172)  
at org.apache.tomcat.util.net.AprEndpoint.processSocketWithOptions(AprEndpoint.java:882)  
at org.apache.tomcat.util.net.AprEndpoint$Acceptor.run(AprEndpoint.java:1088)  
at java.lang.Thread.run(Thread.java:745)  
  
  
一月 10, 2017 2:59:34 下午 org.apache.tomcat.util.net.AprEndpoint processSocket  
警告: Socket processing request was rejected for:468993104  
java.util.concurrent.RejectedExecutionException: Work queue full.  
at org.apache.catalina.core.StandardThreadExecutor.execute(StandardThreadExecutor.java:172)  
at org.apache.tomcat.util.net.AprEndpoint.processSocket(AprEndpoint.java:913)  
at org.apache.tomcat.util.net.AprEndpoint$Poller.run(AprEndpoint.java:1973)  
at java.lang.Thread.run(Thread.java:745)  
socket请求被拒绝，直接返回502错误。

当我们再次用多线程去请求的时候，发现此时就不一定只有3个线程可用了，会发现基本上都会大于3个？（why）