昨天短信服務又宕機了，jstack打出線程信息發現 所有線程池的線程都在wait，棧信息如下：

at java.lang.Object.wait(Native Method)
- waiting on [0x000000070754fb60] (a org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$ConnectionPool)
at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.doGetConnection(MultiThreadedHttpConnectionManager.java:518)
- locked [0x000000070754fb60] (a org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$ConnectionPool)
at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager.getConnectionWithTimeout(MultiThreadedHttpConnectionManager.java:416)
at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:153)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
at com.dhf.sms.util.HttpUtil.getHtml(HttpUtil.java:75)
at com.dhf.sms.core.impl.MDSmsserviceImpl.send(MDSmsserviceImpl.java:165)
at com.dhf.sms.core.SmsTask.run(SmsTask.java:156)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at com.kuaidadi.framework.thread.bean.TaxiFutureTask.run(TaxiFutureTask.java:48)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

?

發現所有線程都卡在MultiThreadedHttpConnectionManager 的doGetConnection方法：

? hostPool.waitingThreads.addLast(waitingThread);connectionPool.waitingThreads.addLast(waitingThread);connectionPool.wait(timeToWait);//卡在這

查看代碼和google，發現應該是connection連接未釋放的問題的。如果不調用getMethod.getResponseBodyAsString()，就不會釋放connection。并且我們沒有指定maxConnectionsPerHost，默認為2，所以當以下代碼在第16行拋出exception后連接不會被釋放掉，一旦發生兩次，那么僅有的2個connection都被占用，新進來的線程就卡住了。

1 public static String getHtml(String url,String charSet,Integer channelId) throws IOException, SmsHttpStatusException { 2 StaticLogInfo staticLogInfo = new StaticLogInfo(); 3 staticLogInfo.setCmd("Channel "+channelId+"("+getHost(url)+")"); 4 GetMethod getMethod = null; 5 try { 6 if (StringUtils.isBlank(charSet)) { 7 charSet = SmsConstant.DEFAULT_CHARSET; 8 } 9 10 getMethod = new GetMethod(url); 11 int statusCode = httpClient.executeMethod(getMethod); 12 if (statusCode != HttpStatus.SC_OK 13 && statusCode != HttpStatus.SC_MOVED_PERMANENTLY 14 && statusCode != HttpStatus.SC_MOVED_TEMPORARILY) { 15 log.error("statusCode:" + statusCode + " url請求失敗========>" + url); 16 throw new SmsHttpStatusException("請求失敗"); 17 } 18 19 String responseBody = new String(getMethod.getResponseBodyAsString().getBytes(charSet),SmsConstant.DEFAULT_CHARSET); 20 return responseBody; 21 } catch (IOException e) { 22 staticLogInfo.setResultCode("1"); 23 throw e; 24 } catch (SmsHttpStatusException e) { 25 staticLogInfo.setResultCode("1"); 26 throw e; 27 } finally { 28 29 reqLogger.info(staticLogInfo); 30 } 31 } 32

?

?

解決辦法是在finally里釋放connection：

finally {if(getMethod!=null){getMethod.releaseConnection();}reqLogger.info(staticLogInfo);}

并且增加最大連接數：

httpConnectionManagerParams.setMaxTotalConnections(100);httpConnectionManagerParams.setDefaultMaxConnectionsPerHost(20);

?

參考：http://blog.csdn.net/xiaojianpitt/article/details/7818971

轉載于:https://www.cnblogs.com/longzhaoyu/p/4563513.html

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