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[英]Tomcat webapp error - application started thread [AWT-Windows] but has failed to stop it - memory leak?
[英]Servlet “has started a thread but failed to stop it” - memory leak in Tomcat
Apache Tomcat多次說:
Web應用程序[/ MyServlet]似乎已啟動名為[pool-61-thread-2]的線程,但未能將其停止。 這很可能造成內存泄漏。
這有危險嗎? servlet應該能夠處理10.000個請求/天。 完成后如何關閉線程?
class Worker {
private final CountDownLatch startSignal;
private final CountDownLatch doneSignal;
private final int threadNumber;
Worker(
CountDownLatch startSignal,
CountDownLatch doneSignal,
int threadNumber
){
this.startSignal = startSignal;
this.doneSignal = doneSignal;
this.threadNumber = threadNumber;
}
public String[][] getSomeStrArrArr() {
String[][] isRs = new String[8][20];
String[][] inRs = new String[8][20];
String[][] iwRs = new String[8][20];
try {
startSignal.await();
if (threadNumber == 1) {
// get String[][] result for thread number 1
isRs = getIS(erg1, erg2, request);
}
if (threadNumber == 2) {
// get String[][] result for thread number 2
inRs = getIN(search_plz, request);
}
if (threadNumber == 3) {
// get String[][] result for thread number 3
iwRs = getIW(erg1, erg2, request);
}
doneSignal.countDown();
} catch (InterruptedException ex) {
System.out.println(
"Thread number "+threadNumber+" has been interrupted."
);
}
if (threadNumber == 1) {
return isRs;
}
if (threadNumber == 2) {
return inRs;
}
if (threadNumber == 3) {
return iwRs;
}
return null;
}
public Callable<String[][]> getSomeCallableStrArrArr(){
return new Callable<String[][]>() {
public String[][] call() throws Exception {
return getSomeStrArrArr();
}
};
}
}
ExecutorService pool = Executors.newFixedThreadPool(3);
Set<Future<String[][]>> set = new HashSet<Future<String[][]>>();
CountDownLatch startSignal = new CountDownLatch(1);
CountDownLatch doneSignal = new CountDownLatch(3);
for (int i=1;i<=3;i++) {
Worker worker = new Worker(startSignal,doneSignal,i);
Callable<String[][]> callable =
worker.getSomeCallableStrArrArr();
Future<String[][]> future = pool.submit(callable);
set.add(future);
}
startSignal.countDown();
try {
doneSignal.await();
是的,這是一個問題。 如果您的代碼啟動非守護程序線程,那么這些線程將繼續工作,直到它們退出其run方法。 即使其他一切都完成了,舊的JVM也會在這些線程繼續運行的時候徘徊。 如果啟動一個新實例,那么您可能會遇到舊線程仍在與新實例創建的線程一起工作的情況。
需要設計任務,以便他們能夠響應中斷(而不是吃異常並繼續進行,這就是你的例子所示)。 這意味着檢查當前線程上的中斷標志,並以有用的方式捕獲InterruptedException,允許任務中斷其工作,並在需要時重置中斷的標志。 ExecutorService實現有一個shutdownNow方法,它將中斷當前任務。
確保執行程序關閉, 您可以在ServletContextListener中處理它 。
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