任何人都可以在这里提供建议吗？我有一种情况，用户将通过Java JSP和servlet以交互方式将数据挖掘请求提交给我的应用程序，该应用程序将动态地制定数据等的关联规则。
由于这样的工作可能需要一段时间，我正在考虑在服务器上进行某种过程以在后台运行此类请求，因此它不会“锁定”会话，并且可能使用大量服务器内存来损害系统。
由于该系统由一系列Java JSP和servlet组成，这些Java JSP和servlet在MySQL数据库的Tomcat容器中运行，任何人都可以建议前进的道路吗？
谢谢
摩根先生
使用执行器服务。
但是，您应该做一些事情，将线程标记为守护进程线程，以便它至少在错误情况下不会占用tomcat，并且您应该在servlet上下文被破坏时停止执行器（例如，当您重新部署或停止应用程序时）。为此，请使用 ServletContextListener：
public class ExecutorContextListener implements ServletContextListener {
private ExecutorService executor;
public void contextInitialized(ServletContextEvent arg0) {
ServletContext context = arg0.getServletContext();
int nr_executors = 1;
ThreadFactory daemonFactory = new DaemonThreadFactory();
try {
nr_executors = Integer.parseInt(context.getInitParameter("nr-executors"));
} catch (NumberFormatException ignore ) {}
if(nr_executors <= 1) {
executor = Executors.newSingleThreadExecutor(daemonFactory);
} else {
executor = Executors.newFixedThreadPool(nr_executors,daemonFactory);
}
context.setAttribute("MY_EXECUTOR", executor);
}
public void contextDestroyed(ServletContextEvent arg0) {
ServletContext context = arg0.getServletContext();
executor.shutdownNow(); // or process/wait until all pending jobs are done
}
}
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;
/**
* Hands out threads from the wrapped threadfactory with setDeamon(true), so the
* threads won't keep the JVM alive when it should otherwise exit.
*/
public class DaemonThreadFactory implements ThreadFactory {
private final ThreadFactory factory;
/**
* Construct a ThreadFactory with setDeamon(true) using
* Executors.defaultThreadFactory()
*/
public DaemonThreadFactory() {
this(Executors.defaultThreadFactory());
}
/**
* Construct a ThreadFactory with setDeamon(true) wrapping the given factory
*
* @param thread
* factory to wrap
*/
public DaemonThreadFactory(ThreadFactory factory) {
if (factory == null)
throw new NullPointerException("factory cannot be null");
this.factory = factory;
}
public Thread newThread(Runnable r) {
final Thread t = factory.newThread(r);
t.setDaemon(true);
return t;
}
}
您必须将上下文侦听器添加到 Web.xml，还可以在其中指定要运行后台作业的线程数：
<listener>
<listener-class>com.example.ExecutorContextListener</listener-class>
</listener>
您可以从 servlet 访问执行器并向其提交作业：
ExecutorService executor = (ExecutorService )getServletContext().getAttribute("MY_EXECUTOR");
...
executor.submit(myJob);
如果你正在使用Spring，所有这些都可以变得更加简单。
