在Tomcat中運行後臺Java程序

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; 
    } 
}

你必須上下文監聽器添加到你的web.xml，在這裏你還可以指定你想運行的線程數量後臺作業：

<listener> 
    <listener-class>com.example.ExecutorContextListener</listener-class> 
    </listener>

您可以從你的servlet訪問執行程序和作業提交到它：

ExecutorService executor = (ExecutorService)getServletContext().getAttribute("MY_EXECUTOR"); 
... 
executor.submit(myJob);

如果你使用Spring，這一切大概可以還送simpler

來源

2011-02-05 16:24:58 nos

在Tomcat中運行後臺Java程序

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