如何正确地停止Java中的线程?

问题:

我需要一个解决方案来正确地停止Java中的线程。
我有IndexProcessor类实现Runnable接口:

public class IndexProcessor implements Runnable {

    private static final Logger LOGGER = LoggerFactory.getLogger(IndexProcessor.class);

    @Override
    public void run() {
        boolean run = true;
        while (run) {
            try {
                LOGGER.debug("Sleeping...");
                Thread.sleep((long) 15000);

                LOGGER.debug("Processing");
            } catch (InterruptedException e) {
                LOGGER.error("Exception", e);
                run = false;
            }
        }

    }
}

我有ServletContextListener类启动和停止线程:

public class SearchEngineContextListener implements ServletContextListener {

    private static final Logger LOGGER = LoggerFactory.getLogger(SearchEngineContextListener.class);

    private Thread thread = null;

    @Override
    public void contextInitialized(ServletContextEvent event) {
        thread = new Thread(new IndexProcessor());
        LOGGER.debug("Starting thread: " + thread);
        thread.start();
        LOGGER.debug("Background process successfully started.");
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        LOGGER.debug("Stopping thread: " + thread);
        if (thread != null) {
            thread.interrupt();
            LOGGER.debug("Thread successfully stopped.");
        }
    }
}

但是当我关闭tomcat时,我的IndexProcessor类中有异常:

2012-06-09 17:04:50,671 [Thread-3] ERROR  IndexProcessor Exception
java.lang.InterruptedException: sleep interrupted
    at java.lang.Thread.sleep(Native Method)
    at lt.ccl.searchengine.processor.IndexProcessor.run(IndexProcessor.java:22)
    at java.lang.Thread.run(Unknown Source)

我正在使用JDK 1.6。所以问题是:
我如何停止线程,不会抛出任何异常?
 附:我不想使用.stop();方法,因为它已被弃用。

回答:

IndexProcessor类中,您需要一种设置标志的方式,通知线程需要终止,类似于您在类范围中使用的变量run
当你想停止线程时,你设置这个标志,并在线程上调用join()等待它完成。
通过使用volatile变量或使用与用作标志的变量同步的getter和setter方法,确保该标志是线程安全的。

public class IndexProcessor implements Runnable {

    private static final Logger LOGGER = LoggerFactory.getLogger(IndexProcessor.class);
    private volatile boolean running = true;

    public void terminate() {
        running = false;
    }

    @Override
    public void run() {
        while (running) {
            try {
                LOGGER.debug("Sleeping...");
                Thread.sleep((long) 15000);

                LOGGER.debug("Processing");
            } catch (InterruptedException e) {
                LOGGER.error("Exception", e);
                running = false;
            }
        }

    }
}

然后在SearchEngineContextListener

public class SearchEngineContextListener implements ServletContextListener {

    private static final Logger LOGGER = LoggerFactory.getLogger(SearchEngineContextListener.class);

    private Thread thread = null;
    private IndexProcessor runnable = null;

    @Override
    public void contextInitialized(ServletContextEvent event) {
        runnable = new IndexProcessor();
        thread = new Thread(runnable);
        LOGGER.debug("Starting thread: " + thread);
        thread.start();
        LOGGER.debug("Background process successfully started.");
    }

    @Override
    public void contextDestroyed(ServletContextEvent event) {
        LOGGER.debug("Stopping thread: " + thread);
        if (thread != null) {
            runnable.terminate();
            thread.join();
            LOGGER.debug("Thread successfully stopped.");
        }
    }
}

 
 
Code问答: http://codewenda.com/topics/python/
Stackoverflow: How to properly stop the Thread in Java?

*转载请注明本文链接以及stackoverflow的英文链接

发表评论

电子邮件地址不会被公开。 必填项已用*标注

1 + 1 =