如何拦截线程生命周期？

Question

可以在创建线程时记录.我们需要一个自定义ThreadFactory实现,从中创建所有线程,并从newThread我们可以记录的方法.但是如果我们需要记录线程被销毁和删除的时候我们怎么做呢？

import java.util.concurrent.ThreadFactory;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.log4j.Logger;

public enum MyThreadFactory implements ThreadFactory {
    INSTANCE;

    private final AtomicInteger poolNumber = new AtomicInteger(1);
    private final Logger logger = Logger.getLogger(getClass());
    private final ThreadGroup threadGroup;
    private final AtomicInteger threadNumber = new AtomicInteger(1);
    private final String namePrefix;

    private RpiThreadFactory() {
        SecurityManager securityManager = System.getSecurityManager();
        threadGroup = (securityManager != null) ? securityManager.getThreadGroup() : Thread.currentThread().getThreadGroup();
        namePrefix = "RpiPool-" + poolNumber.getAndIncrement() + "-Thread-";

    }

    public Thread newThread(Runnable runnable) {
        Thread thread = new Thread(threadGroup, runnable, namePrefix + threadNumber.getAndIncrement(), 0);
        thread.setPriority(Thread.NORM_PRIORITY);
        thread.setUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {

            public void uncaughtException(Thread thread, Throwable cause) {
                logger.error(cause.getMessage(), cause);
            }
        });

        logger.debug(thread.toString() + " created.");
        return thread;
    }
}

Answer 1

由于您已经在实现自己的线程工厂,因此一种方法是将runnable包装到另一个可在作业启动和完成时记录的runnable中.像这样:

 public Thread newThread(Runnable runnable) {
     Runnable wrapper = new Runnable() {

        @Override
        public void run() {
            System.out.println("Starting thread ...");
            try {
                runnable.run();
                System.out.println("Thread done");
            } catch (Throwable t) {
                System.out.println("Thread exited abnormally");
                // Log exception
            }

        }

     };
     Thread thread = new Thread(threadGroup, wrapper, namePrefix + threadNumber.getAndIncrement(), 0);
    // ...
}

这不记录实际的线程生命周期,但与例如信任终结器在线程被销毁时进行记录相比,它是可靠的.

替换System.out.println为您选择的日志记录调用.