Java并发25 ThreadFactory使用的必要性

1.阿里编码规约扫描插件的友善提醒

当我们构建一个线程池时，如果使用了阿里的编码规范扫描插件的话，会提醒我们要使用带ThreadFactory参数的ThreadPoolExecutor构造方法，Ctrl+F1进去我们会看到：
之前的文章已经介绍了线程池中ThreadFactory用于设置创建线程工厂，通过线程工厂给每个创建出来的线程设置更有意义的名字，这样就如插件提示的那样 出错时方便问题的回溯 ，所有当我们在创建线程池的时候使用带有ThreadFactory参数的构造方法是非常有必要的。

2.ThreadFactory的使用

关于ThreadFactory我们可以guava提供的ThreadFactoryBuilder，也可以自定义。这里两种方式各举一个例子：

	package cc.mynatapp.detroitdentist.current;

import com.google.common.util.concurrent.ThreadFactoryBuilder;

import java.util.concurrent.*;

/**
* @author Xu hao
* @Description ThreadFactory的使用
* @Version 1.0
* Email [email protected]
* create on 2019/4/15
*/
public class UseThreadFactory {

   private static ThreadFactory namedFactory = new ThreadFactoryBuilder().setNameFormat("线程-demo-%d").build();

   private static ThreadPoolExecutor pool = new ThreadPoolExecutor(2, 4, 60, TimeUnit.SECONDS, new
           ArrayBlockingQueue<>(10), namedFactory, new ThreadPoolExecutor.AbortPolicy());

   public static void main(String[] args) {
       for (int i = 1; i <= 14; i++) {
           Callable<Boolean> task = createTask(i);
           pool.submit(task);
           System.out.println("after task:" + i + " submitted, current active count: "
                   + pool.getActiveCount() + ", size of queue: " + pool.getQueue().size());
       }
       pool.shutdown();
   }

   /**
    * @Author Xu hao
    * @Description 创建任务
    * @Date 2019/3/19 0:08
    * @param i
    * @return java.util.concurrent.Callable
    **/
   private static Callable<Boolean> createTask(int i){

       Callable<Boolean> callable = () -> {
           TimeUnit.SECONDS.sleep(10);
           System.out.println("thread: " + Thread.currentThread().getName() + " execute task: " + i);
           return true;
       };

       return callable;
   }
}

当然，我们也可以自定义ThreadFactory，举例如下：

package cc.mynatapp.detroitdentist.current;

import com.google.common.util.concurrent.ThreadFactoryBuilder;

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

/**
* @author Xu hao
* @Description ThreadFactory的使用
* @Version 1.0
* Email [email protected]
* create on 2019/4/15
*/
public class UseThreadFactory {

   /**
    * 自定义ThreadFactory
    **/
   private static ThreadFactory namedFactory = nameThreadFactory();

   private static ThreadPoolExecutor pool = new ThreadPoolExecutor(2, 4, 60, TimeUnit.SECONDS, new
           ArrayBlockingQueue<>(10), namedFactory, new ThreadPoolExecutor.AbortPolicy());

   public static void main(String[] args) {
       for (int i = 1; i <= 14; i++) {
           Callable<Boolean> task = createTask(i);
           pool.submit(task);
           System.out.println("after task:" + i + " submitted, current active count: "
                   + pool.getActiveCount() + ", size of queue: " + pool.getQueue().size());
       }
       pool.shutdown();
   }

   /**
    * @Author Xu hao
    * @Description 创建任务
    * @Date 2019/3/19 0:08
    * @param i
    * @return java.util.concurrent.Callable
    **/
   private static Callable<Boolean> createTask(int i){

       Callable<Boolean> callable = () -> {
           TimeUnit.SECONDS.sleep(10);
           System.out.println("thread: " + Thread.currentThread().getName() + " execute task: " + i);
           return true;
       };

       return callable;
   }

   /**
    * @Author Xu hao
    * @Description 自定义ThreadFactory
    * @Date 2019/4/19 23:28
    * @param
    * @return java.util.concurrent.ThreadFactory
    **/
   private static ThreadFactory nameThreadFactory(){
       AtomicInteger tag = new AtomicInteger(1);
       ThreadFactory factory = (Runnable r) -> {
           Thread thread = new Thread(r);
           thread.setName("线程-demo-" + tag.getAndIncrement());
           return thread;
       };

       return factory;
   }

}

运行上面两种方法的举例都可以得到如下日志输出，我们可以看到线程池中的线程被命名为“线程-demo-%d”了