Java线程池 - ThreadFactory封装

• 自定义ThreadFactory，便于创建自定义线程
• 自定义ThreadGroup，便于对线程分组管理

  ThreadFactory和ThreadGroup封装

  @Slf4j
  public class CustomThreadFactory implements ThreadFactory {
      private AtomicInteger threadNum = new AtomicInteger(1);
      private final static String prefix = "Custom-thread-";
  
      @Override
      public Thread newThread(Runnable r) {
          String name = prefix + threadNum.getAndIncrement();
          ThreadGroup threadGroup = new CustomThreadGroup("Custom_GROUP");
          //非守护进程
          threadGroup.setDaemon(false);
          //优先执行
          threadGroup.setMaxPriority(Thread.MAX_PRIORITY);
  
          Thread thread = new Thread(threadGroup, r, name);
          return thread;
      }
  
  
      static class CustomThreadGroup extends ThreadGroup {
  
          public CustomThreadGroup(String name) {
              super(name);
          }
  
          public CustomThreadGroup(ThreadGroup parent, String name) {
              super(parent, name);
          }
  
          /**
           * 异常处理
           *
           * @param t
           * @param e
           */
          @Override
          public void uncaughtException(Thread t, Throwable e) {
              log.error("线程名称:{},异常信息:{},异常栈:{}",
                      t.getName(), e.getMessage(), e);
          }
      }
  }

ThreadFactory

• ThreadFactory的作用就是提供创建线程的功能的线程工厂
• 它是通过newThread()提供创建线程
• newThread()创建的线程对应的任务是Runnable对象
• 它创建的线程默认都是“非守护线程”而且“线程优先级都是Thread.NORM_PRIORITY”。

ThreadGroup

• 方便地对加入这个线程组的多个线程进行操作。
• 重写uncaughtException()来实现自己的线程运行时异常处理逻辑
• 线程组可以进行复制，快速定位到一个线程
• Thread类的enumerate()方法用于将每个活动线程的线程组及其子组复制到指定的数组中

  ThreadGroup group = Thread.currentThread().getThreadGroup();  
  ThreadGroup topGroup = group;  
  // 遍历线程组树，获取根线程组  
  while (group != null) {  
      topGroup = group;  
      group = group.getParent();  
  }  
  Thread[] slackList = new Thread[topGroup.activeCount() ];  
  // 获取根线程组的所有线程  
  int actualSize = topGroup.enumerate(slackList);  
  // copy into a list that is the exact size  
  Thread[] list = new Thread[actualSize];  
  System.arraycopy(slackList, 0, list, 0, actualSize);  
  System.out.println("Thread list size == " + list.length);  
  for (Thread thread : list) {  
      System.out.println(thread.getName());  
  }