怎么写一个高效稳定的缓存队列？

[miracleliu]

我写了一个，大家给点意见

队列和executor

public class SyncQueue {

	public static final ExecutorService executorService = Executors.newFixedThreadPool(10);

	public static final BlockingQueue<String> queue = new ArrayBlockingQueue<String>(200);

	public static final Deque<String> dq = new LinkedBlockingDeque<String>(10);
	//	public static boolean addjob(String jsonData) {
	//		return queue.offer(jsonData);
	//	}
}

servlet，接受请求

public class Clean extends HttpServlet {
	private static final long serialVersionUID = 1L;

	private static Logger log = Logger.getLogger(Clean.class);

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		String jsonData = request.getParameter("json");

		if (jsonData != null && !jsonData.equals("")) {

			if (SyncQueue.queue.offer(jsonData)) {//添加到缓存队列
				SyncQueue.executorService.execute(new DealThread());//调用线程执行
				log.info("ok," + jsonData);
				response.sendError(HttpServletResponse.SC_OK);
			} else {
				log.info("full   !!!!!!!!!!!!!!!!!!!!!!!!!!!!!" + jsonData);
				response.sendError(HttpServletResponse.SC_TEMPORARY_REDIRECT);
			}
		} else {
			log.info("wrong param" + jsonData);
			response.sendError(HttpServletResponse.SC_BAD_REQUEST);
		}

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		this.doGet(request, response);
	}

}

处理线程

public class DealThread implements Runnable {

	private static Logger log = Logger.getLogger(DealThread.class);

	private String name = "";

	public DealThread() {
	}

	public DealThread(String name) {
		this.name = name;
	}

	@Override
	public void run() {

		String json = SyncQueue.queue.poll();
		if (json != null) {
			log.info("josn:" + json);
			long start = System.currentTimeMillis();
			Connection conn = DBPool.getInstance().getConnection("live");
			PreparedStatement pstmt = null;
			ResultSet rs = null;
			try {
				pstmt = conn.prepareStatement("select * from channel where id=?");
				pstmt.setInt(1, Integer.parseInt(json));
				rs = pstmt.executeQuery();
				while (rs.next()) {
					log.info("thread," + Thread.currentThread().getName() + ":" + rs.getString("channelName"));
				}
				Thread.sleep(new Random().nextInt(4000));//for test模拟大任务
			} catch (SQLException e) {
				retry(json);
				log.error(" sql exception ;", e);
			} catch (InterruptedException e) {
				retry(json);
				log.error(" interrupted; ", e);
			} finally {
				DBPool.close(pstmt, rs, conn);
			}
			long exeTime = System.currentTimeMillis() - start;
			log.info("thread," + Thread.currentThread().getName() + ":" + exeTime + "ms");
		}
	}

	private void retry(String json) {
Connection conn = DBPool.getInstance().getConnection("live");
			PreparedStatement pstmt = null;
			ResultSet rs = null;
			try {
				pstmt = conn.prepareStatement("select * from channel where id=?");
				pstmt.setInt(1, Integer.parseInt(json));
				rs = pstmt.executeQuery();
				while (rs.next()) {
					log.info("thread," + Thread.currentThread().getName() + ":" + rs.getString("channelName"));
				}
				Thread.sleep(new Random().nextInt(4000));//for test模拟大任务
			} catch (SQLException e) {
				log.error(" sql exception ;", e);
			} catch (InterruptedException e) {
				log.error(" interrupted; ", e);
			} finally {
				DBPool.close(pstmt, rs, conn);
			}
	}

}

[miracleliu]

引用 2 楼 bao110908 的回复:

感觉直接使用线程池就好了，没看出来这里使用队列的意义在哪？

直接用线程池的话， 如果线程池处理不过来，怎么通知客户端，说已经满了处理不过来了？

[赵增光]

不管是否能用的上，想说分享就是一种美德。

[火龙果被占用了]

引用 5 楼 miraclestar 的回复:

[quote=引用 2 楼 bao110908 的回复:] 感觉直接使用线程池就好了，没看出来这里使用队列的意义在哪？

直接用线程池的话， 如果线程池处理不过来，怎么通知客户端，说已经满了处理不过来了？[/quote] ThreadPoolExecutor 类不是可以使用相关的 RejectedExecutionHandler 接口么？默认的是 AbortPolicy 实现，即抛出异常。

[miracleliu]

引用 7 楼 bao110908 的回复:

[quote=引用 5 楼 miraclestar 的回复:] [quote=引用 2 楼 bao110908 的回复:] 感觉直接使用线程池就好了，没看出来这里使用队列的意义在哪？

直接用线程池的话， 如果线程池处理不过来，怎么通知客户端，说已经满了处理不过来了？[/quote] ThreadPoolExecutor 类不是可以使用相关的 RejectedExecutionHandler 接口么？默认的是 AbortPolicy 实现，即抛出异常。[/quote] 哦，thank you，这样改了

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		String jsonData = request.getParameter("json");
		PrintWriter out = response.getWriter();

		if (jsonData != null && !jsonData.equals("")) {
			try{
				SyncQueue.exe.execute(new DealThread2(jsonData));
				out.print("ok");
			} catch (RejectedExecutionException e) {
				out.print("full");
			}

		} else {
			log.info("wrong param" + jsonData);
			out.print("wrong param");
			response.sendError(HttpServletResponse.SC_BAD_REQUEST);
		}
	}

[miracleliu]

又没人理了。。我顶

[火龙果被占用了]

感觉直接使用线程池就好了，没看出来这里使用队列的意义在哪？

[其实我是真性情]

队列JAVA里不是先现成的嘛？为什么要自己写？

[致知Fighting]

线程池同样也支持把超出的任务放进队列的操作，为什么lz要自己写一个队列先入列再起线程，感觉和直接用线程池没有区别，反而复杂了