blankmiss
V2EX  ›  问与答

请教一下,为什么我的代码运行 1-2 分钟后会突然核心满载(服务器)然后程序就卡住了

  •  1
     
  •   blankmiss · Apr 16, 2024 · 1609 views
    This topic created in 774 days ago, the information mentioned may be changed or developed.

    运行环境

    oracle 圣何塞 debian arm 4C 24G

    JDK 21, 不能在本地上复现 代理程序在 服务器上

    htop 观察到 是某一个核心突然满载 然后就卡住了

    代码

    public class Main {
    
        static Log log = Log.get();
        static final Gson gson = new Gson();
        static List<Image> images = null;
        static int maxThreads = 100; // 控制固定线程池的大小
        static ExecutorService virtualThreadPool = Executors.newFixedThreadPool(maxThreads, Thread.ofVirtual().factory());
        static String filePath = "/root/java_work/imglist/";
        // 失败 list
        static List<String> failList = Lists.newArrayList();
    
        public static void main(String[] args) {
            OkHttpUtils.setProxy(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("127.0.0.1", 6789)));
            List<String> types = List.of(".jpg", ".png");
            try {
                images = gson.fromJson(new FileReader("output-2024-4-16.json"), new TypeToken<List<Image>>(){}.getType());
            } catch (IOException e) {
                log.info("读取文件失败: {}", e.getMessage());
                return;
            }
    
            log.info("加载到的图片数量: {}", images.size());
    
            images.forEach(image -> virtualThreadPool.submit(() -> {
                for (String type : types) {
                    String url = convertPreviewToImageUrl(image.getHref(), type);
                    if (attemptToDownloadImage(url,0)) {
                        image.setSourceUrl(url);  // 更新 Image 对象
                        break;
                    }
                }
            }));
            virtualThreadPool.shutdown();
            while (!virtualThreadPool.isTerminated()) {
                Thread.onSpinWait();
            }
            // 将更新后的 images 列表写回到 JSON 文件
            writeImagesToJson(images, "output-2024-4-16-ok.json");
            writeImagesToJson(failList, "output-2024-4-16-fail.json");
        }
    
        private static boolean attemptToDownloadImage(String url, int retryCount) {
            if (retryCount >= 3) {
                log.info("重试次数过多,放弃下载: {}", url);
                failList.add(url);
                return false;
            }
            try (Response response = OkHttpUtils.get(url, Headers.of("Connection", "close"))) {
                switch (response.code()) {
                    case 200:
                        log.info("成功下载图片: {}", url);
                        byte[] bytes = Objects.requireNonNull(response.body()).bytes();
                        writeImageToFile(bytes, url.substring(url.lastIndexOf('/') + 1));
                        return true;
                    case 404:
                        log.info("图片不存在: {}", url);
                        return false;
                    case 429:
                        log.info("请求过于频繁,需要稍后重试: {}", url);
                        handleRateLimiting();
                        return attemptToDownloadImage(url, retryCount + 1);
                    default:
                        log.info("其他 HTTP 响应: {}", response.code());
                        return false;
                }
            } catch (Exception e) {
                log.error("请求图片时出错: {}", e.fillInStackTrace());
                handleRateLimiting();
                return attemptToDownloadImage(url, retryCount + 1);
            }
        }
    
        private static void handleRateLimiting() {
            try {
                log.info("等待 5 秒后重试");
                Thread.sleep(5000); // 延迟 5 秒后重试
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    
        public static String convertPreviewToImageUrl(String previewUrl, String type) {
            String id = previewUrl.substring(previewUrl.lastIndexOf('/') + 1);
            return String.format("https://w.wallhaven.cc/full/%s/wallhaven-%s%s", id.substring(0, 2), id, type);
        }
    
        public static void writeImagesToJson(List<?> objects,String fileName) {
            try (FileWriter writer = new FileWriter(fileName)) {
                gson.toJson(objects, writer);
            } catch (IOException e) {
                log.error("写入文件时出错: {}", e.getMessage());
            }
        }
    
        public static void writeImageToFile(byte[] bytes, String fileName) {
            try (FileOutputStream fos = new FileOutputStream(filePath+fileName)) {
                fos.write(bytes);
                log.info("成功写入文件: {}", fileName);
            } catch (IOException e) {
                log.error("写入文件时出错: {}", e.getMessage());
            }
        }
    }
    

    https://gist.github.com/dnslin/fe657f9df08f4286c197c5e9e5fd6a51

    6 replies    2024-04-16 23:24:01 +08:00
    blankmiss
        1
    blankmiss  
    OP
       Apr 16, 2024
    我尝试削减过 线程池的数量 减到了 6 个 都会卡住
    blankmiss
        2
    blankmiss  
    OP
       Apr 16, 2024
    但是我改成线程池就不会出现这种情况
    sagaxu
        3
    sagaxu  
       Apr 16, 2024   ❤️ 1
    1. 很多第三方库甚至 JDK 库尚不支持虚拟线程
    2. 用 JFR 记录观察是哪个地方卡住了
    3. onSpinWait 换成 Thread.sleep 试试,busy-waiting 不宜等待太久
    blankmiss
        4
    blankmiss  
    OP
       Apr 16, 2024
    @sagaxu 意思是在某些情况下 虚拟线程会被阻塞掉? 第三点我去试试 我现在已经在用 arthas-boot.jar 分析了
    zizon
        5
    zizon  
       Apr 16, 2024
    failList 换线程安全的看看?
    blankmiss
        6
    blankmiss  
    OP
       Apr 16, 2024
    @zizon 和这个没关系 我感觉是虚拟线程占满了 IO (可能)但是线程池就没问题
    About   ·   Help   ·   Advertise   ·   Blog   ·   API   ·   FAQ   ·   Solana   ·   2785 Online   Highest 6679   ·     Select Language
    创意工作者们的社区
    World is powered by solitude
    VERSION: 3.9.8.5 · 38ms · UTC 09:30 · PVG 17:30 · LAX 02:30 · JFK 05:30
    ♥ Do have faith in what you're doing.