建立网站分为几阶段,以家为主题做网站,专业制作网站报价,wordpress apache内存最近几天在测境碰到一个问题#xff0c;httpclient 在使用线程池时, 间隔性的出现 NoHttpResponseException 异常。
httpclient org.apache.http.NoHttpResponseException: host:443 failed to respond
用了连接池很多年了, 一搜自己的博客, 竟然没做过一次整… 最近几天在测境碰到一个问题httpclient 在使用线程池时, 间隔性的出现 NoHttpResponseException 异常。
httpclient org.apache.http.NoHttpResponseException: host:443 failed to respond
用了连接池很多年了, 一搜自己的博客, 竟然没做过一次整理和收藏, 其实大致原因也猜出个八九不离十, 秉承着严谨的态度, 还是百度了一下...大致总结出2个原因 1.当服务端由于负载过大等情况发生时可能会导致在收到请求后无法处理(比如没有足够的线程资源)会直接丢弃链接而不进行处理。此时客户端就会报错NoHttpResponseException。 解决建议 重试
2.客户端与服务端建立的请求在服务端已经失效。例如服务端 springboot 内置 tomcat 默认 keepAliveTimeout 20s客户端自定义 keepAliveTimeout 30s客户端连接池中取出的空闲连接可能已经被服务端失效再次从连接池拿该失效连接进行请求时就会报错。 解决建议检查并关闭失效连接
问题依然解决, 解决过程中温习的知识还是需要记载下, 方便下次出现问题, 或者自己再次使用和有需要的小伙伴方便查找,
PoolingHttpClientConnectionManager pool new PoolingHttpClientConnectionManager(socketFactoryRegistry);// pool max connectpool.setMaxTotal(maxTotal);// 设置最大路由pool.setDefaultMaxPerRoute(defaultMaxPerRoute);RequestConfig requestConfig RequestConfig.custom().setConnectionRequestTimeout(connectionRequestTimeout).setSocketTimeout(socketTimeout).setConnectTimeout(connectTimeout).build();HttpClientUtil.closeableHttpClient HttpClients.custom()// 设置连接池管理.setConnectionManager(pool)// 设置请求配置.setDefaultRequestConfig(requestConfig)//问题一解决方案设置重试.setServiceUnavailableRetryStrategy(new DefaultServiceUnavailableRetryStrategy(3, 2000))//问题二解决方案调整 keepAliveTimeout这样无法复用长连接.setKeepAliveStrategy(new DefaultConnectionKeepAliveStrategy())//问题二解决方案设置重试次数.setRetryHandler(new DefaultHttpRequestRetryHandler(3, false))//问题二解决方案设置自动关闭过期链接.evictIdleConnections(30, TimeUnit.SECONDS).build();
对于问题二解决方案中evictIdleConnections方法的工作原理感兴趣的同学, 可以查看源码, 这里贴出部分代码, 供参考, 其实自己实现也一样
初始化变量 HttpClientBuilder.evictIdleConnections()
public final HttpClientBuilder evictIdleConnections(final long maxIdleTime, final TimeUnit maxIdleTimeUnit) {this.evictIdleConnections true;this.maxIdleTime maxIdleTime;this.maxIdleTimeUnit maxIdleTimeUnit;return this;}
构建逻辑 HttpClientBuilder.build()
if (evictExpiredConnections || evictIdleConnections) {final IdleConnectionEvictor connectionEvictor new IdleConnectionEvictor(cm,maxIdleTime 0 ? maxIdleTime : 10, maxIdleTimeUnit ! null ? maxIdleTimeUnit : TimeUnit.SECONDS,maxIdleTime, maxIdleTimeUnit);closeablesCopy.add(new Closeable() {Overridepublic void close() throws IOException {connectionEvictor.shutdown();try {connectionEvictor.awaitTermination(1L, TimeUnit.SECONDS);} catch (final InterruptedException interrupted) {Thread.currentThread().interrupt();}}});connectionEvictor.start();} 初始化链接处理线程 IdleConnectionEvictor public IdleConnectionEvictor(final HttpClientConnectionManager connectionManager,final ThreadFactory threadFactory,final long sleepTime, final TimeUnit sleepTimeUnit,final long maxIdleTime, final TimeUnit maxIdleTimeUnit) {this.connectionManager Args.notNull(connectionManager, Connection manager);this.threadFactory threadFactory ! null ? threadFactory : new DefaultThreadFactory();this.sleepTimeMs sleepTimeUnit ! null ? sleepTimeUnit.toMillis(sleepTime) : sleepTime;this.maxIdleTimeMs maxIdleTimeUnit ! null ? maxIdleTimeUnit.toMillis(maxIdleTime) : maxIdleTime;this.thread this.threadFactory.newThread(new Runnable() {Overridepublic void run() {try {while (!Thread.currentThread().isInterrupted()) {Thread.sleep(sleepTimeMs);connectionManager.closeExpiredConnections();if (maxIdleTimeMs 0) {connectionManager.closeIdleConnections(maxIdleTimeMs, TimeUnit.MILLISECONDS);}}} catch (final Exception ex) {exception ex;}}});}
