1.http连接池不是万能的,过多的长连接会占用服务器资源,导致其他服务受阻
2.http连接池只适用于请求是经常访问同一主机(或同一个接口)的情况下
3.并发数不高的情况下资源利用率低下
1.复用http连接,省去了tcp的3次握手和4次挥手的时间,极大降低请求响应的时间
2.自动管理tcp连接,不用人为地释放/创建连接
1.创建PoolingHttpClientConnectionManager实例
2.给manager设置参数
3.给manager设置重试策略
4.给manager设置连接管理策略
5.开启监控线程,及时关闭被服务器单向断开的连接
6.构建HttpClient实例
7.创建HttpPost/HttpGet实例,并设置参数
8.获取响应,做适当的处理
9.将用完的连接放回连接池
public class HttpConnectionPoolUtil { private static Logger logger = LoggerFactory.getLogger(HttpConnectionPoolUtil.class); private static final int CONNECT_TIMEOUT = Config.getHttpConnectTimeout();// 设置连接建立的超时时间为10s private static final int SOCKET_TIMEOUT = Config.getHttpSocketTimeout(); private static final int MAX_CONN = Config.getHttpMaxPoolSize(); // 最大连接数 private static final int Max_PRE_ROUTE = Config.getHttpMaxPoolSize(); private static final int MAX_ROUTE = Config.getHttpMaxPoolSize(); private static CloseableHttpClient httpClient; // 发送请求的客户端单例 private static PoolingHttpClientConnectionManager manager; //连接池管理类 private static ScheduledExecutorService monitorExecutor; private final static Object syncLock = new Object(); // 相当于线程锁,用于线程安全 /** * 对http请求进行基本设置 * @param httpRequestBase http请求 */ private static void setRequestConfig(HttpRequestBase httpRequestBase){ RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(CONNECT_TIMEOUT) .setConnectTimeout(CONNECT_TIMEOUT) .setSocketTimeout(SOCKET_TIMEOUT).build(); httpRequestBase.setConfig(requestConfig); } public static CloseableHttpClient getHttpClient(String url){ String hostName = url.split("/")[2]; System.out.println(hostName); int port = 80; if (hostName.contains(":")){ String[] args = hostName.split(":"); hostName = args[0]; port = Integer.parseInt(args[1]); } if (httpClient == null){ //多线程下多个线程同时调用getHttpClient容易导致重复创建httpClient对象的问题,所以加上了同步锁 synchronized (syncLock){ if (httpClient == null){ httpClient = createHttpClient(hostName, port); //开启监控线程,对异常和空闲线程进行关闭 monitorExecutor = Executors.newScheduledThreadPool(1); monitorExecutor.scheduleAtFixedRate(new TimerTask() { @Override public void run() { //关闭异常连接 manager.closeExpiredConnections(); //关闭5s空闲的连接 manager.closeIdleConnections(Config.getHttpIdelTimeout(), TimeUnit.MILLISECONDS); logger.info("close expired and idle for over 5s connection"); } }, Config.getHttpMonitorInterval(), Config.getHttpMonitorInterval(), TimeUnit.MILLISECONDS); } } } return httpClient; } /** * 根据host和port构建httpclient实例 * @param host 要访问的域名 * @param port 要访问的端口 * @return */ public static CloseableHttpClient createHttpClient(String host, int port){ ConnectionSocketFactory plainSocketFactory = PlainConnectionSocketFactory.getSocketFactory(); LayeredConnectionSocketFactory sslSocketFactory = SSLConnectionSocketFactory.getSocketFactory(); Registry<ConnectionSocketFactory> registry = RegistryBuilder.<ConnectionSocketFactory> create().register("http", plainSocketFactory) .register("https", sslSocketFactory).build(); manager = new PoolingHttpClientConnectionManager(registry); //设置连接参数 manager.setMaxTotal(MAX_CONN); // 最大连接数 manager.setDefaultMaxPerRoute(Max_PRE_ROUTE); // 路由最大连接数 HttpHost httpHost = new HttpHost(host, port); manager.setMaxPerRoute(new HttpRoute(httpHost), MAX_ROUTE); //请求失败时,进行请求重试 HttpRequestRetryHandler handler = new HttpRequestRetryHandler() { @Override public boolean retryRequest(IOException e, int i, HttpContext httpContext) { if (i > 3){ //重试超过3次,放弃请求 logger.error("retry has more than 3 time, give up request"); return false; } if (e instanceof NoHttpResponseException){ //服务器没有响应,可能是服务器断开了连接,应该重试 logger.error("receive no response from server, retry"); return true; } if (e instanceof SSLHandshakeException){ // SSL握手异常 logger.error("SSL hand shake exception"); return false; } if (e instanceof InterruptedIOException){ //超时 logger.error("InterruptedIOException"); return false; } if (e instanceof UnknownHostException){ // 服务器不可达 logger.error("server host unknown"); return false; } if (e instanceof ConnectTimeoutException){ // 连接超时 logger.error("Connection Time out"); return false; } if (e instanceof SSLException){ logger.error("SSLException"); return false; } HttpClientContext context = HttpClientContext.adapt(httpContext); HttpRequest request = context.getRequest(); if (!(request instanceof HttpEntityEnclosingRequest)){ //如果请求不是关闭连接的请求 return true; } return false; } }; CloseableHttpClient client = HttpClients.custom().setConnectionManager(manager).setRetryHandler(handler).build(); return client; } /** * 设置post请求的参数 * @param httpPost * @param params */ private static void setPostParams(HttpPost httpPost, Map<String, String> params){ List<NameValuePair> nvps = new ArrayList<NameValuePair>(); Set<String> keys = params.keySet(); for (String key: keys){ nvps.add(new BasicNameValuePair(key, params.get(key))); } try { httpPost.setEntity(new UrlEncodedFormEntity(nvps, "utf-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } public static JsonObject post(String url, Map<String, String> params){ HttpPost httpPost = new HttpPost(url); setRequestConfig(httpPost); setPostParams(httpPost, params); CloseableHttpResponse response = null; InputStream in = null; JsonObject object = null; try { response = getHttpClient(url).execute(httpPost, HttpClientContext.create()); HttpEntity entity = response.getEntity(); if (entity != null) { in = entity.getContent(); String result = IOUtils.toString(in, "utf-8"); Gson gson = new Gson(); object = gson.fromJson(result, JsonObject.class); } } catch (IOException e) { e.printStackTrace(); } finally { try{ if (in != null) in.close(); if (response != null) response.close(); } catch (IOException e) { e.printStackTrace(); } } return object; } /** * 关闭连接池 */ public static void closeConnectionPool(){ try { httpClient.close(); manager.close(); monitorExecutor.shutdown(); } catch (IOException e) { e.printStackTrace(); } }}
作者:PigPIgAutumn
链接:https://www.jianshu.com/p/c852cbcf3d68
来源:简书
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