CloseableHttpClient httpclient = HttpClients.createDefault();
HttpGet httpget = new HttpGet("http://localhost/");
CloseableHttpResponse response = httpclient.execute(httpget);
try {HttpEntity entity = response.getEntity();if (entity != null) {long len = entity.getContentLength();if (len != -1 && len < 2048) {System.out.println(EntityUtils.toString(entity));} else {// Stream content out}}
} finally {response.close();
}

private E getPoolEntryBlocking(final T route, final Object state,final long timeout, final TimeUnit tunit,final PoolEntryFuture<E> future)throws IOException, InterruptedException, TimeoutException {Date deadline = null;if (timeout > 0) {deadline = new Date(System.currentTimeMillis() + tunit.toMillis(timeout));}this.lock.lock();try {final RouteSpecificPool<T, C, E> pool = getPool(route);//這是每一個路由細分出來的連接池E entry = null;while (entry == null) {Asserts.check(!this.isShutDown, "Connection pool shut down");//從池子中獲取一個可用連接并返回for (;;) {entry = pool.getFree(state);if (entry == null) {break;}if (entry.isExpired(System.currentTimeMillis())) {entry.close();} else if (this.validateAfterInactivity > 0) {if (entry.getUpdated() + this.validateAfterInactivity <= System.currentTimeMillis()) {if (!validate(entry)) {entry.close();}}}if (entry.isClosed()) {this.available.remove(entry);pool.free(entry, false);} else {break;}}if (entry != null) {this.available.remove(entry);this.leased.add(entry);onReuse(entry);return entry;}//創建新的連接// New connection is neededfinal int maxPerRoute = getMax(route);//獲取當前路由最大并發數// Shrink the pool prior to allocating a new connectionfinal int excess = Math.max(0, pool.getAllocatedCount() + 1 - maxPerRoute);if (excess > 0) {//如果當前路由對應的連接池的連接超過最大路由并發數，獲取到最后使用的一次連接，釋放掉for (int i = 0; i < excess; i++) {final E lastUsed = pool.getLastUsed();if (lastUsed == null) {break;}lastUsed.close();this.available.remove(lastUsed);pool.remove(lastUsed);}}//嘗試創建新的連接 if (pool.getAllocatedCount() < maxPerRoute) {//當前路由對應的連接池可用空閑連接數+當前路由對應的連接池已用連接數 < 當前路由對應的連接池最大并發數final int totalUsed = this.leased.size();final int freeCapacity = Math.max(this.maxTotal - totalUsed, 0);if (freeCapacity > 0) {final int totalAvailable = this.available.size();if (totalAvailable > freeCapacity - 1) {//線程池中可用空閑連接數 > (線程池中最大連接數 - 線程池中已用連接數 - 1)if (!this.available.isEmpty()) {final E lastUsed = this.available.removeLast();lastUsed.close();final RouteSpecificPool<T, C, E> otherpool = getPool(lastUsed.getRoute());otherpool.remove(lastUsed);}}final C conn = this.connFactory.create(route);entry = pool.add(conn);this.leased.add(entry);return entry;}}boolean success = false;try {pool.queue(future);this.pending.add(future);success = future.await(deadline);} finally {// In case of 'success', we were woken up by the// connection pool and should now have a connection// waiting for us, or else we're shutting down.// Just continue in the loop, both cases are checked.pool.unqueue(future);this.pending.remove(future);}// check for spurious wakeup vs. timeoutif (!success && (deadline != null) &&(deadline.getTime() <= System.currentTimeMillis())) {break;}}throw new TimeoutException("Timeout waiting for connection");} finally {this.lock.unlock();}
}

@Bean
public ClientHttpRequestFactory clientHttpRequestFactory()throws KeyStoreException, NoSuchAlgorithmException, KeyManagementException {HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();SSLContext sslContext = new SSLContextBuilder().loadTrustMaterial(null, (arg0, arg1) -> true).build();httpClientBuilder.setSSLContext(sslContext).setMaxConnTotal(MAX_CONNECTION_TOTAL).setMaxConnPerRoute(ROUTE_MAX_COUNT).evictIdleConnections(CONNECTION_IDLE_TIME_OUT, TimeUnit.MILLISECONDS);httpClientBuilder.setRetryHandler(new DefaultHttpRequestRetryHandler(RETRY_COUNT, true));httpClientBuilder.setKeepAliveStrategy(new DefaultConnectionKeepAliveStrategy());CloseableHttpClient client = httpClientBuilder.build();HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(client);clientHttpRequestFactory.setConnectTimeout(CONNECTION_TIME_OUT);clientHttpRequestFactory.setReadTimeout(READ_TIME_OUT);clientHttpRequestFactory.setConnectionRequestTimeout(CONNECTION_REQUEST_TIME_OUT);clientHttpRequestFactory.setBufferRequestBody(false);return clientHttpRequestFactory;
}

@Bean
public RestTemplate restTemplate()  {RestTemplate restTemplate = new RestTemplate(clientHttpRequestFactory());restTemplate.setErrorHandler(new DefaultResponseErrorHandler());// 修改StringHttpMessageConverter內容轉換器restTemplate.getMessageConverters().set(1, new StringHttpMessageConverter(StandardCharsets.UTF_8));return restTemplate;
}

@SpringBootApplication
public class Application {private static final Logger log = LoggerFactory.getLogger(Application.class);public static void main(String args[]) {SpringApplication.run(Application.class);}@Beanpublic RestTemplate restTemplate(RestTemplateBuilder builder) {return builder.build();}@Beanpublic CommandLineRunner run(RestTemplate restTemplate) throws Exception {return args -> {Quote quote = restTemplate.getForObject("https://gturnquist-quoters.cfapps.io/api/random", Quote.class);log.info(quote.toString());};}
}