应用程序抛出错误，然后无法连接到API。必须重新启动应用程序和Web服务器才能使应用程序再次运行，这真的令人沮丧。
cm = new PoolingHttpClientConnectionManager();
cm.setMaxTotal(100);
cm.setDefaultMaxPerRoute(50);
httpClient = HttpClients.custom().setConnectionManager(cm).build();
使用CloseableHttpClient和CloseableHttpResponse处理请求和响应。
CloseableHttpResponse在最后一节中关闭。
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1294: Shutdown connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.execchain.MainClientExec- Connection discarded
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager- Connection released: [id: 1294][route: {s}->https://xxx.xx.com:443][total kept alive: 10; route allocated: 11 of 50; total allocated: 11 of 100]
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager- Connection manager is shutting down
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1303: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1301: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1300: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1281: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1258: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1296: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1302: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1278: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1291: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-1298: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.DefaultManagedHttpClientConnection- http-outgoing-596: Close connection
["http-bio-8080"-exec-1832] DEBUG org.apache.http.impl.conn.PoolingHttpClientConnectionManager- Connection manager shut down
["http-bio-8080"-exec-296] DEBUG org.apache.http.wire- http-outgoing-596 << "[read] I/O error: Socket closed"
["http-bio-8080"-exec-1832] ERROR com.xx.xxxxxxx.xxx.util.HttpClientHelper- Error while invoking web service
java.net.SocketTimeoutException: Read timed out