SSL握手时，服务端发送的ChangeCipherSpec和Finished为何会间隔很久？

Question

用SSLServerSocketFactory实现了一个简单的HTTPS服务器，代码如下： public static void main(String[] args) throws Exception { KeyStore ks = KeyStore.getInstance("PKCS12"); ks.load(TestEcho.class.getResourceAsStream("/localhost.pfx"), "****".toCharArray()); KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509"); kmf.init(ks, "****".toCharArray()); SSLContext sslc = SSLContext.getInstance("TLS"); sslc.init(kmf.getKeyManagers(), null, null); // try (ServerSocket server = new ServerSocket(4443)) { try (ServerSocket server = sslc.getServerSocketFactory().createServerSocket(4443)) { while (true) { Socket socket = server.accept(); // ((SSLSocket) socket).getSession(); socket.getInputStream().read(); socket.getOutputStream().write("HTTP/1.1 200 OK\r\nContent-Length: 2\r\nConnection: close\r\n\r\nok".getBytes()); socket.getOutputStream().flush(); } } } 后来压测时发现性能比Tomcat的HTTPS慢好多(Tomcat采用BIO模式)，抓包时发现这么个问题：服务端发送的ChangeCipherSpec和Finished之间有长达100多ms的间隔。TCP包内容是： [127.0.0.1:1962 Connected at 00:58:21.718] [127.0.0.1:1962 Sent at 00:58:21.718] // ClientHello 0000:0000 16 03 03 00 C3 01 00 00-BF 03 03 59 82 04 AD 44 ...........Y...D ... 0000:00C0 02 03 02 01 02 02 01 01 ........ [127.0.0.1:1962 Received at 00:58:21.781] // ServerHello & Certificate & ServerHelloDone 0000:0000 16 03 03 0B EB 02 00 00-4D 03 03 59 82 04 A8 14 ........M..Y.... ... 0000:0BE0 12 0D 53 CB B6 20 64 BC-8E 77 3A 0F 0E 00 00 00 ..S.. d..w:..... [127.0.0.1:1962 Sent at 00:58:21.812] // ClientKeyExchange 0000:0000 16 03 03 00 46 10 00 00-42 41 04 ED DD 67 FB 22 ....F...BA...g." ... 0000:0040 39 50 1F 50 F2 12 62 A7-3D C8 FE 9P.P..b.=.. [127.0.0.1:1962 Sent at 00:58:21.828] // Client ChangeCipherSpec 0000:0000 14 03 03 00 01 01 ...... [127.0.0.1:1962 Sent at 00:58:21.828] // Client Finished 0000:0000 16 03 03 00 50 8E DB DC-39 07 9B 68 36 17 BB 44 ....P...9..h6..D ... 0000:0050 B3 5E 91 FF E8 .^... [127.0.0.1:1962 Received at 00:58:21.890] // Server ChangeCipherSuite 0000:0000 14 03 03 00 01 01 ...... [127.0.0.1:1962 Received at 00:58:22.046] // Server Finished, but delayed 156ms !!! 0000:0000 16 03 03 00 50 71 68 70-ED 8F D6 73 11 94 DD F4 ....Pqhp...s.... 0000:0010 D9 A4 1F 60 BA 48 43 B0-4B 53 EF 66 E5 59 F2 8B ...`.HC.KS.f.Y.. 0000:0020 DD CE D7 D5 8F C4 68 A2-87 07 92 A9 3B D9 9B 3B ......h.....;..; 0000:0030 DD DE 1A 71 6F 87 8D 59-17 6F 8F 94 2C 89 01 DA ...qo..Y.o..,... 0000:0040 E9 7D 08 E2 F2 FC 54 BF-FA 8D 45 F8 7B B0 29 8D .}....T...E.{.). 0000:0050 CE 87 CF 81 E1 ..... [127.0.0.1:1962 Sent at 00:58:22.046] // HTTP Request 0000:0000 17 03 03 00 A0 73 85 EE-93 BC 66 94 76 6D 49 74 .....s....f.vmIt ... 0000:00A0 DE C2 BE DD 46 ....F [127.0.0.1:1962 Received at 00:58:22.062] // HTTP Response 0000:0000 17 03 03 02 70 E8 CF 13-B4 E0 4F 32 8E 6F 37 74 ....p.....O2.o7t ... 0000:0270 DD 5B FB 99 9D .[... [127.0.0.1:1962 Sent at 00:58:22.062] // Disconnect 0000:0000 15 03 03 00 40 42 BC E5-B7 B2 E4 B5 22 D2 DF 75 ....@B......"..u ... 0000:0040 B8 59 B2 89 FB .Y... [127.0.0.1:1962 Disconnected at 00:58:22.062] 而在测Tomcat时，没有这样的间隔，抓包是： ... [127.0.0.1:1968 Received at 00:58:50.312] // server-side ChangeCipherSpec & Finished 0000:0000 14 03 03 00 01 01 16 03-03 00 50 03 0D D0 FE 94 ..........P..... 0000:0010 5D 0B 22 60 62 46 F3 29-D9 37 B7 D1 42 60 5A 6A ]."`bF.).7..B`Zj 0000:0020 93 C8 1F CF D8 B9 81 7D-DD 3D A9 1E A0 F0 C0 05 .......}.=...... 0000:0030 11 C8 C4 B9 31 16 E5 1E-2F 43 EA 45 2A F0 E8 BF ....1.../C.E*... 0000:0040 9E BD 20 84 8E 5A 1A 57-0B 31 32 BE 5E 6C B3 F3 .. ..Z.W.12.^l.. 0000:0050 6A 00 95 D3 75 32 03 35-83 3D 12 j...u2.5.=. ... 是不是我的程序里SSLContext、KeyManagers或SSL握手写法不对？