spring boot 每隔一段時(shí)間后第一次請求耗時(shí)特別長（內(nèi)含詳情）

2017-08-25 更新
發(fā)現(xiàn)，在訪問任何一個(gè)接口后，接著的接口在短時(shí)間內(nèi)訪問速度都很正常。
且該情況，無論是否通過nginx 代理都是這樣。
始終是隔一段時(shí)間后的第一個(gè)接口訪問速度很慢。

背景
1、 應(yīng)用基于 Spring Boot
2、 調(diào)試部分已獨(dú)立出來為單一的 Get 請求接口。
3、 該接口僅僅返回一個(gè)普通json，包含服務(wù)器時(shí)間、應(yīng)用名稱、請求狀態(tài)等信息，無任何I/O、數(shù)據(jù)庫等復(fù)雜操作。
4、 項(xiàng)目啟動方式為 打包后通過 java -jar xxx.war 啟動，上層由 nginx 托管。
5、 Spring Boot 啟動端口為8000, nginx 端口為9999

問題
無論用瀏覽器、Postman、curl、Python(requests) 去訪問接口，均得到第一次響應(yīng)非常耗時(shí)，短時(shí)間內(nèi)第二次訪問會快很多。

分析
1、暫時(shí)通過日志判斷出控制臺輸出請求頭部分的前后耗時(shí)非常長，但是不明白下一步該去怎么分析找問題。
2、單獨(dú)接口部分的請求響應(yīng)很快。

請各位幫忙分析下，以下為代碼。

接口代碼

    @RequestMapping(value = "/status")
    @ResponseBody
    public
    Map<String, Object> status(HttpServletRequest request){
        Map<String, Object> m = new HashMap<>;

        m.put("name", "*****");
        m.put("remote_addr", request.getHeader("X-Real-Addr"));

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Calendar calendar = Calendar.getInstance();
        m.put("time", sdf.format(calendar.getTime()));


        return m;
    }

日志設(shè)置代碼

#logging(TRACE DEBUG INFO WARN)
logging.level.org.apache=debug
logging.level.org.springframework=INFO
logging.level.org.springframework.jdbc.core.StatementCreatorUtils=TRACE
logging.level.org.springframework.jdbc.core=DEBUG

日志代碼

2017-08-22 16:28:54,430 [http-nio-8000-Acceptor-0] DEBUG o.a.tomcat.util.threads.LimitLatch - Counting up[http-nio-8000-Acceptor-0] latch=1
2017-08-22 16:28:54,430 [http-nio-8000-exec-2] DEBUG o.a.coyote.http11.Http11NioProtocol - Processing socket [org.apache.tomcat.util.net.NioChannel@16655a47:java.nio.channels.SocketChannel[connected local=/192.168.0.30:8000 remote=/192.168.0.30:55507]] with status [OPEN_READ]
2017-08-22 16:28:54,431 [http-nio-8000-exec-2] DEBUG o.a.coyote.http11.Http11InputBuffer - Received [GET /rest/db/status HTTP/1.0
X-Real-Addr: 192.168.1.106
X-Real-Port: 54620
HostAddr: http://192.168.1.30
HostPort: 9999
project: /rest
ServerAddr: http://192.168.1.30:9999
Host: 192.168.0.30:8000
Connection: close
Pragma: no-cache
Cache-Control: no-cache
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.101 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.8

]
2017-08-22 16:28:55,843 [http-nio-8000-exec-2] DEBUG o.a.c.a.AuthenticatorBase - Security checking request GET /rest/db/status
2017-08-22 16:28:55,843 [http-nio-8000-exec-2] DEBUG org.apache.catalina.realm.RealmBase -   No applicable constraints defined
2017-08-22 16:28:55,843 [http-nio-8000-exec-2] DEBUG o.a.c.a.AuthenticatorBase -  Not subject to any constraint
2017-08-22 16:28:55,843 [http-nio-8000-exec-2] DEBUG o.apache.tomcat.util.http.Parameters - Set encoding to UTF-8
2017-08-22 16:28:55,844 [http-nio-8000-exec-2] INFO  org.kys.log.spring.LogInterceptor - start [/rest/db/status]
2017-08-22 16:28:55,847 [http-nio-8000-exec-2] INFO  org.kys.log.spring.LogInterceptor - complete [/rest/db/status] :: Time Taken=3
2017-08-22 16:28:55,847 [http-nio-8000-exec-2] DEBUG o.a.coyote.http11.Http11Processor - Socket: [org.apache.tomcat.util.net.NioEndpoint$NioSocketWrapper@75160339:org.apache.tomcat.util.net.NioChannel@16655a47:java.nio.channels.SocketChannel[connected local=/192.168.0.30:8000 remote=/192.168.0.30:55507]], Status in: [OPEN_READ], State out: [CLOSED]
2017-08-22 16:28:55,848 [http-nio-8000-exec-2] DEBUG o.a.tomcat.util.threads.LimitLatch - Counting down[http-nio-8000-exec-2] latch=1
2017-08-22 16:29:03,493 [http-nio-8000-Acceptor-0] DEBUG o.a.tomcat.util.threads.LimitLatch - Counting up[http-nio-8000-Acceptor-0] latch=1
2017-08-22 16:29:03,503 [http-nio-8000-exec-3] DEBUG o.a.coyote.http11.Http11NioProtocol - Processing socket [org.apache.tomcat.util.net.NioChannel@16655a47:java.nio.channels.SocketChannel[connected local=/192.168.0.30:8000 remote=/192.168.0.30:55520]] with status [OPEN_READ]
2017-08-22 16:29:03,504 [http-nio-8000-exec-3] DEBUG o.a.coyote.http11.Http11InputBuffer - Received [GET /rest/db/status HTTP/1.0
X-Real-Addr: 192.168.1.106
X-Real-Port: 54620
HostAddr: http://192.168.1.30
HostPort: 9999
project: /rest
ServerAddr: http://192.168.1.30:9999
Host: 192.168.0.30:8000
Connection: close
Pragma: no-cache
Cache-Control: no-cache
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/60.0.3112.101 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.8

]
2017-08-22 16:29:03,507 [http-nio-8000-exec-3] DEBUG o.a.c.a.AuthenticatorBase - Security checking request GET /rest/db/status
2017-08-22 16:29:03,508 [http-nio-8000-exec-3] DEBUG org.apache.catalina.realm.RealmBase -   No applicable constraints defined
2017-08-22 16:29:03,508 [http-nio-8000-exec-3] DEBUG o.a.c.a.AuthenticatorBase -  Not subject to any constraint
2017-08-22 16:29:03,508 [http-nio-8000-exec-3] DEBUG o.apache.tomcat.util.http.Parameters - Set encoding to UTF-8