Nrthugu

This makes me really curious.There is a button which sends a simple post request by ajax on a jsp page,and I use a RESTFUL method to handle this request,but that method will be executed twice or three times.This will only happen on CentOS 7.3,on my laptop I use windows10, multi-thread will not happen.I have searched on Google but nothing helpful
has been found.Here are the codes:

asset.jsp:

<button class="btn btn-default btn-sm" title="allDoMi">

      <i class="fa fa-arrow-down">allDoMi</i>

</button>

$("button[title='allDoMi']").click(function () {

    var dataparam = "version=1";

    if (!confirm('confirm all DoMi？'))

        return;

    //ajax request

    $.ajax({

        contentType: "application/json",

        url: serviceurl.baseurl + "/asset/doMiAction",

        data: dataparam,

        beforeSend: function () {

             //do nothing

        },

        error: function () {

             //do nothing

        },

        success: function (info) {

             //do nothing    

        }

    });

});

Asset.java

@Service

@Path("/asset")

public class AssetRest {

    @Path("/doMiAction")

    @POST

    @Produces({ MediaType.APPLICATION_JSON, 

                                 MediaType.APPLICATION_XML })

    public RestfulResult doMiAction(@FormParam("version") String 

          version) {

          logger.info("doMiAction method began....");

          //package data for duMiSyncDtos,here only for test

          List<DuMiSyncDto> duMiSyncDtos =new List<>();

          //this url is for http simulation using HttpURLConnection

          final String dumiUrl = "http://someip/someurl";

          final Map<String, List<DuMiSyncDto>> map; 

          //only continue when list is not empty

          if (!duMiSyncDtos.isEmpty()) {

             //this method used for sync data in a certain order

             map = groupList(duMiSyncDtos);

             SortedSet<String> ss = new TreeSet<>(map.keySet());

             final Iterator<String> iter = ss.iterator();

             final ScheduledExecutorService ticker = Executors.newSingleThreadScheduledExecutor();

             logger.info("NEW A SINGLETHREADSCHEDULEDEXECUTOR");

             //retrieve data from a .property file,I set it 20000,therefore the job will be executed in every 20 seconds

             final int DELAY = NumberUtils.toInt(WebUtils.getConfigValue("dumi.delay"));

             ticker.scheduleWithFixedDelay(new Runnable() {

             private int count;

             public void run() {

                logger.info("BEGIN RUN METHOD:"+System.identityHashCode(AssetRest.this));

                if(iter.hasNext()) {

                    try {

                        List<DuMiSyncDto> value = map.get(iter.next());

                        //this method used for simulating a httprequest using HttpURLConnection to invoke a remote service to get the result info which forms in a JSON string format

                        String resultmsg = getDuMiReturnMessage(dumiUrl,value);

                        if(resultmsg!=null && !resultmsg.contains(""code":"0000"")) {

                            logger.info("Return code is "+resultmsg+",the sync work will be terminated.");

                            ticker.shutdown();

                            return;

                        }

                        //this method used for showing some useful infomation on the console using log4j

                        showSyncInfomation(value);

                        //this method used for count how many items have been synchronized successfully

                        int currentcount = getSyncCount(resultmsg);

                        count += currentcount ;

                        logger.info("current sync  data:"+currentcount+"，summing data"+count+"");

                    } catch (Exception e) {

                        logger.error("method[doMiAction]...executing schedule:",e);

                    }

                } else {

                    ticker.shutdown();

                }

            }

        }, 0, DELAY, TimeUnit.MILLISECONDS);

    }

}

After I click the button,all the log info will be shown on Putty console for two or three times,yet I have clicked that button for only ONCE!I have tested for several times,it will happen,but in windows on my laptop,this will not happen at all.Here is a detail might be help:previously the implementation for timed execution is not like this,it has been written like :

for(DuMiSyncDto dto:duMiSyncDtoList){

    //do the business code

    Thread.sleep(20000);

}

Because there is database synchronization from the remote service,I need to control the interval time not too soon between every two operations:execute in every 20 seconds and 100 data at a time.In this situation,the multi-thread problem occurs,I thought it may be the for loop which aroused so I change the way using a JDK API instead but issues were still there.So WHY all of these?

---------------------------first edit------------------------------------------

private int getSyncCount(String resultmsg) {

    int count = 0;

    JSONObject obj = JSONObject.fromObject(resultmsg);

    String message = obj.getString("message");

    if(!WebUtils.isEmpty(message)) {

        String arr = message.split(" ");

        if(arr!=null && arr.length>1) {

            count += Integer.parseInt(arr[1].trim());

        }

    }

    logger.info("currentThreadName:"+Thread.currentThread().getName());

    return count;

}

Notice in this method,I log the current thread name,and it shows :

...     

currentThreadName:pool-1-thread-1

currentThreadName:pool-2-thread-1

currentThreadName:pool-3-thread-1

...

when there are 3 threads.