使函数无法在Java中运行几秒钟

Question

我有一个登录功能，如果用户调用它超过5次，我希望我的功能在10秒钟内不起作用，那我该怎么办？如果有人回答我的问题，我会很高兴。

Answer 1

You need to record failed login attempts for a user (eg in database ) and once it reaches the threshold, you need to return error response from login method for configurable amount of time from the last failed login attempt, eg:

• When a login fails, log it into database (along with timestamp)
• During login attempt, get failed attempt count and check whether it has reached the configured threshold
• If it is over the threshold, check the timestamp for last login and block the call if current date is let's say within x minutes from that timestamp
• On successful login, clear all the failed attempts

Answer 2

function not work for example 10 seconds

You need to be specific on what exactly you mean by function not to work . But if you simply wanted to block the method call for x seconds, follow the below approach:

You need to create a counter to count the number of attempts and then if(counter>5) then use Thread.sleep(10000) to make the request to hold (sleep) for 10 seconds. Ideally, the counter value should be persisted to a database (or any other storage) and read it again to validate the number of attempts.

But, I strongly suggest you follow @Darshan's answer which makes more sense.

Answer 3

First you need to identify the user .

This can be done on the basis of IP .

Have a ConcurrentHashMap

   ConcurrentHashMap<String,Long>IpAddressValidationMap  // String is the Ip address and Long is the timeInMilleseconds

You make a filter and put a check

     public void prefilterFunction(RequestObject object)
      {
          String ip=object.getIP(); // just an example not the standard call for getting Ip addr
           Long time=IpAddressValidationMap.get(ip);
           if(time!=null)
           { 
             if(time<THRESHOLD_TIME)
               {
                 return ;  
                 }     
                 else
                {
                 // We allow the user to proceed
                 }
            }
       }

      public void validateLogin(RequestObject object)
      {
       // if the login fails 
         IpAddressValidationMap.put(ipAddr,System.currentTimeinMIllis());   
       }