Redis Implements distributed locks

2. Normal way

2. Look directly at the code

1. package com.whereta.jedis;import org.springframework.stereotype.component;import  redis.clients.jedis.jedis;import redis.clients.jedis.jedispool;import javax.annotation.resource; import java.util.calendar;import java.util.date;import java.util.concurrent.timeunit;/** *  created by vincent on 15-10-14. */@Component ("Jedislock") public class  JedisLock {    public class CacheName {         public static final string add_bean_after_check_lock_key =   "Addbeanafterchecklock";    }     @Resource      private jedispool jedispool;    public void addbeanaftercheck ( Int userid)  {        Jedis jedis =  Jedispool.getresource ();          calendar calendar = calendar.getinstance ();         calendar.set (calendar.millisecond, 0);         Date calendartime = calendar.gettime ();         long  time = calendartime.gettime ();         //with a user ID of key, Different users call the same method without locking         string key = cachename.add_bean_ after_check_lock_key +  ":"  + userid;        try  {            if  (jedis !=  NULL)  {                 Long lock = jedis.setnx (key, time +  "");                 while  (lock == 0)  {                     timeunit.milliseconds.sleep (50);                      lock = jedis.setnx (key, time +  "");                 }                 //Set timeout time                  jedis.expire (key, 3);             }            // Own business logic processing         } catch  (exception e)  {      &nbSp;      throw new runtimeexception (e);         } finally {             if  (jedis != null)  {                 jedis.del (Key);                 jedis.close ();             }        }    }}

4. In the example, the user ID is key locking: When different users access the method, they do not reject the wait

6. The implementation of the lock mechanism takes advantage of the Redis Setnx method: If a key exists in the database, it does not store the data and returns 0

8. Redis's approach is thread-safe and can be used with confidence

4. AOP approach

2. Sample code

1. package com.whereta.jedis;import org.aspectj.lang.proceedingjoinpoint;import  org.aspectj.lang.annotation.around;import org.aspectj.lang.annotation.aspect;import  org.springframework.stereotype.component;import redis.clients.jedis.jedis;import  Redis.clients.jedis.jedispool;import javax.annotation.resource;import java.util.calendar;import  java.util.date;import java.util.concurrent.timeunit;/** * created by vincent  on 15-10-14. */@Aspect @componentpublic class jedislockaop {      @Resource     private JedisPool jedisPool;     @Around (" Execution (Public * com.heli.core.pay.soaservice.impl.*.* (..)) ")     PUBLIC OBJECT SERVICEAOP (Proceedingjoinpoint point)  {         object proceed = null;      & NBsp; jedis jedis = jedispool.getresource ();         calendar calendar = calendar.getinstance ();         calendar.set (calendar.millisecond, 0);        date  Calendartime = calendar.gettime ();         long time  = calendartime.gettime ();         //request parameter Array          object[] args = point.getargs ();         //key can be customized         String key =  jedislock.cachename.add_bean_after_check_lock_key +  ":"  + args[0];         try {            if   (Jedis != null)  {                long  Lock = jedis.setnx (key, time +  "");                 while  (lock == 0)  {                      TimeUnit.MILLISECONDS.sleep (;             )        lock = jedis.setnx (key, time +  "");                 }                 //Set timeout time                  jedis.expire (key, 3);             }            //User Business Processing             proceed = point.proceed ();             return proceed;         } catch  (throwable throwable)  {             throw new runtimeexception (Throwable);         } finally {             if  (jedis != null)  {                 jedis.del (Key);                 jedis.close ();            &nbSP;}         }    }}

4. Wrapping method using Spring AOP

6. Specific key values can be customized to include, for example: IP, TIME, etc.

   
   

Redis Implements distributed locks