Redis implement a simple version of distributed locks

Principle:

Gets the specified name key if present, if there is no key, if there is no value assigned to the key, then set the expiration time;

The logic to unlock deletes the key.

1. Custom class

Package com.xxx.cloud.assets.redis.lock;
Import java.util.Collections;
Import Java.util.UUID;

Import Java.util.concurrent.TimeUnit;
Import Org.springframework.data.redis.core.RedisTemplate;

Import Org.springframework.data.redis.core.script.DefaultRedisScript; 

    /** * Each time you use, to new lock use/public class Redislock {//Lock name private String lockname;

    Lock timeout private long time;

    private static final String Key_prefix = "Businessname:lock:";

    Private long Randomvalue;

    Private Defaultredisscript Redisscript;

    Private Redistemplate redistemplate;

    Private Boolean locked; Private Redislock (String lockname, long time, Redistemplate redistemplate, Defaultredisscript redisscript) {this.
        Lockname = Key_prefix + lockname;
        This.time = time;
        This.redistemplate = redistemplate;
        This.redisscript = Redisscript;
    This.randomvalue = Uuid.randomuuid (). Getleastsignificantbits (); } public static Redislock NewredisLock (String lockname, Long, redistemplate redistemplate, Defaultredisscript redisscript) {return
    New Redislock (Lockname, Time, Redistemplate, redisscript); public Boolean Trylock () {Boolean success = Redistemplate.opsforvalue (). Setifabsent (Lockname, Randomvalue)
        ;
        Setifabsent corresponding to Redis setnx method locked = success;
        if (success) {Redistemplate.expire (Lockname, Time, timeunit.seconds);
    return success; public void UnLock () {if (locked) {Redistemplate.execute (Redisscript, collections.singletonlist
        (Lockname), randomvalue);
 }

    }

}

2. Test code

Package com.xxx.cloud.assets.service;
Import Com.xxx.cloud.assets.redis.lock.RedisLock;
Import Com.xxx.cloud.assets.test.TestBase;
Import Org.junit.Test;
Import Org.springframework.data.redis.core.RedisTemplate;

Import Org.springframework.data.redis.core.script.DefaultRedisScript;
Import Javax.annotation.Resource;
Import Java.util.concurrent.ExecutorService;
Import java.util.concurrent.Executors;

Import Java.util.concurrent.TimeUnit; public class Testredislock extends Testbase {@Resource (name = "Redistemplate") Private redistemplate Redistempla

    Te

    @Resource (name = "Dellockscript") private defaultredisscript dellockscript; @Test public void Testredislock () throws Interruptedexception {Redislock lock = Redislock.newredislock ("Test"
        , 1000,redistemplate,dellockscript);
            try {Boolean success = Lock.trylock ();
        SYSTEM.OUT.PRINTLN (Success);
        }finally {lock.unlock (); }} @Test Publicvoid Testmulredislock () throws interruptedexception {final Redislock lock1 = Redislock.newredislock ("Test", 1000,r
        Edistemplate,dellockscript);
        Final Redislock Lock2 = Redislock.newredislock ("Test", 1000,redistemplate,dellockscript); Runnable Task1 = new Runnable () {@Override public void run () {try {bool
                    EAN success = Lock1.trylock ();
                    System.out.println ("Task1" + success);
                TimeUnit.SECONDS.sleep (10);
                }catch (Exception e) {e.printstacktrace ();
                finally {Lock1.unlock ();

        }
            }
        }; Runnable task2 = new Runnable () {@Override public void run () {try {bool
                    EAN success = Lock2.trylock ();
                    System.out.println ("Task2" +success);
               TimeUnit.SECONDS.sleep (10); }catch (Exception e) {e.printstacktrace ();
                finally {Lock2.unlock ();

        }
            }
        };
        Executorservice Executorservice = Executors.newcachedthreadpool ();
        Executorservice.submit (TASK1);
        Executorservice.submit (TASK2);
    TimeUnit.SECONDS.sleep (15);
 }
}

3.spring part of the configuration

<bean id= "Redistemplate" class= "org.springframework.data.redis.core.RedisTemplate" >
		<property name= " ConnectionFactory "ref=" jedisconnectionfactory "/>
		<property name=" Defaultserializer ">
			<bean class= "Org.springframework.data.redis.serializer.StringRedisSerializer"/>
		</property>
</ bean>

<bean id= "Dellockscript" class= "Org.springframework.data.redis.core.script.DefaultRedisScript" >
		<property name= "Location" value= "Classpath:database/dellock.lua"/> <property name=
		" Resulttype "value=" Java.lang.Boolean "/>
</bean>

4.dellock.lua script (can also be replaced with code logic)

If Redis.call ("Get", keys[1]) = = Argv[1] then return
	redis.call ("Del", Keys[1])
else return
	0