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Tutorial do cliente Java do Memcached usando as bibliotecas whalin.Memcached-Java-Client e googlecode.xmemcached

Publicados: 2019-09-01
Tutorial do cliente Java do Memcached usando bibliotecas whalin e googlecode.xmemcached

Este é um tutorial continuado sobre o Memcached which is distributed memory object caching server . Aqui estão os dois tutoriais anteriores antes de passar por cima deste.

  • Como instalar e configurar o Memcached
  • Tutorial do cliente Java do Memcached usando a biblioteca net.spy.spymemcached

Neste tutorial, examinaremos o cliente Java do Memcached usando as duas abordagens abaixo:

com.whalin.Memcached-Java-Client Library

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< dependency >
< groupId > com . whalin < / groupId >
< artifactId > Memcached - Java - Client < / artifactId >
< version > 3.0.2 < / version >
< / dependency >

Biblioteca com.googlecode.xmemcached

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< dependency >
< groupId > com . googlecode . xmemcached < / groupId >
< artifactId > xmemcached < / artifactId >
< version > 2.4.5 < / version >
< / dependency >

Basta adicionar essas duas dependências do maven ao arquivo pom.xml do seu projeto para obter a biblioteca em seu espaço de trabalho do Eclipse.

Aqui está um programa CrunchifyComWhalinXMemcachedClient.java completo com todos os detalhes.

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package crunchify . java . tutorials ;
 
import java . io . IOException ;
import java . util . concurrent . TimeoutException ;
 
import com . whalin . MemCached . MemCachedClient ;
import com . whalin . MemCached . SockIOPool ;
 
import net . rubyeye . xmemcached . XMemcachedClient ;
import net . rubyeye . xmemcached . exception . MemcachedException ;
 
/**
* @author Crunchify.com
* Version: 1.2.4
* Details: Use dependency com.whalin.Memcached-Java-Client and com.googlecode.xmemcached to retrieve, store Key Value pair
*         from MemCached Server
*/
 
public class CrunchifyComWhalinXMemcachedClient {
public static void main ( String [ ] args ) {
 
log ( "===================================== Approach-1: Using SpyMemcahed: https://crunchify.com/memcached-java-client-net-spy-spymemcached/ ===================================== \n" ) ;
 
log ( "===================================== Approach-2: Using com.whalin.Memcached-Java-Client =====================================\n" ) ;
implementWhalinMemcachedJavaClient ( ) ;
 
log ( "===================================== Approach-3: Using com.googlecode.xmemcached Method =====================================\n" ) ;
implementXMemCachedClient ( ) ;
 
log ( "===================================== Program Completed ===================================== \n" ) ;
 
}
 
// Approach-1: Using SpyMemcahed: https://crunchify.com/memcached-java-client-net-spy-spymemcached/
 
// Approach-2: Using com.whalin.Memcached-Java-Client
private static void implementWhalinMemcachedJavaClient ( ) {
String [ ] servers = { "localhost:11211" } ;
 
// This class is a connection pool for maintaning a pool of persistent connections to memcached servers.
// The pool must be initialized prior to use. This should typically be early on in the lifecycle of the JVM instance.
SockIOPool crunchfiyPool = SockIOPool . getInstance ( "Crunchify" ) ;
 
// Sets the minimum number of spare connections to maintain in our available pool.
crunchfiyPool . setMinConn ( 2 ) ;
 
// Sets the maximum number of spare connections allowed in our available pool.
crunchfiyPool . setMaxConn ( 20 ) ;
 
// Sets the list of all cache servers.
crunchfiyPool . setServers ( servers ) ;
 
// Sets the failover flag for the pool. If this flag is set to true, and a socket fails to connect, the pool will attempt to return a socket from
// another server if one exists.
// If set to false, then getting a socket will return null if it fails to connect to the requested server.
crunchfiyPool . setFailover ( true ) ;
 
// Sets the initial number of connections per server in the available pool.
crunchfiyPool . setInitConn ( 30 ) ;
 
// Set the sleep time between runs of the pool maintenance thread. If set to 0, then the maint thread will not be started.
crunchfiyPool . setMaintSleep ( 90 ) ;
 
// Sets the socket timeout for reads.
crunchfiyPool . setSocketTO ( 2000 ) ;
 
// Sets the aliveCheck flag for the pool. When true, this will attempt to talk to the server on every connection checkout to make sure the connection is
// still valid.
crunchfiyPool . setAliveCheck ( true ) ;
 
crunchfiyPool . initialize ( ) ;
 
// Creates a new instance of MemCachedClient accepting a passed in pool name.
MemCachedClient crunchifyWhalinClient = new MemCachedClient ( "Crunchify" ) ;
 
// Adds data to the server; only the key and the value are specified.
crunchifyWhalinClient . add ( "Java" , "Crunchify.com" ) ;
crunchifyWhalinClient . add ( "WordPress" , "WordPress.com" ) ;
crunchifyWhalinClient . add ( "Social" , "Facebook.com" ) ;
 
log ( "==> Total 3 Records added to MemCached using com.whalin.Memcached-Java-Client Method\n" ) ;
 
// Retrieve a key from the server, using a specific hash.
// If the data was compressed or serialized when compressed, it will automatically be decompressed or serialized, as appropriate..
log ( "Key: Java, Value: " + crunchifyWhalinClient . get ( "Java" ) ) ;
log ( "Key: WordPress, Value: " + crunchifyWhalinClient . get ( "WordPress" ) ) ;
log ( "Key: Social, Value: " + crunchifyWhalinClient . get ( "Social" ) ) ;
 
log ( "==> Total 3 Records Retrieved from MemCached using com.whalin.Memcached-Java-Client Method\n" ) ;
 
// Deletes an object from cache given cache key.
crunchifyWhalinClient . delete ( "Social" ) ;
log ( "==> Record deleted using com.whalin.Memcached-Java-Client Method\n" ) ;
 
log ( "Key: Social, Value: " + crunchifyWhalinClient . get ( "Social" ) ) ;
log ( "==> Failure to get record Social as we deleted that before\n" ) ;
 
}
 
// Approach-3: Using com.googlecode.xmemcached
private static void implementXMemCachedClient ( ) {
String city = "New York" ;
String city2 = "San Francisco" ;
try {
 
// XMemcached constructor,default weight is 1
XMemcachedClient xMemCachedclient = new XMemcachedClient ( "localhost" , 11211 ) ;
 
// Set a value
xMemCachedclient . set ( "Crunchify" , 3600 , city ) ;
xMemCachedclient . set ( "Twitter" , 3600 , city2 ) ;
 
// Get a value for specify key
Object myCity = xMemCachedclient . get ( "Twitter" ) ;
log ( "=====> Key: Twitter, Value: " + xMemCachedclient . get ( "Twitter" ) + "\n" ) ;
 
// Get a value for specify key (set timeout of three seconds)
myCity = xMemCachedclient . get ( "Crunchify" , 3000 ) ;
log ( "=====> Key: Crunchify, Value: " + xMemCachedclient . get ( "Crunchify" , 3000 ) + "\n" ) ;
 
// Set a new expiration time for an existing item,using default opTimeout second.
xMemCachedclient . touch ( "key" , 30 ) ;
 
xMemCachedclient . delete ( "Crunchify" ) ;
log ( "=====> Key: Crunchify, Value: " + xMemCachedclient . get ( "Crunchify" ) + "\n" ) ;
 
// delete value
xMemCachedclient . delete ( "key" ) ;
 
// let's catch all exceptions
} catch ( IOException e ) {
e . printStackTrace ( ) ;
} catch ( MemcachedException e ) {
e . printStackTrace ( ) ;
} catch ( TimeoutException e ) {
e . printStackTrace ( ) ;
} catch ( InterruptedException e ) {
e . printStackTrace ( ) ;
}
}
 
// Simple log utility
private static void log ( Object object ) {
System . out . println ( object ) ;
 
}
 
}

Certifique-se de ter o servidor Memcached instalado e funcionando.

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bash - 3.2 $ memcached - d - p 11211

Basta executar o comando acima no Eclipse para ver o resultado abaixo.

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===================================== Approach - 1 : Using SpyMemcahed : https : //crunchify.com/memcached-java-client-net-spy-spymemcached/ =====================================
 
===================================== Approach - 2 : Using com . whalin . Memcached - Java - Client =====================================
 
SLF4J : The requested version 1.7.16 by your slf4j binding is not compatible with [ 1.6 ]
SLF4J : See http : //www.slf4j.org/codes.html#version_mismatch for further details.
== > Total 3 Records added to MemCached using com . whalin . Memcached - Java - Client Method
 
Key : Java , Value : Crunchify . com
Key : WordPress , Value : WordPress . com
Key : Social , Value : Facebook . com
== > Total 3 Records Retrieved from MemCached using com . whalin . Memcached - Java - Client Method
 
18 : 27 : 35.433 [ main ] DEBUG com . whalin . MemCached . MemCachedClient - ++++ deletion of key : Social from cache was a success
== > Record deleted using com . whalin . Memcached - Java - Client Method
 
Key : Social , Value : null
== > Failure to get record Social as we deleted that before
 
===================================== Approach - 3 : Using com . googlecode . xmemcached Method =====================================
 
18 : 27 : 35.456 [ main ] INFO net . rubyeye . xmemcached . XMemcachedClient - XMemcachedClient is using Text protocol
18 : 27 : 35.491 [ main ] INFO com . google . code . yanf4j . nio . impl . SelectorManager - Creating 8 reactors . . .
18 : 27 : 35.496 [ main ] INFO com . google . code . yanf4j . core . impl . AbstractController - The Controller started at localhost / 127.0.0.1 : 0 . . .
18 : 27 : 35.509 [ Xmemcached - Reactor - 0 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - session started
18 : 27 : 35.510 [ Xmemcached - Reactor - 0 ] INFO com . google . code . yanf4j . core . impl . AbstractController - Add a session : 127.0.0.1 : 11211
18 : 27 : 35.513 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingset Crunchify 0 3600 8
New York
 
18 : 27 : 35.514 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : set Crunchify 0 3600 8
New York
 
18 : 27 : 35.514 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 34 , capacity = 34
]
18 : 27 : 35.515 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 8 bytes from channel
18 : 27 : 35.515 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingset Twitter 0 3600 13
San Francisco
 
18 : 27 : 35.515 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : set Twitter 0 3600 13
San Francisco
 
18 : 27 : 35.515 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 38 , capacity = 38
]
18 : 27 : 35.515 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 8 bytes from channel
18 : 27 : 35.516 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingget Twitter
 
18 : 27 : 35.517 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : get Twitter
 
18 : 27 : 35.517 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 13 , capacity = 13
]
18 : 27 : 35.518 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingget Twitter
 
18 : 27 : 35.518 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 40 bytes from channel
18 : 27 : 35.518 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : get Twitter
 
18 : 27 : 35.518 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 13 , capacity = 13
]
===== > Key : Twitter , Value : San Francisco
 
18 : 27 : 35.518 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 40 bytes from channel
18 : 27 : 35.519 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingget Crunchify
 
18 : 27 : 35.519 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : get Crunchify
 
18 : 27 : 35.519 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 15 , capacity = 15
]
18 : 27 : 35.519 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 36 bytes from channel
18 : 27 : 35.519 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingget Crunchify
 
18 : 27 : 35.519 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : get Crunchify
 
18 : 27 : 35.519 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 15 , capacity = 15
]
===== > Key : Crunchify , Value : New York
 
18 : 27 : 35.520 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 36 bytes from channel
18 : 27 : 35.520 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingtouch key 30
 
18 : 27 : 35.520 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : touch key 30
 
18 : 27 : 35.520 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 14 , capacity = 14
]
18 : 27 : 35.520 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 11 bytes from channel
18 : 27 : 35.520 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingdelete Crunchify
 
18 : 27 : 35.520 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : delete Crunchify
 
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 18 , capacity = 18
]
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 9 bytes from channel
18 : 27 : 35.521 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingget Crunchify
 
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : get Crunchify
 
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 15 , capacity = 15
]
===== > Key : Crunchify , Value : null
 
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 5 bytes from channel
18 : 27 : 35.521 [ main ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - After encodingdelete key
 
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG net . rubyeye . xmemcached . impl . Optimizer - Optimieze merge buffer : delete key
 
18 : 27 : 35.521 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - send buffers :
[
buffer : position = 0 , limit = 12 , capacity = 12
]
===================================== Program Completed =====================================
 
18 : 27 : 35.522 [ Xmemcached - Reactor - 2 ] DEBUG com . google . code . yanf4j . core . impl . AbstractSession - read 11 bytes from channel

Como você vê no resultado acima, é fácil recuperar e economizar valor e é uma maneira mais rápida de ter uma solução de cache central para seu aplicativo Java de produção.