十. redis java client

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　　redis主页上列出的java 客户端有JDBC-Redis JRedis Jedis三种,下面分别介绍三种客户端的优缺点及其他相关的工具.

	支持redis版本	性能	维护	推荐
JDBC-Redis		not good
JRedis	1.2.n release 2.0.0 尚未release版本	fast
Jedis	2.0.0 release	fast	actively developed	推荐

　　
　　JDBC-Redis
　　JDBC-Redis is just a JDBC wrapper for JRedis database.
If you plan on using your code with different back-ends then JDBC is a good way to go. NOTE: It is not a complete JDBC implementation and the NOSQL will bleed through.
　　If you are going to stay with Redis then I would suggest using the API, which will give you more flexibility. Use a DAO layer pattern to encapsulate your DB Access and down the road that is all you will need to change.
　　- Romain Hippeau

　　Redis syntax is completely different from standard SQL so using JDBC doesn't help encapsulating different back-ends as you suggest: I would have to write new queries anyway... – muriloq Jun 16 '10 at 14:00

　　@muriloq - but the mechanical acquiring and releasing resources is standard. – Romain Hippeau

　　
　　
　　spring wrapper
　　Spring provides a wrapper around both implementations(Jredis Jedis) and they're providing serialization/deserialization, amongst other things:

Person p = new Person("Joe", "Trader", 33);
template.convertAndSet("trader:1", p);
Person samePerson = template.getAndConvert("trader:1", Person.class);
Assert.assertEquals(p, samePerson);     

上面的方法可能已经调整,请参见最新的 http://static.springsource.org/spring-data/data-keyvalue/docs/1.0.0.M2/reference/html/#redis

　　放弃spring wrapper　　项目中本来打算使用spring wrapper,出于以下原因最终还是放弃,直接使用Jedis,等有时间在把:
　　1.spring wrapper的版本是1.0.0.M2，里面有些bug (*)
　　2.对shard的支持没有jedis好
　　3.依赖spring3.0(主要是spring3.0 core中的convert及serializer),我们目前大多项目还是采用spring2.5.6(主要)
　　4.经过多层封装后性能还是会有损耗

　　spring nosql/cross-store
　　prototype implementation allowing entities to be stored in multiple types of data stores (i.e. JPA and Neo4j or JPA and Redis etc.)
　　　　JOhm
　　JOhm is a blazingly fast Object-Hash Mapping library for Java inspired by the awesome Ohm. The JOhm OHM is a modern-day avatar of the old ORM's like Hibernate with the difference being that we are not dealing with an RDBMS here but with a NoSQL rockstar.
　　homepage:https://github.com/xetorthio/johm
　　
　　jedis pool的问题
　　在使用jedis pool时遇到了这个问题：It seems like server has closed the connection
　　原因分析：
　　1.redis server 关闭了此客户端的连接:server端设置了maxidletime(默认是5分钟），服务端会不断循环检测clinet的最后一次通信时间（lastinteraction），如果大于maxidletime，则关闭连接，并回收相关资源。client在向该连接中写数据后就会由于server端已经关闭而出现 broken pipe的问题。
　　2.pool的设置错误:



　　
        
        
        
    　　
   
        
        
   

   
   
        
        
            
               
            
        
   

   

　　上面的这种配法在spring初始化时获取一次实例化jedisCommands，而后每次的redis的调用时并未从pool中获取
　　解决方案：
　　设置



   
        
        
        
        
   

   
   
        
        
   

   
   
        
        
            
               
            
        
   
　　参考:
http://stackoverflow.com/questions/3047010/best-redis-library-for-java
https://github.com/xetorthio/johm
　　https://github.com/xetorthio/jedis/issues/closed#issue/76