十. redis java client
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.
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);
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:
<bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig">
<property name="maxActive" value="20" />
<property name="maxIdle" value="10" />
<property name="maxWait" value="1000" />
</bean><!-- jedis shard信息配置 -->
<bean id="jedis.shardInfo" class="redis.clients.jedis.JedisShardInfo">
<constructor-arg index="0" value="*.*.*.*" />
<constructor-arg index="1" value="6379" />
</bean>
<!-- jedis shard pool配置 -->
<bean id="shardedJedisPool" class="redis.clients.jedis.ShardedJedisPool">
<constructor-arg index="0" ref="jedisPoolConfig" />
<constructor-arg index="1">
<list>
<ref bean="jedis.shardInfo" />
</list>
</constructor-arg>
</bean>
<bean id="jedisCommands" factory-bean="shardedJedisPool"
factory-method="getResource" />
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
<!-- POOL配置 -->
<bean id="jedisPoolConfig" class="redis.clients.jedis.JedisPoolConfig">
<property name="maxActive" value="20" />
<property name="maxIdle" value="10" />
<property name="maxWait" value="1000" />
<property name="testOnBorrow" value="true"/>
</bean>
<!-- jedis shard信息配置 -->
<bean id="jedis.shardInfo" class="redis.clients.jedis.JedisShardInfo">
<constructor-arg index="0" value="*.*.*.*" />
<constructor-arg index="1" value="6379" />
</bean>
<!-- jedis shard pool配置 -->
<bean id="shardedJedisPool" class="redis.clients.jedis.ShardedJedisPool">
<constructor-arg index="0" ref="jedisPoolConfig" />
<constructor-arg index="1">
<list>
<ref bean="jedis.shardInfo" />
</list>
</constructor-arg>
</bean>
参考:
http://stackoverflow.com/questions/3047010/best-redis-library-for-java
https://github.com/xetorthio/johm