redis主从
Memcached完全基于分布式集群，而Redis是Master-Slave，如果想把Reids，做成集群模式，无外乎多做几套Master-Slave，每套Master-Slave完成各自的容灾处理，通过Client工具，完成一致性哈希。
PS:Memcached是在Server端完成Sharding，Redis只能依靠各个Client做Sharding。可能会在Redis 3.0系列支持Server端Sharding。
保留前面的JedisPoolConfig，新增两个Redis的IP（redis1.ip，redis2.ip），完成两个JedisShardInfo实例，并将其丢进List中：
Java代码
JedisShardInfo jedisShardInfo1 = new JedisShardInfo(
bundle.getString("redis1.ip"), Integer.valueOf(bundle .getString("redis.port")));
JedisShardInfo jedisShardInfo2 = new JedisShardInfo(
bundle.getString("redis2.ip"), Integer.valueOf(bundle .getString("redis.port")));
List<JedisShardInfo> list = new LinkedList<JedisShardInfo>();
list.add(jedisShardInfo1);
list.add(jedisShardInfo2);
初始化ShardedJedisPool代替JedisPool：
Java代码
ShardedJedisPool pool = new ShardedJedisPool(config, list);
改由ShardedJedis，获取Jedis对象：
Java代码
// 从池中获取一个Jedis对象
ShardedJedis jedis = pool.getResource();
String keys = "name";
String value = "snowolf";
// 删数据
jedis.del(keys);
// 存数据
jedis.set(keys, value);
// 取数据
String v = jedis.get(keys);
System.out.println(v);
// 释放对象池
pool.returnResource(jedis);
四、Spring封装参考
Ok，完成上述代码足够完成简单任务，如果有必要，可以用Spring封装初始化：
Xml代码
<context:property-placeholder location="classpath:redis.properties" />
<bean
id="jedisPoolConfig"
class="redis.clients.jedis.JedisPoolConfig"
>
<property
name="maxActive"
value="${redis.pool.maxActive}" />
<property
name="maxIdle"
value="${redis.pool.maxIdle}" />
<property
name="maxWait"
value="${redis.pool.maxWait}" />
<property
name="testOnBorrow"
value="${redis.pool.testOnBorrow}" />
</bean>
<bean
id="shardedJedisPool"
class="redis.clients.jedis.ShardedJedisPool"
>
<constructor-arg
index="0"
ref="jedisPoolConfig" />
<constructor-arg index="1">
<list>
<bean class="redis.clients.jedis.JedisShardInfo">
<constructor-arg
index="0"
value="${redis1.ip}" />
<constructor-arg
index="1"
value="${redis.port}"
type="int" />
</bean>
<bean class="redis.clients.jedis.JedisShardInfo">
<constructor-arg
index="0"
value="${redis2.ip}" />
<constructor-arg
index="1"
value="${redis.port}"
type="int" />
</bean>
</list>
</constructor-arg>
</bean>
view plaincopy
<context:property-placeholder location="classpath:redis.properties" />
<bean
id="jedisPoolConfig"
class="redis.clients.jedis.JedisPoolConfig"
>
<property
name="maxActive"
value="${redis.pool.maxActive}" />
<property
name="maxIdle"
value="${redis.pool.maxIdle}" />
<property
name="maxWait"
value="${redis.pool.maxWait}" />
<property
name="testOnBorrow"
value="${redis.pool.testOnBorrow}" />
</bean>
<bean
id="shardedJedisPool"
class="redis.clients.jedis.ShardedJedisPool"
>
<constructor-arg
index="0"
ref="jedisPoolConfig" />
<constructor-arg index="1">
<list>
<bean class="redis.clients.jedis.JedisShardInfo">
<constructor-arg
index="0"
value="${redis1.ip}" />
<constructor-arg
index="1"
value="${redis.port}"
type="int" />
</bean>
<bean class="redis.clients.jedis.JedisShardInfo">
<constructor-arg
index="0"
value="${redis2.ip}" />
<constructor-arg
index="1"
value="${redis.port}"
type="int" />
</bean>
</list>
</constructor-arg>
</bean>
代码可以更简洁一些：
Java代码
private ApplicationContext app;
private ShardedJedisPool pool;
@Before
public void before() throws Exception {
app = new ClassPathXmlApplicationContext("applicationContext.xml");
pool = (ShardedJedisPool) app.getBean("shardedJedisPool");
}
@Test
public void test() {
// 从池中获取一个Jedis对象
ShardedJedis jedis = pool.getResource();
String keys = "name";
String value = "snowolf";
// 删数据
jedis.del(keys);
// 存数据
jedis.set(keys, value);
// 取数据
String v = jedis.get(keys);
System.out.println(v);
// 释放对象池
pool.returnResource(jedis);
assertEquals(value, v);
}
当然，Spring提供了对于Redis的专门支持：spring-data-redis，以后有机会再深入研究。