4.Redis分布式连接和主从复制

Redis本身不支持分布式，通过Jedis客户端可以实现使用Redis分布式。

package com.gqshao.redis.connection;
import com.google.common.collect.Lists;
import com.gqshao.redis.utils.JedisUtils;
import org.junit.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import redis.clients.jedis.*;
import java.util.Arrays;
import java.util.List;
/**
* Jedis 独有的分布式
* 根据List中Redis顺序和key，指定固定的Redis
* 扩容时使用 Pre-Sharding
*/
public class ShardedJedisTest {
protected static Logger logger = LoggerFactory.getLogger(ShardedJedisTest.class);
private static ShardedJedisPool pool = null;
protected ShardedJedis jedis = null;
@BeforeClass
public static void createPool() {
JedisPoolConfig poolCOnfig= JedisUtils.getMyDefaultJedisPoolConfig();
// List shards = Arrays.asList(new JedisShardInfo("192.168.3.98", 6379)
// , new JedisShardInfo("192.168.3.98", 6380));
List shards = Lists.newArrayList();
JedisShardInfo info1 = new JedisShardInfo("192.168.3.98", 6379);
JedisShardInfo info2 = new JedisShardInfo("192.168.3.98", 6380);
// 添加的顺序有意义
shards.add(info1);
shards.add(info2);
pool = new ShardedJedisPool(poolConfig, shards);
}
@Before
public void getResource() {
jedis = pool.getResource();
}
@After
public void destroyJedis() {
pool.returnResource(jedis);
}
@AfterClass
public static void destroyPool() {
pool.destroy();
}
/**
* 不同的key分配根据List中的顺序，分配不同的Redis连接
*/
@Test
public void testSet() {
for (int i = 0; i <20; i++) {
try {
logger.info(i + " - " + jedis.getShard("" + i).getClient().getHost()
+ " : " + jedis.getShard(i + "").getClient().getPort());
logger.info(jedis.set("" + i, "true"));
} catch (Exception e) {
e.printStackTrace();
}
}
}
/**
* 修改List中的顺序，无法得到结果，确定该顺序是有意义的
*/
@Test
public void testGet() {
for (int i = 0; i <20; i++) {
try {
logger.info(i + " - " + jedis.getShard(i + "").getClient().getHost()
+ ":" + jedis.getShard(i + "").getClient().getPort() + " ? " + jedis.get("" + i));
} catch (Exception e) {
e.printStackTrace();
}
}
}
}

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redis的主重复制有两种方式，第一种是写在.conf配置文件中，第二种是通过命令slaveof ip port 或?slaveof no one

slaveof no one 之后，当前Redis节点提升为Master但之前数据不会丢失，所以通过程序动态的设置主从复制可以解决Redis单点故障的问题

package com.gqshao.redis.connection;
import com.gqshao.redis.utils.JedisUtils;
import org.junit.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
/**
* slaveof 和 slaveofNoOne方法可以在运行中动态设置服务器为Master或Slave
*/
public class SlaveofTest {
protected static Logger logger = LoggerFactory.getLogger(SlaveofTest.class);
private static JedisPool pool1 = null;
protected Jedis jedis1 = null;
private static JedisPool pool2 = null;
protected Jedis jedis2 = null;
@BeforeClass
public static void init() {
JedisPoolConfig poolCOnfig= JedisUtils.getMyDefaultJedisPoolConfig();
// timeout设置为0，解决JedisConnectionException
pool1 = new JedisPool(poolConfig, "192.168.3.98", 6379, 0);
pool2 = new JedisPool(poolConfig, "192.168.3.98", 6380, 0);
logger.info("----------------------create resource----------------------");
}
@AfterClass
public static void destroy() {
pool1.destroy();
pool2.destroy();
}
@Before
public void initJedis() {
jedis1 = pool1.getResource();
jedis2 = pool2.getResource();
}
@After
public void destroyJedis() {
pool1.returnResource(jedis1);
pool2.returnResource(jedis2);
}
/**
* 测试主从复制 注意设置Slave之后需要时间复制数据
*/
@Test
public void test() {
// 设置 Redis2为Redis1的slave
logger.info("jedis1 slaveof no one");
jedis1.slaveofNoOne();
logger.info("jedis2 slaveof 192.168.3.98 6379");
jedis2.slaveof("192.168.3.98", 6379);
try {
jedis2.set("key", "value");
} catch (Exception e) {
logger.warn("由于设置的原因slave为read only");
}
// 主从复制 Redis1中保存数据Redis2中可以读取
logger.info("jedis1.set mykey1 myvalue1 : " + jedis1.set("mykey1", "myvalue1"));
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
logger.info("jedis2.get mykey1: " + jedis2.get("mykey1"));
// 单点问题解决思路(思路启用Redis2为Master，Redis1为SlaveOf Redis1)
// 提升Redis2为Master，读取刚才的数据，重启Redis1，将Redis2设置为Redis1的Master
jedis2.slaveofNoOne();
// 测试值仍然存在
logger.info("jedis2.get again : " + jedis2.get("mykey1"));
// Redis2中存入数据
logger.info("jedis2.set mykey2 myvalue2 : "+jedis2.set("mykey2", "myvalue2"));
// Redis1设置为Redis2的slave
jedis1.slaveof("192.168.3.98", 6380);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
// 测试jedis1中读取数据
logger.info("jedis1.get mykey2 : " + jedis1.get("mykey2"));
logger.info("jedis1 slaveof no one");
jedis1.slaveofNoOne();
jedis1.del("mykey1", "mykey2");
jedis2.del("mykey1", "mykey2");
}
}

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