本地Java连接Redis常见问题：

• bind配置请注释掉
• 保护模式设置为no
• Linux系统的防火墙设置
• redis服务器的IP地址和密码是否正确
• 忘记写访问redis的服务端口号和auth密码

集成Jedis

jedis是什么

Jedis Client是Redis官网推荐的一个面向java客户端，库文件实现了对各类API进行封装调用。

案例

1、pom.xml

<!--jedis-->
<dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId><version>4.3.1</version>
</dependency>

2、测试

public class JedisDemo
{public static void main(String[] args){//连接本地的 Redis 服务，自己的ip和端口和密码Jedis jedis = new Jedis("192.168.111.181",6379);// 如果 Redis 服务设置了密码，需要下面这行，没有就不需要jedis.auth("111111");//keySet<String> keys = jedis.keys("*");for (Iterator iterator = keys.iterator(); iterator.hasNext();) {String key = (String) iterator.next();System.out.println(key);}System.out.println("jedis.exists====>"+jedis.exists("k2"));System.out.println(jedis.ttl("k1"));//String//jedis.append("k1","myreids");System.out.println(jedis.get("k1"));jedis.set("k4","k4_redis");System.out.println("----------------------------------------");jedis.mset("str1","v1","str2","v2","str3","v3");System.out.println(jedis.mget("str1","str2","str3"));//listSystem.out.println("----------------------------------------");//jedis.lpush("mylist","v1","v2","v3","v4","v5");List<String> list = jedis.lrange("mylist",0,-1);for (String element : list) {System.out.println(element);}//setjedis.sadd("orders","jd001");jedis.sadd("orders","jd002");jedis.sadd("orders","jd003");Set<String> set1 = jedis.smembers("orders");for (Iterator iterator = set1.iterator(); iterator.hasNext();) {String string = (String) iterator.next();System.out.println(string);}jedis.srem("orders","jd002");System.out.println(jedis.smembers("orders").size());//hashjedis.hset("hash1","userName","lisi");System.out.println(jedis.hget("hash1","userName"));Map<String,String> map = new HashMap<String,String>();map.put("telphone","138xxxxxxxx");map.put("address","atguigu");map.put("email","zzyybs@126.com");//课后有问题请给我发邮件jedis.hmset("hash2",map);List<String> result = jedis.hmget("hash2", "telphone","email");for (String element : result) {System.out.println(element);}//zsetjedis.zadd("zset01",60d,"v1");jedis.zadd("zset01",70d,"v2");jedis.zadd("zset01",80d,"v3");jedis.zadd("zset01",90d,"v4");List<String> zset01 = jedis.zrange("zset01", 0, -1);zset01.forEach(System.out::println);}
}

集成Lettuce

lettuce是什么

Lettuce是一个Redis的Java驱动包，Lettuce翻译为生菜，没错，就是吃的那种生菜，所以它的Logo长这样。

Jedis 和 Lettuce 区别

案例

1、pom.xml

<!--lettuce-->
<dependency><groupId>io.lettuce</groupId><artifactId>lettuce-core</artifactId><version>6.2.1.RELEASE</version>
</dependency>

2、测试

@Slf4j
public class LettuceDemo
{public static void main(String[] args){//使用构建器 RedisURI.builderRedisURI uri = RedisURI.builder().redis("192.168.111.181").withPort(6379).withAuthentication("default","111111").build();//创建连接客户端RedisClient client = RedisClient.create(uri);StatefulRedisConnection conn = client.connect();//操作命令apiRedisCommands<String,String> commands = conn.sync();//keysList<String> list = commands.keys("*");for(String s : list) {log.info("key:{}",s);}//Stringcommands.set("k1","1111");String s1 = commands.get("k1");System.out.println("String s ==="+s1);//listcommands.lpush("myList2", "v1","v2","v3");List<String> list2 = commands.lrange("myList2", 0, -1);for(String s : list2) {System.out.println("list ssss==="+s);}//setcommands.sadd("mySet2", "v1","v2","v3");Set<String> set = commands.smembers("mySet2");for(String s : set) {System.out.println("set ssss==="+s);}//hashMap<String,String> map = new HashMap<>();map.put("k1","138xxxxxxxx");map.put("k2","atguigu");map.put("k3","zzyybs@126.com");//课后有问题请给我发邮件commands.hmset("myHash2", map);Map<String,String> retMap = commands.hgetall("myHash2");for(String k : retMap.keySet()) {System.out.println("hash  k="+k+" , v=="+retMap.get(k));}//zsetcommands.zadd("myZset2", 100.0,"s1",110.0,"s2",90.0,"s3");List<String> list3 = commands.zrange("myZset2",0,10);for(String s : list3) {System.out.println("zset ssss==="+s);}//sortSortArgs sortArgs = new SortArgs();sortArgs.alpha();sortArgs.desc();List<String> list4 = commands.sort("myList2",sortArgs);for(String s : list4) {System.out.println("sort ssss==="+s);}//关闭conn.close();client.shutdown();}
}

集成RedisTemplate（推荐使用）

连接单机

1、pom.xml

<!--SpringBoot与Redis整合依赖-->
<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>

2、yaml

# ========================redis单机=====================
spring.redis.database=0
# 修改为自己真实IP
spring.redis.host=192.168.111.185
spring.redis.port=6379
spring.redis.password=111111
spring.redis.lettuce.pool.max-active=8
spring.redis.lettuce.pool.max-wait=-1ms
spring.redis.lettuce.pool.max-idle=8
spring.redis.lettuce.pool.min-idle=0

3、Redis配置

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;@Configuration
public class RedisConfig
{/*** redis序列化的工具配置类，下面这个请一定开启配置* 127.0.0.1:6379> keys ** 1) "ord:102"  序列化过* 2) "\xac\xed\x00\x05t\x00\aord:102"   野生，没有序列化过* this.redisTemplate.opsForValue(); //提供了操作string类型的所有方法* this.redisTemplate.opsForList(); // 提供了操作list类型的所有方法* this.redisTemplate.opsForSet(); //提供了操作set的所有方法* this.redisTemplate.opsForHash(); //提供了操作hash表的所有方法* this.redisTemplate.opsForZSet(); //提供了操作zset的所有方法* @param lettuceConnectionFactory* @return*/@Beanpublic RedisTemplate<String, Object> redisTemplate(LettuceConnectionFactory lettuceConnectionFactory){RedisTemplate<String,Object> redisTemplate = new RedisTemplate<>();redisTemplate.setConnectionFactory(lettuceConnectionFactory);//设置key序列化方式stringredisTemplate.setKeySerializer(new StringRedisSerializer());//设置value的序列化方式json，使用GenericJackson2JsonRedisSerializer替换默认序列化redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());redisTemplate.setHashKeySerializer(new StringRedisSerializer());redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());redisTemplate.afterPropertiesSet();return redisTemplate;}
}

4、Service

import lombok.extern.slf4j.Slf4j;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;import javax.annotation.Resource;
import java.util.UUID;
import java.util.concurrent.ThreadLocalRandom;@Service
@Slf4j
public class OrderService
{public static final String ORDER_KEY = "order:";@Resourceprivate RedisTemplate redisTemplate;public void addOrder(){int keyId = ThreadLocalRandom.current().nextInt(1000)+1;String orderNo = UUID.randomUUID().toString();redisTemplate.opsForValue().set(ORDER_KEY+keyId,"京东订单"+ orderNo);log.info("=====>编号"+keyId+"的订单流水生成:{}",orderNo);}public String getOrderById(Integer id){return (String)redisTemplate.opsForValue().get(ORDER_KEY + id);}
}

5、Controller

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;import javax.annotation.Resource;
import java.util.concurrent.ThreadLocalRandom;@Api(tags = "订单接口")
@RestController
@Slf4j
public class OrderController
{@Resourceprivate OrderService orderService;@ApiOperation("新增订单")@RequestMapping(value = "/order/add",method = RequestMethod.POST)public void addOrder(){orderService.addOrder();}@ApiOperation("按orderId查订单信息")@RequestMapping(value = "/order/{id}", method = RequestMethod.GET)public String findUserById(@PathVariable Integer id){return orderService.getOrderById(id);}
}

6、测试

存结果后，出现反序列化问题

原因：JDK序列化方式（默认）惹的祸

org.springframework.data.redis.serializer.JdkSerializationRedisSerializer ，

默认情况下，RedisTemplate 使用该数据列化方式，我们来看下源码 RedisTemplate#afterPropertiesSet()

 解决方式：使用StringRedisTemplate

连接集群

yaml文件

# ========================redis集群=====================
spring.redis.password=111111
# 获取失败 最大重定向次数
spring.redis.cluster.max-redirects=3
spring.redis.lettuce.pool.max-active=8
spring.redis.lettuce.pool.max-wait=-1ms
spring.redis.lettuce.pool.max-idle=8
spring.redis.lettuce.pool.min-idle=0
spring.redis.cluster.nodes=192.168.111.175:6381,192.168.111.175:6382,192.168.111.172:6383,192.168.111.172:6384,192.168.111.174:6385,192.168.111.174:6386

集群存在的问题：

1、模拟节点下线：人为模拟，master-6381机器意外宕机，手动shutdown，先对redis集群命令方式，手动验证各种读写命令，6384上位替换原主节点6381。

原因：Redis Cluster集群能自动感知并自动完成主备切换，对应的slave6384会被选举为新的master节点。

2、出现经典故障：SpringBoot客户端不会动态感知到RedisCluster的最新集群信息

【故障演练】 Redis Cluster集群部署采用了3主3从拓扑结构，数据读写访问master节点， slave节点负责备份。当master宕机主从切换成功，redis手动OK，but 2个经典故障

3、导致原因

SpringBoot2.X版本，Redis默认的连接池采用Lettuce，当Redis集群节点发生变化后，Lettuce默认是不会刷新节点拓扑。

4、解决方案

• 排除lettuce采用jedis（不推荐）

 

• 重写连接工厂实例（极度不推荐）

@Beanpublic DefaultClientResources lettuceClientResources() {return DefaultClientResources.create();}@Beanpublic LettuceConnectionFactory lettuceConnectionFactory(RedisProperties redisProperties, ClientResources clientResources) {ClusterTopologyRefreshOptions topologyRefreshOptions = ClusterTopologyRefreshOptions.builder().enablePeriodicRefresh(Duration.ofSeconds(30)) //按照周期刷新拓扑.enableAllAdaptiveRefreshTriggers() //根据事件刷新拓扑.build();ClusterClientOptions clusterClientOptions = ClusterClientOptions.builder()//redis命令超时时间,超时后才会使用新的拓扑信息重新建立连接.timeoutOptions(TimeoutOptions.enabled(Duration.ofSeconds(10))).topologyRefreshOptions(topologyRefreshOptions).build();LettuceClientConfiguration clientConfiguration = LettuceClientConfiguration.builder().clientResources(clientResources).clientOptions(clusterClientOptions).build();RedisClusterConfiguration clusterConfig = new RedisClusterConfiguration(redisProperties.getCluster().getNodes());clusterConfig.setMaxRedirects(redisProperties.getCluster().getMaxRedirects());clusterConfig.setPassword(RedisPassword.of(redisProperties.getPassword()));LettuceConnectionFactory lettuceConnectionFactory = new LettuceConnectionFactory(clusterConfig, clientConfiguration);return lettuceConnectionFactory;}

• 刷新节点集群拓扑动态感应

官网：Redis Cluster · lettuce-io/lettuce-core Wiki · GitHub

改写yaml

# ========================redis集群=====================
spring.redis.password=111111
# 获取失败 最大重定向次数
spring.redis.cluster.max-redirects=3
spring.redis.lettuce.pool.max-active=8
spring.redis.lettuce.pool.max-wait=-1ms
spring.redis.lettuce.pool.max-idle=8
spring.redis.lettuce.pool.min-idle=0
#支持集群拓扑动态感应刷新,自适应拓扑刷新是否使用所有可用的更新，默认false关闭
spring.redis.lettuce.cluster.refresh.adaptive=true
#定时刷新
spring.redis.lettuce.cluster.refresh.period=2000
spring.redis.cluster.nodes=192.168.111.175:6381,192.168.111.175:6382,192.168.111.172:6383,192.168.111.172:6384,192.168.111.174:6385,192.168.111.174:6386