redis自增

一, 引入依赖:

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId><version>2.6.5</version>
</dependency>

二, 配置信息:

spring:redis:# 地址host: localhost# 端口号port: 6379# 密码password:# 超时时间，单位毫秒timeout: 3000# 数据库编号database: 0

JedisConfig:

package org.com.spi.config;import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;@Configuration
public class JedisConfig {@Beanpublic RedisTemplate<String, String> redisTemplate(RedisConnectionFactory factory) {StringRedisTemplate template = new StringRedisTemplate(factory);//定义key序列化方式//RedisSerializer<String> redisSerializer = new StringRedisSerializer();//Long类型会出现异常信息;需要我们上面的自定义key生成策略，一般没必要//定义value的序列化方式Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);ObjectMapper om = new ObjectMapper();om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);jackson2JsonRedisSerializer.setObjectMapper(om);// template.setKeySerializer(redisSerializer);template.setValueSerializer(jackson2JsonRedisSerializer);template.setHashValueSerializer(jackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}
}

三, redis配置类RedisUtils:

package org.com.spi.utils;import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;import javax.annotation.Resource;@Component
public class RedisUtils {@Resourceprivate RedisTemplate<String, Object> redisTemplate; //这里使用的是redisTemplate/*** redis 自增* @param key 键//     * @param by 要增加几(大于0)* @return*/public long incr(String key, long delta){if(delta<0){throw new RuntimeException("递增因子必须大于0");}return redisTemplate.opsForValue().increment(key, delta);}
}

4, 编写接口controller:

@Autowired
RedisUtils redisUtils;
/*** 根据数据库ID自增生成主键* 缺点在于数据库不能集群，只能单机搞，不适合ID作为业务传递的场景*/
@PostMapping("/redisInc")
public Long redisInc(){return redisUtils.incr("generate2",1);
}

特点: redis自增仅适合单业务场景,对于多模块、复杂业务场景不太适用;另外,redis的两种持久化机制都有一定的弊端: RDB方式-宕机存在丢失的风险, AOF方式-宕机能恢复数据,但数据恢复时间较长,在并发量大的时候可能导致ID重复的情况.

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雪花算法

主要类: IdWorker

package org.com.spi.config;import org.springframework.stereotype.Component;import java.lang.management.