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 {
@Bean
public 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 {
@Resource
private 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.