分布式系统全局唯一id
在互联网系统中，并发越大的系统，数据就越大，数据越大就越需要分布式，而大量的分布式数据就越需要唯一标识来识别它们。
例如淘宝的商品系统有千亿级别商品，订单系统有万亿级别的订单数据，这些数据都是日渐增长，传统的单库单表是无法支撑这种级别的数据，必须对其进行分库分表；一旦分库分表，表的自增id就失去了意义；故需要一个全局唯一的id来标识每一条数据（商品、订单）。
e.g: 一张表1亿条数据，被分库分表10张表，原先的id就失去意义，所以需要全局唯一id来标识10张表的数据。
全局唯一的id生成的技术方案有很多，业界比较有名的有 uuid、redis、twitter的snowflake算法、美团leaf算法。
基于redis incr 命令生成分布式全局唯一id
incr 命令主要有以下2个特征：
- redis的incr命令具备了“incr and get”的原子操作
- redis是单进程单线程架构，incr命令不会出现id重复
基于以上2个特性，可以采用incr命令来实现分布式全局id生成。
采用redis生成商品全局唯一id
project directory
maven dependency
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<?xml version="1.0" encoding="utf-8"?><project xmlns="http://maven.apache.org/pom/4.0.0" xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xsi:schemalocation="http://maven.apache.org/pom/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <parent> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-parent</artifactid> <version>2.2.8.release</version> <relativepath/> </parent> <modelversion>4.0.0</modelversion> <groupid>org.fool.redis</groupid> <artifactid>redis-string-id</artifactid> <version>1.0-snapshot</version> <dependencies> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-web</artifactid> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-test</artifactid> <scope>test</scope> </dependency> <dependency> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-starter-data-redis</artifactid> </dependency> <dependency> <groupid>org.projectlombok</groupid> <artifactid>lombok</artifactid> <version>1.18.12</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupid>org.springframework.boot</groupid> <artifactid>spring-boot-maven-plugin</artifactid> </plugin> </plugins> </build></project> |
application.properties
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spring.application.name=redis-spring-idserver.port=8888spring.redis.host=localhostspring.redis.port=6379spring.redis.database=0spring.redis.password=spring.redis.timeout=2000spring.redis.pool.max-active=10spring.redis.pool.max-wait=1000spring.redis.pool.max-idle=10spring.redis.pool.min-idle=5spring.redis.pool.num-tests-per-eviction-run=1024spring.redis.pool.time-between-eviction-runs-millis=30000spring.redis.pool.min-evictable-idle-time-millis=60000spring.redis.pool.soft-min-evictable-idle-time-millis=10000spring.redis.pool.test-on-borrow=truespring.redis.pool.test-while-idle=truespring.redis.pool.block-when-exhausted=false |
src
application.java
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package org.fool.redis;import org.springframework.boot.springapplication;import org.springframework.boot.autoconfigure.springbootapplication;@springbootapplicationpublic class application { public static void main(string[] args) { springapplication.run(application.class, args); }} |
product.java
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package org.fool.redis.model;import lombok.data;import java.math.bigdecimal;@datapublic class product { private long id; private string name; private bigdecimal price; private string detail;} |
idgeneratorservice.java
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package org.fool.redis.service;import org.springframework.beans.factory.annotation.autowired;import org.springframework.data.redis.core.stringredistemplate;import org.springframework.stereotype.service;@servicepublic class idgeneratorservice { @autowired private stringredistemplate stringredistemplate; private static final string id_key = "id:generator:product"; public long incrementid() { return stringredistemplate.opsforvalue().increment(id_key); }} |
productcontroller.java
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package org.fool.redis.controller;import lombok.extern.slf4j.slf4j;import org.fool.redis.model.product;import org.fool.redis.service.idgeneratorservice;import org.springframework.beans.factory.annotation.autowired;import org.springframework.web.bind.annotation.postmapping;import org.springframework.web.bind.annotation.requestbody;import org.springframework.web.bind.annotation.requestmapping;import org.springframework.web.bind.annotation.restcontroller;@restcontroller@slf4j@requestmapping(value = "/product")public class productcontroller { @autowired private idgeneratorservice idgeneratorservice; @postmapping(value = "/create") public string create(@requestbody product obj) { //生成分布式id long id = idgeneratorservice.incrementid(); //使用全局id 代替数据库的自增id obj.setid(id); //取模(e.g: 这里分为8张表，海量数据可以分为1024张表)，计算表名 int table = (int) id % 8; string tablename = "product_" + table; log.info("insert to table: {}, with content: {}", tablename, obj); return "insert to table: " + tablename + " with content: " + obj; }} |
test
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curl --location --request post 'http://localhost:8888/product/create' \--header 'content-type: application/json' \--data-raw '{ "name": "car", "price": "300000.00", "detail": "lexus style"}' |
console output
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原文链接：https://www.cnblogs.com/agilestyle/p/13194027.html
