redis计数器与数量控制

命令行命令:

java 复制代码
127.0.0.1:6379> exists mycounter
(integer) 0
127.0.0.1:6379> set mycounter 99 //设置一个值
OK
127.0.0.1:6379> get mycounter  //获得一个值
"99"
127.0.0.1:6379> incr mycounter //对计数器进行增加操作
(integer) 100
127.0.0.1:6379> get mycounter
"100"
127.0.0.1:6379> incrby mycounter 2 //对计数器进行+2操作
(integer) 102
127.0.0.1:6379> get mycounter
"102"
127.0.0.1:6379> incrby mycounter -2 //对计数器进行-2操作
(integer) 100
127.0.0.1:6379> get mycounter
"100"
127.0.0.1:6379> setnx mycounter 99 //当Key不存在时,设置这个值
(integer) 0
127.0.0.1:6379> setnx mycounter1 99  //当Key不存在时,设置这个值
(integer) 1
127.0.0.1:6379> get mycounter1 
"99"
127.0.0.1:6379> get mycounter
"100"
127.0.0.1:6379> expire mycounter 30 //设置key的生存时间
(integer) 1
127.0.0.1:6379> ttl mycounter //获得key的生存时间
(integer) 19
127.0.0.1:6379> ttl mycounter
(integer) -1
127.0.0.1:6379> exists mycounter
(integer) 1
127.0.0.1:6379> ttl mycounter
(integer) -1

数量控制器应用场景:

  • 商品抢购
  • 抽奖限量
  • 抢红包

++改进:++


java 复制代码
package com.example.demo.controller;

import com.example.demo.util.ResponseUtils;
import com.example.demo.util.dto.Data;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.Objects;
import java.util.concurrent.TimeUnit;


@RestController
@RequestMapping(value = "/demo")
@Slf4j
public class DemoController {

    @Autowired
    private ValueOperations<String, String> strOperations;
    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private ValueOperations<String, Integer> intOperations;
    @Autowired
    private RedisTemplate<String, Integer> intRedisTemplate;

    public static final String PREFIX = "mycounter_";


    @GetMapping("/v2")
    @ApiOperation(value = "方法v2")
    public ResponseEntity<Data<String>> demoV2() {


        // 2.保存数据
        strOperations.set("name", "imooc2");
        // 3. 获取数据
        String value = strOperations.get("name");


        log.info("记个日志:{}", value);
        return ResponseUtils.res(value);
    }

    @GetMapping("/v3")
    @ApiOperation(value = "方法v3")
    public ResponseEntity<Data<String>> demoV3() {


        // 2.保存数据
        stringRedisTemplate.opsForValue().set("name", "imooc3");
        // 3. 获取数据
        String value = stringRedisTemplate.opsForValue().get("name");


        log.info("记个日志:{}", value);
        return ResponseUtils.res(value);
    }

    /**
     * 数量控制器v1
     *
     * @return
     */
    @GetMapping("/count/v1")
    @ApiOperation(value = "数量控制器v1")
    public ResponseEntity<Data<String>> countV1() {
        String key = PREFIX + "v1";
        int amountLimit = 100;
        int incrAmount = 1;

        if (Objects.isNull(intOperations.get(key))) {
            intOperations.set(key, 95);
        }

        Integer currAmount = intOperations.get(key);

        if (currAmount + incrAmount > amountLimit) {
            log.info(" Bad Luck :{},{},currAmount + incrAmount > amountLimit={}", key, amountLimit,currAmount + incrAmount > amountLimit);

        } else {
            intOperations.set(key, currAmount + incrAmount);
            log.info(" Good Luck :{},{},currAmount + incrAmount > amountLimit={}", key, amountLimit,currAmount + incrAmount > amountLimit);
        }

        return ResponseUtils.res(currAmount.toString());
    }

    /**
     * 数量控制器v2
     *
     * @return
     */
    @GetMapping("/count/v2")
    @ApiOperation(value = "数量控制器v2")
    public ResponseEntity<Data<String>> countV2() {
        String key = PREFIX + "v2";
        int amountLimit = 100;
        Long incrAmount = 1L;
        int startValue = 95;
        if (!intRedisTemplate.hasKey(key)) {
            intRedisTemplate.opsForValue().setIfAbsent(key, startValue);
        }

        Integer currAmount = intRedisTemplate.opsForValue().get(key);
        Long increment = intRedisTemplate.opsForValue().increment(key, incrAmount);
        if (increment.intValue() > amountLimit) {
            log.info(" Bad Luck :{},{}", key, amountLimit);
        } else {
            log.info(" Good Luck :{},{}", key, amountLimit);
        }

        return ResponseUtils.res(currAmount.toString());
    }

}

利用apipost向v1发送请求:

向v2发送请求:


视频学习地址

相关推荐
王佑辉10 分钟前
【redis】redis缓存和数据库保证一致性的方案
redis·面试
GIS程序媛—椰子28 分钟前
【Vue 全家桶】7、Vue UI组件库(更新中)
前端·vue.js
DogEgg_00135 分钟前
前端八股文(一)HTML 持续更新中。。。
前端·html
ZL不懂前端37 分钟前
Content Security Policy (CSP)
前端·javascript·面试
木舟100941 分钟前
ffmpeg重复回听音频流,时长叠加问题
前端
Karoku0661 小时前
【企业级分布式系统】Zabbix监控系统与部署安装
运维·服务器·数据库·redis·mysql·zabbix
王大锤43911 小时前
golang通用后台管理系统07(后台与若依前端对接)
开发语言·前端·golang
gorgor在码农1 小时前
Redis 热key总结
java·redis·热key
想进大厂的小王1 小时前
项目架构介绍以及Spring cloud、redis、mq 等组件的基本认识
redis·分布式·后端·spring cloud·微服务·架构
Java 第一深情1 小时前
高性能分布式缓存Redis-数据管理与性能提升之道
redis·分布式·缓存