redis计数器与数量控制的实现

admin Redis

2024-03-01 0 319

命令行命令：

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：

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: