Redis系列---【分布式锁解决方案之Redisson】 - IT评测·应用市场-qidao123.com技术社区

<dependency>
<groupId>org.redisson</groupId>
<artifactId>redisson</artifactId>
<version>3.17.3</version>
</dependency>

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@Bean
public Redisson redisson(){
//redis为单机模式
Config config = new Config();
config.useSingleServer().setAddress("redis://localhost:6379").setPassword("123456");
return (Redisson) Redisson.create(config);
}

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package com.fast.controller;
import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.UUID;
import java.util.concurrent.TimeUnit;
/**
* @author hjw
* @since 2022年06月23日 11:42:00
*/
@RestController
@RequestMapping("stock")
public class StockController {
@Autowired
private RedisTemplate redisTemplate;
@Autowired
private Redisson redisson;
@GetMapping("init")
public String init() {
redisTemplate.opsForValue().set("stock", 100);
return "库存新增成功";
}
@GetMapping("sale")
public String saleGoods() {
//这样写，单机部署不会有问题，多节点就会出问题，因为synchronized只能基于jvm做加锁，多个节点属于多个jvm了
synchronized (this) {
int stock = (int) redisTemplate.opsForValue().get("stock");
if (stock > 0) {
int i = stock - 1;
redisTemplate.opsForValue().set("stock", i);
System.out.println("库存剩余:" + i);
} else {
System.out.println("库存数量不足");
return "库存数量不足";
}
}
return "库存扣减成功";
}
@GetMapping("saleImprove")
public String saleImprove() {
//使用redisson实现分布式锁
String lockKey = "product_001";
// String clientId = UUID.randomUUID().toString();
**RLock redissonLock = redisson.getLock(lockKey);**
try {
//使用redisTemplate还需要手写子线程每隔30s*1/3=10s，根据clientId给每个线程的lockKey进行续期，防止lockKey失效后，业务未执行完，结果下个线程进来了
// Boolean result = redisTemplate.opsForValue().setIfAbsent(lockKey,clientId,30, TimeUnit.SECONDS);
// if (!result){
// return "error_code";
// }
**redissonLock.lock();**//相当于setIfAbsent(lockKey,clientId,30, TimeUnit.SECONDS);
int stock = (int) redisTemplate.opsForValue().get("stock");
if (stock > 0) {
int i = stock - 1;
redisTemplate.opsForValue().set("stock", i);
System.out.println("库存剩余:" + i);
} else {
System.out.println("库存数量不足");
return "库存数量不足";
}
}finally {
**redissonLock.unlock();**
// if (clientId.equals(redisTemplate.opsForValue().get(lockKey))){
// redisTemplate.delete(lockKey);
// }
}
return "库存扣减成功";
}
}

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