Spring整合Redis分散式鎖
阿新 • • 發佈:2021-12-02
1.導包
<spring.boot.version>2.2.6.RELEASE</spring.boot.version>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
<version>${spring.boot.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-pool2</artifactId>
<version>2.6.2</version>
</dependency>
2.工具類
@Slf4j @Component public class RedisUtils { @Autowired private StringRedisTemplate redisTemplate; /** * 上鎖 將鍵值對設定一個指定的時間timeout. * * @param key * @param timeout 鍵值對快取的時間,單位是秒 * @return 設定成功返回true,否則返回false */ public boolean tryLock(String key, String value, longtimeout) { //底層原理就是Redis的setnx方法 boolean isSuccess = redisTemplate.opsForValue().setIfAbsent(key, value); if (isSuccess) { //設定分散式鎖的過期時間 redisTemplate.expire(key, timeout, TimeUnit.SECONDS); } return isSuccess; } public void del(String... key) {if (key != null && key.length > 0) { if (key.length == 1) { redisTemplate.delete(key[0]); } else { redisTemplate.delete(CollectionUtils.arrayToList(key)); } } } public Object get (String key) { if (key != null) { return redisTemplate.opsForValue().get(key); } return null; } }
3.使用
@Scheduled(cron = "*/5 * * ? * *") public void globalStatCache (){ //-------------上分散式鎖開始----------------- InetAddress addr = null; try { addr = InetAddress.getLocalHost(); } catch (UnknownHostException e) { e.printStackTrace(); } //獲取本機ip String ip = addr.getHostAddress(); //預設上鎖時間為五小時 //此key存放的值為任務執行的ip, // redis_default_expire_time 不能設定為永久,避免死鎖 boolean lock = redisUtils.tryLock(redisKey, ip, redis_default_expire_time); log.info("============定時任務開始=============="); if (lock) { //具體程式碼......... try { Thread.sleep(1000*60); } catch (InterruptedException e) { e.printStackTrace(); } redisUtils.del(redisKey); log.info("============本次定時任務結束=============="); //三個月 }else { log.info("============獲得分散式鎖失敗======================="); ip = (String) redisUtils.get(redisKey); log.info("============{}機器上佔用分散式鎖,聚類任務正在執行=======================", ip); return; } }