分布式锁：业务锁和定时任务锁

一：业务锁

在代码业务逻辑加锁，防止不同业务操作相同业务表导致数据错乱，设置锁进行等待。这里锁使用的是ReentrantLock。详细的介绍可以参考：
https://blog.csdn.net/jerry11112/article/details/112375167

@Slf4j
public class MyLock {private static ConcurrentHashMap<Long, ReentrantLock> reenTranLock = new ConcurrentHashMap<>();/*** 业务加锁* @param businessId        业务id* @param lockCode          需要加锁的代码，执行完后自动解锁* @param timeOutSeconds    锁超时时间* @return**/public static <T> T lockAndUnLock(Long businessId, Supplier<T> lockCode, long timeOutSeconds) {try {//可重入公平锁：true-公平锁，false-非公平锁ReentrantLock lock = reenTranLock.putIfAbsent(businessId, new ReentrantLock(true));lock = lock != null ? lock : reenTranLock.get(businessId);//超时加锁，单位秒boolean lockSuccess = lock.tryLock(timeOutSeconds, TimeUnit.SECONDS);if (lockSuccess) {try {return lockCode.get();} catch (Exception ex) {throw ex;} finally {//解锁lock.unlock();}} else {throw new Exception("操作失败");}} catch (Exception ex) {if (ex instanceof IllegalStateException) {throw new IllegalStateException(ex.getMessage());}throw new RuntimeException(ex);}}/*** 加锁和解锁默认60S超时* @param businessId    业务id* @param lockCode      需要加锁的代码，执行完后自动解锁* @return**/public static <T> T lockAndUnLock(Long businessId, Supplier<T> lockCode) {return lockAndUnLock(businessId, lockCode, 60);}public static void main(String[] args) {Boolean a = lockAndUnLock(1L, () -> {String aaa = "111111";return true;});System.out.println(a);}
}

二：定时任务锁

当多个负载服务同时启用相同程序定时任务，需加上分布式锁，这里使用的是redis加锁。

@Slf4j
public class TaskTest {@Autowiredprivate RedisTemplate redisTemplate;@Scheduled(cron = "0 0/10 * * * ?")public void task() {//redis key名称String redisKey = "test".concat(":").concat(this.getClass().getSimpleName()).concat("task");//加上redis锁，适应分布式场景boolean setOk = redisTemplate.opsForValue().setIfAbsent(redisKey, redisKey, 10, TimeUnit.SECONDS);  //单位秒：根据不同的业务处理，自行设置大小时间if (!setOk) {log.info(redisKey + "任务已执行");return;}try {//业务逻辑处理.....} catch (Exception ex) {log.error("定时任务异常", ex.getMessage());} finally {//手动解锁redisTemplate.delete(redisKey);}}
}