IOS ID產生器

////  IdGenerator.m//  Copyright (c) 2014年 青島拓宇網路科技有限公司. All rights reserved.//#import "IdGenerator.h"static long long time_stamp = 0;static long long time_stamp_now = 0;static NSMutableArray *temp = NULL;static NSNumber *random_n = NULL;static NSLock *theLock = NULL;@implementation IdGenerator/* *  擷取下一個Id */+ (long long)next{        if(theLock == NULL)        theLock = [[NSLock alloc]init];        if(temp == NULL)        temp = [[NSMutableArray alloc]init];        @synchronized(theLock){        time_stamp_now = [[NSDate date] timeIntervalSince1970];        if(time_stamp_now != time_stamp){            //清空緩衝，更新時間戳記            [temp removeAllObjects];            time_stamp = time_stamp_now;        }                //判斷緩衝中是否存在當前隨機數        while ([temp containsObject:(random_n = [NSNumber numberWithLong:arc4random() % 8999 + 1000])])            ;                if ([temp containsObject:random_n]) {            return -1;        }                [temp addObject:[NSNumber numberWithLong:[random_n longValue]]];    }        return (time_stamp * 10000) + [random_n longValue];}@end

不重複的Id產生器，理論上每秒鐘最多可以產生8999條Id，實際上每秒鐘約能產生6000條Id。

轉載請標明出處：http://www.cnblogs.com/anxin1225/p/3660506.html

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