NSString *signValue = [NSString stringWithFormat:@"%@%@", valueJson, [Utility getCurrentTimes]];

NSMutableString * getSignString = [NSMutableString string];

NSMutableArray * mutaArray = [NSMutableArray array];

for (int i = 0; i < [signValue length]; i ++) {

[mutaArray addObject:[signValue substringWithRange:NSMakeRange(i, 1)]];

}

NSStringCompareOptions comparisonOptions = NSCaseInsensitiveSearch|NSNumericSearch|

NSWidthInsensitiveSearch|NSForcedOrderingSearch;

NSComparator sort = ^(NSString *obj1,NSString *obj2){

NSRange range = NSMakeRange(0,obj1.length);

return [obj1 compare:obj2 options:comparisonOptions range:range];

};

NSArray *resultArray2 = [mutaArray sortedArrayUsingComparator:sort];

for (NSString * oldString in resultArray2) {

[getSignString appendString:oldString];

}

//signValue為輸入字符串， getSignString為最後得到字符串

iOS 對字符串進行ASCII碼排序