使用Objective-C建立UUID

转自: http://blog.prosight.me/index.php/2010/11/670

UUID是128位的值，它可以保证唯一性。通常，它是由机器本身网卡的MAC地址和当前系统时间来生成的。

UUID是由中划线连接而成的字符串。例如：13222F23-C76A-7781-0C12-0293E3B34398.

下面这个方法可以生成UUID并以字符串的方式进行返回。

- (NSString *)createUUID

{

// Create universally unique identifier (object)

CFUUIDRef uuidObject = CFUUIDCreate(kCFAllocatorDefault);

// Get the string representation of CFUUID object.

NSString *uuidStr = (NSString *)CFUUIDCreateString(kCFAllocatorDefault, uuidObject);

// If needed, here is how to get a representation in bytes, returned as a structure

// typedef struct {

// UInt8 byte0;

// UInt8 byte1;

// …

// UInt8 byte15;

// } CFUUIDBytes;

CFUUIDBytes bytes = CFUUIDGetUUIDBytes(uuidObject);

CFRelease(uuidObject);

return uuidStr;

}