一：创建 宏 文件 SynthesizeSingleton.h

SynthesizeSingleton.h#if __has_feature(objc_arc) // ARC Version#define SYNTHESIZE_SINGLETON_FOR_CLASS(classname)   \\+ (classname *)shared##classname\{\    static classname *shared##classname = nil;\    static dispatch_once_t onceToken;\    dispatch_once(&onceToken, ^{\        shared##classname = [[classname alloc] init];\    });\    return shared##classname;\}#else // Non-ARC Version#define SYNTHESIZE_SINGLETON_FOR_CLASS(classname) \static classname *shared##classname = nil; \+ (classname *)shared##classname \{ \    @synchronized(self) \    { \        if (shared##classname == nil) \        { \            shared##classname = [[self alloc] init]; \        } \    } \    return shared##classname; \} \\+ (id)allocWithZone:(NSZone *)zone \{ \@synchronized(self) \{ \if (shared##classname == nil) \{ \shared##classname = [super allocWithZone:zone]; \return shared##classname; \} \} \return nil; \} \- (id)copyWithZone:(NSZone *)zone \{ \return self; \} \- (id)retain \{ \return self; \} \- (NSUInteger)retainCount \{ \return NSUIntegerMax; \} \- (oneway void)release \{ \} \- (id)autorelease \{ \return self; \}#endif

　　二：使用

MyClass.h@interface MyClass : NSObject+(DataStorage *)sharedMyClass;@endMyClass.m#import "SynthesizeSingleton.h"@implementation MyClassSYNTHESIZE_SINGLETON_FOR_CLASS(MyClass)@end