BlockTest.h

#import <Foundation/Foundation.h>

typedef void (^didFinishBlock)(NSString *str);

typedef void (^didFailBlock)(NSString *str);

@interface BlockTest : NSObject

+(void)justForTest:(NSString *)string finishBlock:(didFinishBlock)finishBlock failBlock:(didFailBlock)failBlock;

@end

BlockTest.m

#import "BlockTest.h"

@implementation BlockTest

+(void)justForTest:(NSString *)string finishBlock:(didFinishBlock)finishBlock failBlock:(didFailBlock)failBlock

{

    if ([string isEqualToString:@"test"]) {

         finishBlock(string);

    }

    else

    {

        failBlock(@"参数错误");

    }

}

@end

// 使用

 [BlockTest justForTest:@"testt" finishBlock:^(NSString *str) {

       NSLog(@"%@",str);

   } failBlock:^(NSString *str) {

       NSLog(@"%@",str);

   }];