//清除本地缓存

-(void)clearCache{

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,)

                   , ^{

       NSString *cachPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask, YES)objectAtIndex:];

       NSArray *files = [[NSFileManager defaultManager] subpathsAtPath:cachPath];

       NSLog(@"files :%lu",(unsigned long)[files count]);

       for (NSString *p in files) {

           NSError *error;

           NSString *path = [cachPath stringByAppendingPathComponent:p];

           if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {

               [[NSFileManager defaultManager] removeItemAtPath:path error:&error];

           }

       }

       [self performSelectorOnMainThread:@selector(clearCacheSuccess) withObject:nil waitUntilDone:YES];

    });

}

-(void)clearCacheSuccess
{
    NSLog(@"清理成功");   
}