dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0) , ^{
                NSString *cachPath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask, YES) objectAtIndex:0];
                
                NSArray *files = [[NSFileManager defaultManager] subpathsAtPath:cachPath];
                NSLog(@"files :%d",[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:nilwaitUntilDone:YES];});

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