//本地路径协议头是file://
        //统一资源配置符
        NSURL *url = [NSURL URLWithString:@" *********** "];
        
        //encoding 编码格式
        //错误信息读取
        NSError *error=nil;
        
        NSString *read = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:&error];
        
        if (error == nil) {
            NSLog(@"read - %@",read);
        }else{
            //localizedDescription  错误详情信息
            NSLog(@"error - %@",error.localizedDescription);
        }
        
    
    }