基于OC的网络请求

-(void)request{    NSString *urlstr=@"url";    NSURL*url=[NSURL URLWithString:urlstr];    //初始化一个可变请求    NSMutableURLRequest*requset=[NSMutableURLRequest requestWithURL:url];    //设置超时时间    requset.timeoutInterval=5;    [requset setCachePolicy:NSURLRequestReturnCacheDataElseLoad];    requset.HTTPMethod=@"GET";    NSURLSession*session=[NSURLSession sharedSession];    NSURLSessionDataTask*dataTask=[session dataTaskWithRequest:requset completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {        if (error==nil) {            //获取相应信息            NSString *content=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];            NSLog(@"%@",content);            @try {                //解析json                NSData*data=[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableContainers error:nil];            } @catch (NSException *exception) {                NSLog(@"解析错误00");            } @finally {            }        }else{            NSLog(@"加载失败请重新尝试");        }    }];    [dataTask resume];}