Xcode解析JSON智慧强调

Question

我试图在Xcode 6中解析JSON，我的代码如下所示：

NSData *jsonClusterHealth = [NSData dataWithContentsOfURL:
                      [NSURL URLWithString:@"http://XXX.XXX.XXX.XXX:XXXX/_cluster/health?pretty=true"]];

id jsonCHealth = [NSJSONSerialization JSONObjectWithData:
                  jsonClusterHealth options:NSJSONReadingMutableContainers error:nil];
ClusterStatusLabel.text = [jsonCHealth objectForKey:@"status"];
//NumberOfNodesLabel.text = [jsonCHealth objectForKey:@"number_of_nodes"];
//ActiveShardsLabel.text = [jsonCHealth objectForKey:@"active_shards"];

所以，一切都很好，直到我取消了最后两行的注释，它用下面的错误使应用程序崩溃：

-[__NSCFNumber length]: unrecognized selector sent to instance 0xb000000000000013 2014-12-12 11:00:35.447 FnHAdmin[22139:1077781] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFNumber length]: unrecognized selector sent to instance 0xb000000000000013'

我发现原因是在json的宾语键中下划线.那么，在包含下划线的json键的Xcode中有什么问题呢？主要问题是如何修复它(我不能删除JSON中的下划线，所以解决方案必须在Xcode中).

Answer 1

从崩溃日志来看，@"number_of_nodes"和@"active_shards"键都是NSNumber类型的对象。试试看

NumberOfNodesLabel.text = [NSString stringWithFormat:@"%@", [jsonCHealth objectForKey:@"number_of_nodes"]];
ActiveShardsLabel.text = [NSString stringWithFormat:@"%@", [jsonCHealth objectForKey:@"active_shards"]];