【发布时间】：2015-04-01 17:59:19
【问题描述】：
我正在使用 Java 进行编码，并且正在使用 minimal-json 库。我正在尝试从 json 文本中获取一些信息（如果是数组，则为 idk）。
我正在尝试访问“流”中的“游戏”值，但我总是因空指针或解析异常而崩溃。
这是我想要获取的 json 字符串（来自 Twitch Api）：
{"_links":{"self":"https://api.twitch.tv/kraken/streams/hackerc0w","channel":"https://api.twitch.tv/kraken/channels/hackerc0w"},"stream":{"_id":13817896816,"game":"Programming","viewers":13,"created_at":"2015-04-01T13:54:54Z","video_height":1080,"average_fps":59.9235368156,"_links":{"self":"https://api.twitch.tv/kraken/streams/hackerc0w"},"preview":{"small":"http://static-cdn.jtvnw.net/previews-ttv/live_user_hackerc0w-80x45.jpg","medium":"http://static-cdn.jtvnw.net/previews-ttv/live_user_hackerc0w-320x180.jpg","large":"http://static-cdn.jtvnw.net/previews-ttv/live_user_hackerc0w-640x360.jpg","template":"http://static-cdn.jtvnw.net/previews-ttv/live_user_hackerc0w-{width}x{height}.jpg"},"channel":{"_links":{"self":"https://api.twitch.tv/kraken/channels/hackerc0w","follows":"https://api.twitch.tv/kraken/channels/hackerc0w/follows","commercial":"https://api.twitch.tv/kraken/channels/hackerc0w/commercial","stream_key":"https://api.twitch.tv/kraken/channels/hackerc0w/stream_key","chat":"https://api.twitch.tv/kraken/chat/hackerc0w","features":"https://api.twitch.tv/kraken/channels/hackerc0w/features","subscriptions":"https://api.twitch.tv/kraken/channels/hackerc0w/subscriptions","editors":"https://api.twitch.tv/kraken/channels/hackerc0w/editors","videos":"https://api.twitch.tv/kraken/channels/hackerc0w/videos","teams":"https://api.twitch.tv/kraken/channels/hackerc0w/teams"},"background":null,"banner":null,"broadcaster_language":"en","display_name":"hackerc0w","game":"Programming","logo":null,"mature":false,"status":"Coding a Chatbot in C","partner":false,"url":"http://www.twitch.tv/hackerc0w","video_banner":null,"_id":41236491,"name":"hackerc0w","created_at":"2013-03-11T17:08:22Z","updated_at":"2015-04-01T17:17:44Z","delay":0,"followers":28,"profile_banner":null,"profile_banner_background_color":null,"views":2948,"language":"de"}}}
如果主播在直播，我得到的方式是这样的：
public static boolean isStreamLive(String channel) {
try {
URL url = new URL(TWITCH_STREAM.replace("$c$", channel)) );
URLConnection conn = url.openConnection();
BufferedReader br = new BufferedReader( new InputStreamReader( conn.getInputStream() ));
String inputLine = br.readLine();
br.close();
JsonObject jsonObj = JsonObject.readFrom(inputLine);
return ( jsonObj.get("stream").isNull() )?false:true;
} catch (IOException e) {
return false;
}
}
我主要是尝试复制上面的方法。但是我一直在检查图书馆的文档以了解并且我一直在尝试很多东西。
最后是这样的：
public static String checkGame(String channel) {
if (!isStreamLive(channel)) return "El Estreamer esta Offline!";
try {
URL url = new URL( insertChannel(TWITCH_STREAM, channel) );
URLConnection conn = url.openConnection();
BufferedReader br = new BufferedReader( new InputStreamReader( conn.getInputStream() ));
String inputLine = br.readLine();
br.close();
JsonObject object = JsonObject.readFrom(inputLine);
JsonValue value = object.get("stream").asObject();
String msg = value.valueOf("status").toString();
return msg;
} catch (IOException e) {
return "Algo raro paso :/ error: 3";
}
return channel;
}
【问题讨论】：
-
顺便说一句，忽略频道，不是我的频道，是朋友
-
崩溃的那一行是我得到的值，还有编辑
-
感谢@azurefrog 进行编辑
标签： java json api twitch minimal-json