Java 访问多级 JSON 结构中的值
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Access to the values in a multi-level JSON-structure
提问by Mark Korzhov
There is my JSON-structure:
有我的 JSON 结构：
{
"date":"19.11.2013",
"parent":{
"child1":[
{
"date":"2013-11-19",
"time":"10:30",
},
{
"date":"2013-11-19",
"time":"12:20",
}
],
"child2":[
{
"date":"2013-11-19",
"time":"10:30",
},
{
"date":"2013-11-19",
"time":"12:20",
}
]
}
}
And it's my code at the moment:
这是我目前的代码：
public class json {
public static void main(String[] args) throws IOException, ParseException {
URL urlData = new URL("http://path.to/json");
BufferedReader reader = new BufferedReader(new InputStreamReader(
urlData.openConnection().getInputStream(), "utf-8"));
String struct = reader.readLine();
JSONParser parser = new JSONParser();
Object obj = parser.parse(struct);
JSONObject lev1 = (JSONObject) obj;
System.out.println(lev1.get("date"));
}
}
I got a datevalue (19.11.2013), but I don't know how to get child's values of dateand time. I'm using json-simple library.
我得到了一个日期值（19.11.2013），但我不知道如何获取孩子的date和time值。我正在使用 json-simple 库。
采纳答案by kiruwka
Here is the idea :
这是想法：
JSONObject parent = (JSONObject) lev1.get("parent");
JSONArray child1 = (JSONArray) parent.get("child1"); // same for child2
for (Object elem : child1) {
System.out.prinlnt("date = " + ((JSONObject) elem).get("date"));
System.out.prinlnt("time = " + ((JSONObject) elem).get("time"));
}
Let me know if it does not compile, otherwise should work.
如果它不编译，请告诉我，否则应该可以工作。
回答by Jhanvi
Since, the names of the array are child1and child2(which means the names are different), inside the parent object , first you have to fetch these names, and then for each array, fetch date and time.
因为，数组的名称是child1和child2（这意味着名称不同），在父对象内部，首先您必须获取这些名称，然后对于每个数组，获取日期和时间。
Here struct, is the jsonString:
这里struct，是 jsonString：
JSONParser parser = new JSONParser();
Object obj = parser.parse(struct);
JSONObject lev1 = (JSONObject) obj;
Object jObj = lev1.get("parent");
List keys = new ArrayList();
if (jObj instanceof Map) {
Map map = (Map) jObj;
Set keySet = map.keySet();
for (Object s : keySet) {
JSONObject jsonObj = (JSONObject) jObj;
JSONArray jarr = (JSONArray) jsonObj.get(s.toString());
for (int i = 0; i < jarr.size(); i++) {
Object get = jarr.get(i);
JSONObject job = (JSONObject) get;
String date = job.get("date").toString();
String time = job.get("time").toString();
System.out.println("Date: " + date + " , Time: " + time);
}
}
}
