Java 从 JSONObject 获取键和值
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Get Key and values from JSONObject
提问by user7637864
I am trying to extract Key and values from my JSONObject. But i am not able to do that. Here is the JSON:
我正在尝试从我的 JSONObject 中提取键和值。但我无法做到这一点。这是JSON：
[{"id":["5"]},{"Tech":["Java"]}]
It is a String initially. I have converted that to JSONObject using :
它最初是一个字符串。我已使用以下方法将其转换为 JSONObject：
JSONObject jsonObj = new JSONObject("[{"id":["5"]},{"Tech":["Java"]}]");
Then i am trying to get the key and value by:
然后我试图通过以下方式获取键和值：
jsonObj.getString("id");
But its giving me null. Can anyone help me out here?
但它给我空。有人可以帮我从这里出去吗？
回答by Vipin Chaudhary
Because at idyou dont have a string , you have a array of string ,
因为id你没有一个字符串，你有一个字符串数组，
so insted of doing this
jsonObj.getString("id");
所以不想这样做
jsonObj.getString("id");
do this
做这个
jsonObj.getArray("id");this will give you that array in return
jsonObj.getArray("id");这会给你那个数组作为回报
like if you have a Json Array at idthen you have to do this
就像如果你有一个 Json Arrayid那么你必须这样做
jsonObj.getJSONArray("id");
jsonObj.getJSONArray("id");
回答by wajih
Try this:
尝试这个：
try {
JSONArray jsonArr = new JSONArray("[{\"id\":[\"5\"]},{\"Tech\":[\"Java\"]}]");
for (int i = 0; i < jsonArr.length(); i++) {
JSONObject jsonObj = jsonArr.getJSONObject(i);
String k = jsonObj.keys().next();
Log.i("Info", "Key: " + k + ", value: " + jsonObj.getString(k));
}
} catch (JSONException ex) {
ex.printStackTrace();
}
回答by AG_
Parameter you are sending is JsonArray and referring to JsonObject. The Correct way is
您发送的参数是 JsonArray 并引用 JsonObject。正确的做法是
JSONObject jsonObj = new JSONObject("{'id':['5','6']},{'Tech':['Java']}");
System.out.println(jsonObj.getString("id"));
JSONArray jsonArray = new JSONArray("[{'id':['5','6','7','8']},{'Tech':['Java']}]");
System.out.println(jsonArray.length());
for(int i=0;i<jsonArray.length();i++){
System.out.println(jsonArray.getJSONObject(i).getString("id"));
}
