Java 如何检查 Json 对象中是否存在键并获取其值
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How to check if a key exists in Json Object and get its value
提问by dev90
Let say this is my JSON Object
让说这是我的 JSON Object
{
"LabelData": {
"slogan": "AWAKEN YOUR SENSES",
"jobsearch": "JOB SEARCH",
"contact": "CONTACT",
"video": "ENCHANTING BEACHSCAPES",
"createprofile": "CREATE PROFILE"
}
}
I need to know that either 'video` exists or not in this Object, and if it exists i need to get the value of this key. I have tried following, but i am unable to get value of this key.
我需要知道这个对象中是否存在“video”，如果它存在，我需要获取这个键的值。我试过跟随，但我无法获得此键的值。
containerObject= new JSONObject(container);
if(containerObject.hasKey("video")){
//get Value of video
}
采纳答案by Chetan Joshi
Use below code to find key is exist or not in JsonObject. has("key")method is used to find keys in JsonObject.
使用下面的代码来查找密钥是否存在于JsonObject. has("key")方法用于在JsonObject.
containerObject = new JSONObject(container);
//has method
if (containerObject.has("video")) {
//get Value of video
String video = containerObject.optString("video");
}
If you are using optString("key")method to get String value then don't worry about keys are existing or not in the JsonObject.
如果您正在使用optString("key")方法来获取字符串值，那么不要担心 .key 文件中是否存在键JsonObject。
回答by Er.Tyson Subba
Use:
用：
if (containerObject.has("video")) {
//get value of video
}
回答by Mukeshkumar S
containerObject = new JSONObject(container);
if (containerObject.has("video")) {
//get Value of video
}
回答by Tariq
From the structure of your source Object, I would try:
从源对象的结构中，我会尝试：
containerObject= new JSONObject(container);
if(containerObject.has("LabelData")){
JSONObject innerObject = containerObject.getJSONObject("LabelData");
if(innerObject.has("video")){
//Do with video
}
}
回答by Chetan Pushpad
Please try this one..
请试试这个..
JSONObject jsonObject= null;
try {
jsonObject = new JSONObject("result........");
String labelDataString=jsonObject.getString("LabelData");
JSONObject labelDataJson= null;
labelDataJson= new JSONObject(labelDataString);
if(labelDataJson.has("video")&&labelDataJson.getString("video")!=null){
String video=labelDataJson.getString("video");
}
} catch (JSONException e) {
e.printStackTrace();
}
回答by Rizwan
JSONObject root= new JSONObject();
JSONObject container= root.getJSONObject("LabelData");
try{
//if key will not be available put it in the try catch block your program
will work without error
String Video=container.getString("video");
}
catch(JsonException e){
if key will not be there then this block will execute
}
if(video!=null || !video.isEmpty){
//get Value of video
}else{
//other vise leave it
}
i think this might help you
我想这可能对你有帮助
回答by Pehlaj
Try
尝试
private boolean hasKey(JSONObject jsonObject, String key) {
return jsonObject != null && jsonObject.has(key);
}
try {
JSONObject jsonObject = new JSONObject(yourJson);
if (hasKey(jsonObject, "labelData")) {
JSONObject labelDataJson = jsonObject.getJSONObject("LabelData");
if (hasKey(labelDataJson, "video")) {
String video = labelDataJson.getString("video");
}
}
} catch (JSONException e) {
}
回答by Fathima km
JSONObject class has a method named "has". Returns true if this object has a mapping for name. The mapping may be NULL. http://developer.android.com/reference/org/json/JSONObject.html#has(java.lang.String)
JSONObject 类有一个名为“has”的方法。如果此对象具有名称映射，则返回 true。映射可能为 NULL。 http://developer.android.com/reference/org/json/JSONObject.html#has(java.lang.String)
