Java GSON：获取 JSONObject 下所有键的列表
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Java GSON: Getting the list of all keys under a JSONObject
提问by imthe666st
I have got GSON as a JSON parser in Java, but the keys aren't always the same.
For example. I have the following JSON:
我有 GSON 作为 Java 中的 JSON 解析器，但密钥并不总是相同的。
例如。我有以下 JSON：
{ "The Object I already know": {
"key1":"value1",
"key2":"value2",
"AnotherObject": { "anotherKey1":"anotherValue1", "anotherKey2":"anotherValue2" }
}
{ "我已经知道的对象": {
"key1":"value1",
"key2":"value2",
"AnotherObject": { "anotherKey1":"anotherValue1", "anotherKey2":"anotherValue2" }
}
I have already got the JSONObject "The Object I already know". Now I need to get all of the JSONElements for this Object, this would be "Key1", "Key2" and "AnotherObject".
Thanks in advance.
EDIT: The Output should be a String Array with all the keys for the JSONObject
我已经得到了 JSONObject“我已经知道的对象”。现在我需要获取此对象的所有 JSONElements，这将是“Key1”、“Key2”和“AnotherObject”。
提前致谢。
编辑：输出应该是一个字符串数组，其中包含 JSONObject 的所有键
采纳答案by habsq
You can use JsonParser to convert your Json into an intermediate structure which allow you to examine the json content.
您可以使用 JsonParser 将您的 Json 转换为允许您检查 json 内容的中间结构。
String yourJson = "{your json here}";
JsonParser parser = new JsonParser();
JsonElement element = parser.parse(yourJson);
JsonObject obj = element.getAsJsonObject(); //since you know it's a JsonObject
Set<Map.Entry<String, JsonElement>> entries = obj.entrySet();//will return members of your object
for (Map.Entry<String, JsonElement> entry: entries) {
System.out.println(entry.getKey());
}
回答by Raman Shrivastava
String str = "{\"key1\":\"val1\", \"key2\":\"val2\"}";
JsonParser parser = new JsonParser();
JsonObject jObj = (JsonObject)parser.parse(str);
List<String> keys = new ArrayList<String>();
for (Entry<String, JsonElement> e : jObj.entrySet()) {
keys.add(e.getKey());
}
// keys contains jsonObject's keys
回答by Jaxt0r
Since Java 8 you can use Streams as better looking alternative:
从 Java 8 开始，您可以使用 Streams 作为更好看的替代方案：
String str = "{\"key1\":\"val1\", \"key2\":\"val2\"}";
JsonParser parser = new JsonParser();
JsonObject jObj = (JsonObject) parser.parse(str);
List<String> keys = jObj.entrySet()
.stream()
.map(i -> i.getKey())
.collect(Collectors.toCollection(ArrayList::new));
keys.forEach(System.out::println);
回答by Michal Tenenberg
As of Gson 2.8.1 you can use keySet():
从 Gson 2.8.1 开始，您可以使用keySet()：
String json = "{\"key1\":\"val\", \"key2\":\"val\"}";
JsonParser parser = new JsonParser();
JsonObject jsonObject = parser.parse(json).getAsJsonObject();
Set<String> keys = jsonObject.keySet();
