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[英]Is it possible to deserialize JSON property names with periods as a nested object using GSON?
[英]How can I deserialize JSON to Java Object using GSON when the JSON using dates as property names?
我有一个要使用GSON反序列化的JSON响应。 JSON结构使用日期字符串作为属性名称。 人们将如何反序列化此类代码。
{
2015-04-23: [{
seqNum: 1,
distance: 13,
start: "123 Main St"
end: "225 Broadway"
},
{seqNum: 2
distance: 21,
start: "225 Broadway"
end: "12 West St"
}
]
}
在我的回答中,我认为您可以收到这样的JSON响应:
{
"2015-04-23": [
{
"seqNum": 1,
"distance": 13,
"start": "123 Main St",
"end": "225 Broadway"
},
{
"seqNum": 2,
"distance": 21,
"start": "225 Broadway",
"end": "12 West St"
}
],
"2015-04-24": [
{
"seqNum": 1,
"distance": 13,
"start": "123 Main St",
"end": "225 Broadway"
},
{
"seqNum": 2,
"distance": 21,
"start": "225 Broadway",
"end": "12 West St"
}
]
}
因此,第一步将是创建适当的类。
class MyObject {
private List<DateMapping> dateMappings;
public MyObject(List<DateMapping> dateMappings) {
this.dateMappings = dateMappings;
}
...
}
class DateMapping {
private Date date;
private List<Sequence> sequences;
public DateMapping(Date date, List<Sequence> sequences) {
this.date = date;
this.sequences = sequences;
}
...
}
class Sequence {
private int seqNum;
private int distance;
private String start;
private String end;
...
}
现在,如何动态解析键? 答案是使用自定义解串器:
class MyObjectAdapter implements JsonDeserializer<MyObject> {
private static final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
private static final Type listSequenceType = new TypeToken<List<Sequence>>(){}.getType();
public MyObject deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
List<DateMapping> dateMappings = new ArrayList<>();
for(Map.Entry<String, JsonElement> entry : json.getAsJsonObject().entrySet()) {
try {
dateMappings.add(new DateMapping(dateFormat.parse(entry.getKey()), context.deserialize(entry.getValue(), listSequenceType)));
} catch (ParseException e) {
e.printStackTrace();
throw new RuntimeException("Can't parse the date");
}
}
return new MyObject(dateMappings);
}
}
从那里可以看到,我遍历了顶级JsonObject
每个条目,并DateMapping
为每个条目创建了一个新的DateMapping
。 然后,您只需要在Gson解析器中注册适配器就可以了。
Gson gson = new GsonBuilder().registerTypeAdapter(MyObject.class, new MyObjectAdapter()).create();
MyObject myObject = gson.fromJson(new FileReader(new File("myJson")), MyObject.class);
在上面的示例上运行将产生输出:
MyObject =>
DateMapping Thu Apr 23 00:00:00 CEST 2015, sequences=[Sequence{seqNum=1, distance=13, start='123 Main St', end='225 Broadway'}, Sequence{seqNum=2, distance=21, start='225 Broadway', end='12 West St'}]
DateMapping Fri Apr 24 00:00:00 CEST 2015, sequences=[Sequence{seqNum=1, distance=13, start='123 Main St', end='225 Broadway'}, Sequence{seqNum=2, distance=21, start='225 Broadway', end='12 West St'}]
如果只有一个条目,则可以跳过类MyObject
的创建,并获取JsonObject
的第一个条目,从该条目创建单个DateMapping
实例。
希望能帮助到你! :)
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