java gson 无法使用 GsonBuilder.setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ") 解析
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gson fails to parse using GsonBuilder.setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ")
提问by Elad Benda2
I get this string from the server:
我从服务器得到这个字符串：
[
{
"title":"spoil the ones u love today",
"startDateTime":"2014-08-10T20:10:36.7158Z"
},
{
"title":"home made patisserie",
"startDateTime":"2014-08-10T20:08:45.0218Z"
}
]
and I try to parse it an object
我尝试将它解析为一个对象
public class Offer implements Serializable {
public String title;
public Date startDateTime;
}
Type collectionType = new TypeToken<ArrayList<Offer>>() {}.getType();
mOffersList.addAll((Collection<? extends Offer>) gson.fromJson(result, collectionType));
but when I define "startDate" as a Date
但是当我将“startDate”定义为日期时
the collection I get back from gson is empty
我从 gson 回来的收藏是空的
When i define "startDate" as a String
当我将“startDate”定义为字符串时
the collection is filled correctly.
该集合已正确填充。
I want to change its date format. That's why I prefer saving it as a Date object.
我想改变它的日期格式。这就是为什么我更喜欢将它保存为 Date 对象的原因。
I have tried
我努力了
Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ").create;
Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ").create;
and yet Gson fails to parse the server's string into
但是 Gson 无法将服务器的字符串解析为
Date startDateTime. Nothing is added to the mOffersListand it stays empty.
Date startDateTime. 没有添加任何内容mOffersList并且它保持为空。
What am I doing wrong?
我究竟做错了什么？
回答by Vaibhav Raj
Only setting the required DateFormat is not sufficient.
仅设置所需的 DateFormat 是不够的。
You need to define an implementation of com.google.gson.JsonDeserializer. For ex.
您需要定义com.google.gson.JsonDeserializer的实现。例如。
import java.lang.reflect.Type;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
public class DateDeserializer implements JsonDeserializer<Date> {
@Override
public Date deserialize(JsonElement element, Type arg1, JsonDeserializationContext arg2) throws JsonParseException {
String date = element.getAsString();
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
format.setTimeZone(TimeZone.getTimeZone("GMT"));
try {
return format.parse(date);
} catch (ParseException exp) {
System.err.println("Failed to parse Date:", exp);
return null;
}
}
}
and then register the above deserializer:
然后注册上面的解串器：
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(Date.class, new DateDeserializer());
