Gson dateformat to parse/output unix-timestamps

问题

I am using Gson to serialize/deserialize my pojos and currently looking for a clean way to tell Gson to parse/output date attributes as unix-timestamps. Here's my attempt:

    Gson gson = new GsonBuilder().setDateFormat("U").create();

Comming from PHP where "U" is the dateformat used to parse/output date as unix-timestamps, when running my attempt code, I am getting this RuntimeException:

Unknown pattern character 'U'

I am assuming that Gson uses SimpleDateformat under the hood which doesn't define the letter "U".

I could write a DateTypeAdapter and register it in the GsonBuilder but I am looking for a cleaner way to achieve that. Simply changing the DateFormat would be great.

回答1:

Creating a custom DateTypeAdapter was the way to go.

`MyDateTypeAdapter`

public class MyDateTypeAdapter extends TypeAdapter<Date> {
    @Override
    public void write(JsonWriter out, Date value) throws IOException {
        if (value == null)
            out.nullValue();
        else
            out.value(value.getTime() / 1000);
    }

    @Override
    public Date read(JsonReader in) throws IOException {
        if (in != null)
            return new Date(in.nextLong() * 1000);
        else
            return null;
    }
}

Don't forget to register it!

Gson gson = new GsonBuilder().registerTypeAdapter(Date.class,new MyDateTypeAdapter()).create();

回答2:

Time stamps are just long's, so you can use that in your POJO. Or use Long to get a null if the field is missing.

class myPOJO {
    Long myDate;
}

来源：https://stackoverflow.com/questions/41348055/gson-dateformat-to-parse-output-unix-timestamps

标签

android

gson

date-format

unix-timestamp