在Android上使用GSON将JSON日期格式解析为String

Question

我从JSON提要中获取了很多日期.

它们看起来像这样: \/Date(1307972400000+0200)\/

我需要使用Java将这些日期解析为小时和分钟.

编辑:

这是我走了多远:

String s = dateString.replaceAll("^/Date\\(" , "");

这给了我以下输出: 1307972400000+0200)/

如何删除这个字符串的其余部分,有什么建议吗？

我希望它像这样: 1307972400000L

Answer 1

它是来自.Net服务的JSON提要.我正在使用此代码:

public class GsonHelper {
    public static Gson createWcfGson() {
        GsonBuilder gsonb = new GsonBuilder();
        gsonb.registerTypeAdapter(Date.class, new WcfDateDeserializer());
        Gson gson = gsonb.create();
        return gson;
    }

    private static class WcfDateDeserializer implements JsonDeserializer<Date>, JsonSerializer<Date> {

        public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
            String JSONDateToMilliseconds = "\\/(Date\\((.*?)(\\+.*)?\\))\\/";
            Pattern pattern = Pattern.compile(JSONDateToMilliseconds);
            Matcher matcher = pattern.matcher(json.getAsJsonPrimitive().getAsString());
            String result = matcher.replaceAll("$2");
            return new Date(new Long(result));
    }

        @Override
        public JsonElement serialize(Date date, Type arg1, JsonSerializationContext arg2) {
            return new JsonPrimitive("/Date(" + date.getTime() + ")/");
        }
    }
}

它为Date类型注册自定义序列化器和解串器.使用很简单:Gson gson = GsonHelper.createWcfGson();做你想做的事.

更新:对不起,上一个示例不适用于时区.使用Calendar时更容易考虑时区偏移.代码如下所示:

public class GsonHelper {
    public static Gson createWcfGson() {
        GsonBuilder gsonb = new GsonBuilder();
        gsonb.registerTypeAdapter(Date.class, new WcfCalendarDeserializer ());
        Gson gson = gsonb.create();
        return gson;
    }

    public static class WcfCalendarDeserializer implements JsonDeserializer<Calendar>, JsonSerializer<Calendar> {

        public Calendar deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {

            String JSONDateToMilliseconds = "\\/(Date\\((.*?)(\\+.*)?\\))\\/";
            Pattern pattern = Pattern.compile(JSONDateToMilliseconds);
            Matcher matcher = pattern.matcher(json.getAsJsonPrimitive().getAsString());
            matcher.matches();
            String tzone = matcher.group(3);
            String result = matcher.replaceAll("$2");

            Calendar calendar = new GregorianCalendar();
            calendar.setTimeZone(TimeZone.getTimeZone("GMT" + tzone));
            calendar.setTimeInMillis(new Long(result));

            return calendar;
        }

        @Override
        public JsonElement serialize(Calendar calendar, Type arg1, JsonSerializationContext arg2) {
            return new JsonPrimitive("/Date(" + calendar.getTimeInMillis() + ")/");
        }
    }
}

然后,您可以使用返回的Calendar对象获取小时和分钟(并根据需要调整时区).

calendar.get(Calendar.HOUR_OF_DAY);
calendar.get(Calendar.MINUTE);

Answer 2

我怎样才能去掉这个字符串的其余部分，有什么建议吗？

我希望它像这样：1307972400000L

严格来说，您可以获取从开头到“+”字符的子字符串。

String input = "/Date(1307972400000+0200)/";
String result = input.replaceAll("^/Date\\(" , "");
result = result.substring(0, result.indexOf('+'));
System.out.println(new Long(result));