@DateTimeFormat cannot accept Japanese Calendar (Wareki) [SPR-13568]

[spring-projects-issues]

Toshiaki Maki opened SPR-13568 and commented

@DateTimeFormat is really useful. However Japanese Calendar (Wareki) cannot be accepted because there is no way to specify Locale to parse explicitly.

With JDK 1.6, parsing Wareki is as follows:

DateFormat format = new SimpleDateFormat("GGGGyy.MM.dd", new Locale("ja", "JP", "JP"));
format.parse("平成27.10.13"); // -> Tue Oct 13 00:00:00 JST 2015

This format is so important in Japan especially in public sectors.

org.springframework.format.datetime.DateFormatter#createDateFormat looks taking Locale object. In my understanding, the locale to be used is decided by the HTTP request and not specified by the application.
I would like to tell the locale by new attribute of @DateTimeFormat.

Supporting Date and Time API looks more difficult because the formatter needs Chronology like following:

DateTimeFormatter.ofPattern("GGGGyy.MM.dd")
                .withChronology(JapaneseChronology.INSTANCE)
                .parse("平成27.10.13"); // -> {},Japanese resolved to Japanese Heisei 27-10-13

---

Affects: 4.1.7, 4.2.1

Issue Links:

• @DateTimeFormat's JSR-310 formatter is not strict in case of pattern [SPR-13567] #18143 @DateTimeFormat's JSR-310 formatter is not strict in case of pattern

4 votes, 5 watchers

[spring-projects-issues]

Juergen Hoeller commented

It doesn't look feasible to introduce such fixed locale/chronology mappings for the common @DateTimeFormat annotation itself. However, we have support for applying a custom chronology and time zone already: in DateTimeContextHolder, setting a corresponding thread-local DateTimeContext for a given thread. This can be applied in a Servlet Filter for example, setting and resetting it for an entire servlet request, e.g. depending on the user or the origin of the request.

Juergen

[spring-projects-issues]

Toshiaki Maki commented

Thanks.

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.datetime.standard.DateTimeContext;
import org.springframework.format.datetime.standard.DateTimeContextHolder;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.time.LocalDate;
import java.time.chrono.JapaneseChronology;
import java.util.Date;
import java.util.Locale;

@SpringBootApplication
@RestController
public class DemoWarekiApplication extends WebMvcConfigurerAdapter {

    public static void main(String[] args) {
        SpringApplication.run(DemoWarekiApplication.class, args);
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        DateTimeContext context = new DateTimeContext();
        context.setChronology(JapaneseChronology.INSTANCE);
        Locale japan = new Locale("ja", "JP", "JP");

        registry.addInterceptor(new HandlerInterceptorAdapter() {
            @Override
            public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
                DateTimeContextHolder.setDateTimeContext(context); // for java.time.LocalDate
                LocaleContextHolder.setLocale(japan); // for java.util.Date
                return true;
            }
        });
    }

    @RequestMapping(path = "/jtl")
    Object jtl(@DateTimeFormat(pattern = "GGGGyy.MM.dd") @RequestParam(name = "date") LocalDate date) {
        return date.toString();
    }

    @RequestMapping(path = "/jud")
    Object jud(@DateTimeFormat(pattern = "GGGGyy.MM.dd") @RequestParam(name = "date") Date date) {
        return date.toString();
    }
}

works well :)