来自Spring的Json响应中的时区问题

Question

我在JSON输出中显示日期时遇到问题。在代码中我使用java.util.Date，它的值是2019-03-07但在JSON中我得到了2019-03-06 23:00:00。我认为问题出在时区，但我也没有在数据库和代码中使用时区。

我试图修复它

@JsonFormat(pattern = "yyyy-MM-dd hh:mm:ss", timezone="UTC")

和

@JsonFormat(pattern = "yyyy-MM-dd hh:mm:ss", timezone="Europe/Warsaw")

第一个没有帮助，第二个帮助但我不接受这个解决方案。

我控制器的一部分：

return new ThisDay(
    sysoperMgr.getToday(),
    new Date()
);

这是我回来的对象。

@Getter
@Setter
public class ThisDay {

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    Date dataZamkniecia;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    Date dataSystemowa;

    public BiezacaDoba(Date dataZamkniecia, Date dataSystemowa) {
        this.dataZamkniecia = dataZamkniecia;  // cdate = 2019-03-07T00:00:00.000+0100
        this.dataSystemowa = dataSystemowa; // cdate = 2019-03-27T16:08:12.343+0100
    }
}

此函数获取日期：

public Date getToday() {

    Timestamp timestamp = sysoperDao.getDataOstatniejZamknietejDoby(); // cdate = 2019-03-06T00:00:00.000+0100
    java.util.Date lastDay = new java.sql.Date(misc.roundTimestamp(timestamp).getTime()); // cdate = 2019-03-06T00:00:00.000+0100
    java.util.Date thisDay = misc.incrementDate(ostatniaDoba, Increment.DAILY, 1); // cdate = 2019-03-07T00:00:00.000+0100
    return thisDay;
}

Json结果：

{
  "dataZamkniecia":"2019-03-06 23:00:00",
  "dataSystemowa": "2019-03-27 15:12:15"
}

如何让JSON始终在本地时区显示日期？

Answer 1

Date是过时的类，不应该使用，因为Java 8发布java.time包或我们可以使用Joda-Time。您将日期从Timestamp转换为java.sql.Date，然后转换为java.util.Date。这是非常不安全的，见下面的例子：

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;

import java.time.LocalDate;
import java.time.ZoneId;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class JsonApp {

    public static void main(String[] args) throws Exception {
        ObjectMapper mapper = new ObjectMapper();
        mapper.enable(SerializationFeature.INDENT_OUTPUT);

        // Java time precise dates
        LocalDate localDateOpened = LocalDate.of(2019, 03, 07);
        LocalDate localDateClosed = localDateOpened.plusDays(20);

        ZoneId utc = ZoneId.of("UTC");
        Date opened = Date.from(localDateOpened.atStartOfDay(utc).toInstant());
        Date closed = Date.from(localDateClosed.atStartOfDay(utc).toInstant());

        System.out.println("Dates generated from java.time.*");
        System.out.println(mapper.writeValueAsString(new ThisDay(opened, closed)));

        // Calculate dates with default timezone
        Calendar calendar = Calendar.getInstance();
        opened = calendar.getTime();
        calendar.add(Calendar.DAY_OF_MONTH, 20);
        closed = calendar.getTime();

        System.out.println("Dates generated from Calendar");
        System.out.println(mapper.writeValueAsString(new ThisDay(opened, closed)));

        // Calculate dates with UTC timezone
        calendar = Calendar.getInstance();
        calendar.setTimeZone(TimeZone.getTimeZone(utc));
        calendar.set(Calendar.MILLISECOND, 0); // Recompute

        opened = calendar.getTime();
        calendar.add(Calendar.DAY_OF_MONTH, 20);
        closed = calendar.getTime();

        System.out.println("Dates generated from UTC Calendar");
        System.out.println(mapper.writeValueAsString(new ThisDay(opened, closed)));
    }
}

class ThisDay {

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date opened;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Date closed;

    public ThisDay(Date opened, Date closed) {
        this.opened = opened;
        this.closed = closed;
    }

    public Date getOpened() {
        return opened;
    }

    public void setOpened(Date opened) {
        this.opened = opened;
    }

    public Date getClosed() {
        return closed;
    }

    public void setClosed(Date closed) {
        this.closed = closed;
    }
}

上面的代码打印：

Dates generated from java.time.*
{
  "opened" : "2019-03-07 00:00:00",
  "closed" : "2019-03-27 00:00:00"
}
Dates generated from Calendar
{
  "opened" : "2019-03-27 23:45:12",
  "closed" : "2019-04-16 22:45:12"
}
Dates generated from UTC Calendar
{
  "opened" : "2019-03-28 00:45:12",
  "closed" : "2019-04-17 00:45:12"
}

请注意，第二和第三个opened日期有一个小时的差异。我手动将日历时区设置为UTC并强制重新计算设置毫秒到0的值：

calendar.setTimeZone(TimeZone.getTimeZone(utc));
calendar.set(Calendar.MILLISECOND, 0); // Recompute

这就是Date过时的原因，应该使用java.time包。如果你不想显示时间，只有日期 - 更改格式为@JsonFormat(pattern = "yyyy-MM-dd")。

也可以看看：

• Spring Boot Jackson date and timestamp Format