Why is the hour wrong in a java.sql.Timestamp field annotated with Jackson's @JsonFormat?

I want to format a Timestamp field, the value is 2017-08-03 13:30:20 but in my method the hour displayed in the console is wrong? Is it a Jackson format error or does it need a custom serializer?

Java code is as follows:

package demo.bean;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.sql.Timestamp;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;


public class TimestampDemo {
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    private Timestamp time;

    public Timestamp getTime() {
        return time;
    }

    public void setTime(Timestamp time) {
        this.time = time;
    }

    public static void main(String[] args) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = null;
        try {
            date = sdf.parse("2017-08-03 13:30:20");
        } catch (ParseException e) {
            e.printStackTrace();
        }
        TimestampDemo demo = new TimestampDemo();
        demo.setTime(new Timestamp(date.getTime()));
        ObjectMapper mapper = new ObjectMapper();
        try {
                    System.out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString((demo)));

        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        System.out.println(Locale.getDefault());
        System.out.println(TimeZone.getDefault());
   }
}

console log is

{
  "time" : "2017-08-03 05:30:20"
}
zh_CN
sun.util.calendar.ZoneInfo[id="Asia/Shanghai",offset=28800000,dstSavings=0,useDaylight=false,transitions=19,lastRule=null]

if date is 2017-08-03 7:30:20 console time is 2017-08-02 23:30:20,

if date is 2017-08-03 8:00:00 console time is 2017-08-03 00:00:00,

It's 8 hours too early, is it a timezone or locale problem?