使用 Jackson 反序列化 POJO 的日期字段 - 无法正确反序列化日期字段

Question

我正在使用 Jackson 序列化和反序列化 JSON.jackson-databind - 2.11.0

我有一个 POJO class 如下：-

package PojoWithDateField;

import java.util.Date;

import com.fasterxml.jackson.annotation.JsonFormat;

public class Booking {

private String firstName;
private String lastName;

@JsonFormat(shape = JsonFormat.Shape.STRING,pattern = "DD-MM-YYYY",timezone = "Asia/Kolkata")
private Date checkin;
@JsonFormat(pattern = "DD-MM-YYYY")
private Date checkout;

public String getFirstName() {
    return firstName;
}
public void setFirstName(String firstName) {
    this.firstName = firstName;
}
public String getLastName() {
    return lastName;
}
public void setLastName(String lastName) {
    this.lastName = lastName;
}
public Date getCheckin() {
    return checkin;
}
public void setCheckin(Date checkin) {
    this.checkin = checkin;
}
public Date getCheckout() {
    return checkout;
}
public void setCheckout(Date checkout) {
    this.checkout = checkout;
}

}

我正在序列化和反序列化如下：-

package PojoWithDateField;

import java.text.SimpleDateFormat;
import java.util.Date;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class CreatePojoWithDateField {

public static void main(String[] args) throws JsonProcessingException {
    Booking booking= new Booking();
    booking.setFirstName("Amod");
    booking.setLastName("Mahajan");
    booking.setCheckin(new Date());
    booking.setCheckout(new Date());
    
    ObjectMapper objectMapper = new ObjectMapper();

    
    String s = objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(booking);
    
    System.out.println("Serialized JSON\n"+ s);
    
    
    Booking b1 = objectMapper.readValue(s, Booking.class);
    System.out.println(b1.getCheckin());
    
    SimpleDateFormat df = new SimpleDateFormat("DD-MM-YYYY");
    System.out.println(df.format(b1.getCheckin()));
}

}

Output:-

Serialized JSON
{
  "firstName" : "Amod",
  "lastName" : "Mahajan",
  "checkin" : "13-01-2021",
  "checkout" : "13-01-2021"
}
Sun Dec 27 00:00:00 IST 2020
362-12-2021

我的期望是我想要检索的任何日期。

Answer 1

你的日期模式是错误的。 它应该是dd-MM-yyyy ，而不是DD-MM-YYYY 。 您目前将天数解释为“一年中的某一天”，将年份解释为“一年中的一周”。

您可以在这里阅读更多内容： https://docs.oracle.com/en/java/javase/15/docs/api/java.base/java/text/SimpleDateFormat.html