The use of "JSON" Jackson

All of Jackson's operations are manipulated by Objectmapper object instances, and can be reused for this object instance.

First define an instance:
ObjectMapper mapper = new ObjectMapper();

Define a Student class:

    Package Jackson;    import java.util.Date;     Public classStudent {PrivateString name;Private intAgePrivateString position;PrivateDate Createtime; PublicStringGetName() {returnName } Public void SetName(String name) { This.name= name; } Public int Getage() {returnAge } Public void Setage(intAge) { This. Age= age; } PublicStringgetPosition() {returnPosition } Public void SetPosition(String position) { This.position= position; } PublicDateGetcreatetime() {returnCreatetime; } Public void Setcreatetime(Date createtime) { This.Createtime= Createtime; }@Override         PublicStringtoString() {return "Student [name="+ name +", age="+ Age +", position="+ Position +", createtime="+ Createtime +"]"; }    }

Prepare a string:
String jsonString = "{\"name\":\"king\",\"age\":21}";

General operations: string-to-object

     mapper.readValue(jsonString,Student.class);     System.out.println(student);

Print out the results:

Student [name=king, age=21, position=null, createTime=null]

General operations: object to String

        student.setCreateTime(new Date());        String json = mapper.writeValueAsString(student);        System.out.println(json);

Print out the results:

{"name":"king","age":21,"position":null,"createTime":1524819355361}

How do I change the format of the Output date field?

Two ways: One SimpleDateFormat, the other by annotating in the attribute field
Createtime annotations in the Student.java attribute field@JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")

import com.fasterxml.jackson.annotation.JsonFormat;publicclass Student {    private String name;    privateint age;    private String position;    @JsonFormat"yyyy-MM-dd HH:mm:ss")      private Date createTime;             //省略get,set}

Print out the results:

{"name":"king","age":21,"position":null,"createTime":"2018-04-27 09:00:56"}

8-hour time difference problem: The above print results found, 8 hours less. Workaround: Increase the time zone on the annotations.

publicclass Student {    private String name;    privateint age;    private String position;    @JsonFormat"yyyy-MM-dd HH:mm:ss""GMT+8")      private Date createTime;                //省略get,set}

Print out the results:

{"name":"king","age":21,"position":null,"createTime":"2018-04-27 17:07:33"}

The use of "JSON" Jackson