Use annotations to format date data

Scenario: The type of the entity class is the date type, and nothing is done. The return to the front end is a timestamp, but there are more than 3 0s in the back, because the front end wants seconds, and the passed is milliseconds, we need Deal with it.
Need to use @JsonSerialize annotation
defined tools

package com.imooc.untis.serializer;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;

import java.io.IOException;
import java.util.Date;

/**
 * Created by 敲代码的卡卡罗特
 * on 2018/3/3 22:01.
 */
public class Date2LongSerializer extends JsonSerializer<Date>{
    @Override
    public void serialize(Date date, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException, JsonProcessingException {
        jsonGenerator.writeNumber(date.getTime() / 1000);
    }
}

Then add this annotation on the entity class

    /** 创建时间. */
    @JsonSerialize(using = Date2LongSerializer.class)
    private Date createTime;

    /** 更新时间. */
    @JsonSerialize(using = Date2LongSerializer.class)
    private Date updateTime;