方法一：配置文件修改

修改配置文件配置application.yml：

spring:# 配置日期格式化jackson:date-format: yyyy-MM-dd HH:mm:ss  #时间戳统一转换为指定格式time-zone: GMT+8  # 时区修改为东8区

application.properties配置方式

spring.jackson.date-format=yyyy-MM-dd HH:mm:ss #时间戳统一转换为指定格式
spring.jackson.time-zone=GMT+8 # 时区修改为东8区

【注意】这里需要修改时区time-zone：数据库默认时区是格林尼治的时间，如果不设置，会比实际时间少8个小时（北京时间）。

方法二：在javabean实体类上加注解 

@JsonFormat注解

@JsonFormat注解用于属性或方法上，将Date类型转换为我们需要的类型显示。

//在pattern上设置自己需要的格式
@JsonFormat(pattern="yyyy-MM-dd HH:mm:ss")
private Date createTime;

@DateTimeFormat注解

在需要进行日期格式转换的Date属性上添加注解@DateTimeFormat(pattern = "需要转换的格式")

//注解将yyyy-MM-dd的形式转换为Date数据
@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
private Date birthday;

@Temporal注解

通过@Temporal注解，实现日期格式转换，它自带属性参数，比如：

@Entity
public class MyEntity {@Idprivate Long id;// 得到YYYY-MM-DD日期格式@Temporal(TemporalType.DATE)private Date myDate;// 得到HH:MM:SS时间格式@Temporal(TemporalType.TIME)private Date myTime;// 得到YYYY-MM-DD HH:MM:SS时间格式@Temporal(TemporalType.TIMESTAMP)private Date myTimestamp;// other fields and methods
}

 方法三：SpringBoot配置全局日期格式转换器

package com.mooding.common.share.config;import java.io.IOException;
import java.text.SimpleDateFormat;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.util.Date;import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.jackson.JsonComponent;import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.mooding.common.tools.utils.DateUtils;import lombok.SneakyThrows;/*** 类UserCombinedSerializer的实现描述**/
@JsonComponent
@ConditionalOnProperty(prefix = DateFormatConfig.PREFIX, name = "enabled", havingValue = "true", matchIfMissing = true)
public class DateFormatConfig {public static final String PREFIX = "mooding.localdateformat";/*** 中划线*/public static final String STRIKETHROUGH = "-";public static class LocalDateTimeJsonSerializer extends JsonSerializer<LocalDateTime> {@Overridepublic void serialize(LocalDateTime value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)throws IOException, JsonProcessingException {jsonGenerator.writeString(DateUtils.FMT.YYYY_MM_DD_HH_MM_SS.format(value));}}public static class LocalDateTimeJsonDeserializer extends JsonDeserializer<LocalDateTime> {@Overridepublic LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)throws IOException, JsonProcessingException {return DateUtils.FMT.YYYY_MM_DD_HH_MM_SS.parseLocalDateTime(jsonParser.getText());}}public static class DateJsonSerializer extends JsonSerializer<Date> {@Overridepublic void serialize(Date value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)throws IOException, JsonProcessingException {SimpleDateFormat sdf = new SimpleDateFormat(DateUtils.FMT.YYYY_MM_DD_HH_MM_SS.getPattern());jsonGenerator.writeString(sdf.format(value));}}public static class DateJsonDeserializer extends JsonDeserializer<Date> {@SneakyThrows@Overridepublic Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)throws IOException, JsonProcessingException {String text = jsonParser.getText();if (text.contains(STRIKETHROUGH)) {SimpleDateFormat sdf = new SimpleDateFormat(DateUtils.FMT.YYYY_MM_DD_HH_MM_SS.getPattern());return sdf.parse(jsonParser.getText());} else {// 时间戳转换return new Date(Long.parseLong(text));}}}public static class LocalDateJsonSerializer extends JsonSerializer<LocalDate> {@Overridepublic void serialize(LocalDate value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)throws IOException, JsonProcessingException {jsonGenerator.writeString(DateUtils.FMT.YYYY_MM_DD.format(value));}}public static class LocalDateJsonDeserializer extends JsonDeserializer<LocalDate> {@Overridepublic LocalDate deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)throws IOException, JsonProcessingException {return DateUtils.FMT.YYYY_MM_DD.parseLocalDate(jsonParser.getText());}}public static class LocalTimeJsonSerializer extends JsonSerializer<LocalTime> {@Overridepublic void serialize(LocalTime value, JsonGenerator jsonGenerator, SerializerProvider serializerProvider)throws IOException, JsonProcessingException {jsonGenerator.writeString(DateUtils.FMT.HH_MM_SS.format(value));}}public static class LocalTimeJsonDeserializer extends JsonDeserializer<LocalTime> {@Overridepublic LocalTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext)throws IOException, JsonProcessingException {return DateUtils.FMT.HH_MM_SS.parseLocalTime(jsonParser.getText());}}}