[SprigMVC/SpringBoot] JSON序列化专题之日期序列化问题：接口报Jackson框架错误“InvalidDefinitionException: Java 8 date/time

Posted 2023-06-01 千千寰宇

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0 序言

今日工作中遇到的一个bug。各位看官且听我娓娓道来。

1 问题描述

请求接口时，service层返回到controller层的数据结构为List<Map<Strig, Object>>，而Map中存在一个key=date，value type=java.time.LocalDate的Entry，且日志报如下错误：

InvalidDefinitionException: Java 8 date/time type `java.time.LocalDate` not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling (through reference chain: cn.xx.bd.dataservice.common.dto.CommonResponse["data"]->cn.xx.bd.dataservice.common.dto.page.v2.PageResponse["records"]->java.util.LinkedList[0]->java.util.HashMap["date"])”

2 问题分析

jackson默认不支持java8 LocalDate/LocalDateTime的序列化和反序列化，那控制台也显示了解决的办法（引入依赖com.fasterxml.jackson.datatype:jackson-datatype-jsr310，并启用对Map中"date"的entry的处理），只不过并不全。

因为 spring-mvc / spring-boot 是使用 jackson 作为 json 序列化和反序列化工具的，故只需配置 jackson 即可

3 解决方法

解决方法1 : 类型转换(`LocalDate/LocalDateTime` --> `Date`)

将实体类中的LocalDate/LocalDateTime转为Date类型

解决方法2

Step1 引入依赖(com.fasterxml.jackson.datatype:jackson-datatype-jsr310)

<dependency>
	<groupId>com.fasterxml.jackson.datatype</groupId>
	<artifactId>jackson-datatype-jsr310</artifactId>
	<version>2.11.4</version>
</dependency>

或spring-boot项目中直接引用:

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-json</artifactId>
	<version>2.3.12.RELEASE</version>
</dependency>

Step2 策略1：配置Jackson的序列化/反序列化策略 # 为特定Class Bean的字段指定Jackson的序列化策略

通过注解指定

@JsonFormat / @DateTimeFormat / @JsonDeserialize / @JsonSerialize

    @TableField("update_time")
    @ApiModelProperty("更新时间")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") //此注解用来接收字符串类型的参数封装成LocalDateTime类型
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss",timezone = "GMT+8", shape = JsonFormat.Shape.STRING) //此注解将date类型数据转成字符串响应出去
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)		// 反序列化
    @JsonSerialize(using = LocalDateTimeSerializer.class)		// 序列化
    private LocalDateTime updateTime;

    @TableField("create_time")
    @ApiModelProperty("添加时间")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm") //此注解用来接收字符串类型的参数封装成LocalDateTime类型
    @JsonFormat(pattern = "yyyy-MM-dd HH:mm",timezone = "GMT+8", shape = JsonFormat.Shape.STRING) //此注解将date类型数据转成字符串响应出去
    @JsonDeserialize(using = LocalDateTimeDeserializer.class)		// 反序列化
    @JsonSerialize(using = LocalDateTimeSerializer.class)		// 序列化
    private LocalDateTime createTime;

Step2 策略2：配置Jackson的序列化/反序列化策略 # 全局配置(MvcConfiguration)

@Configuration
public class MvcConfiguration implements WebMvcConfigurer 
    @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) 
        MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter();
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        objectMapper.registerModule(new JavaTimeModule());
        messageConverter.setObjectMapper(objectMapper);
        converters.add(0, messageConverter);

或：

Step2.1 JacksonConfiguration

import cn.xx.bd.dataservice.biz.common.constants.Constants;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalDateTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.deser.LocalTimeDeserializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalDateTimeSerializer;
import com.fasterxml.jackson.datatype.jsr310.ser.LocalTimeSerializer;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
import org.springframework.context.annotation.Bean;

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

@Configuration
public class JacksonConfiguration 

    @Bean
    public ObjectMapper objectMapper()
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        objectMapper.disable(DeserializationFeature.ADJUST_DATES_TO_CONTEXT_TIME_ZONE);
        JavaTimeModule javaTimeModule = new JavaTimeModule();

        javaTimeModule.addSerializer(LocalDateTime.class,new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(Constants.DateTime.DEFAULT_DATE_TIME_FORMAT)));
        javaTimeModule.addSerializer(LocalDate.class,new LocalDateSerializer(DateTimeFormatter.ofPattern(Constants.DateTime.DEFAULT_DATE_FORMAT)));
        javaTimeModule.addSerializer(LocalTime.class,new LocalTimeSerializer(DateTimeFormatter.ofPattern(Constants.DateTime.DEFAULT_TIME_FORMAT)));

        javaTimeModule.addDeserializer(LocalDateTime.class,new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(Constants.DateTime.DEFAULT_DATE_TIME_FORMAT)));
        javaTimeModule.addDeserializer(LocalDate.class,new LocalDateDeserializer(DateTimeFormatter.ofPattern(Constants.DateTime.DEFAULT_DATE_FORMAT)));
        javaTimeModule.addDeserializer(LocalTime.class,new LocalTimeDeserializer(DateTimeFormatter.ofPattern(Constants.DateTime.DEFAULT_TIME_FORMAT)));
        objectMapper.registerModule(javaTimeModule).registerModule(new ParameterNamesModule());
        return objectMapper;

Step2.2 Constants

public class Constants 
    public static class DateTime 
        /** 默认日期时间格式 */
        public static final String DEFAULT_DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";
        /** 默认日期格式 */
        public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";
        /** 默认时间格式 */
        public static final String DEFAULT_TIME_FORMAT = "HH:mm:ss";