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一.BUG 描述

1.现象

com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type java.util.Date from String “2023-11-30 22:31:23”: not a valid representation (error: Failed to parse Date value ‘2023-11-30 22:31:23’: Cannot parse date “2023-11-30 22:31:23”: while it seems to fit format ‘yyyy-MM-dd’T’HH:mm:ss.SSSX’, parsing fails (leniency? null))
at [Source: (StringReader); line: 1, column: 634] (through reference chain: com.kwan.springbootkwan.entity.csdn.BusinessInfoResponse[“data”]->com.kwan.springbootkwan.entity.csdn.BusinessInfoResponse$ArticleData["list"]->java.util.ArrayList[0]->com.kwan.springbootkwan.entity.csdn.BusinessInfoResponse$ArticleData$Article[“postTime”])
at com.fasterxml.jackson.databind.exc.InvalidFormatException.from(InvalidFormatException.java:67)

2.原因

实体类是 Date 类型,但是 json 字符串是 yyyy-MM-dd’T’HH:mm:ss.SSSX 的时间字段,时间格式不匹配导致,json 字符串转实体类失败了。

二.解决方案

1.添加依赖

<dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-annotations</artifactId><version>2.8.8</version>
</dependency><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.8.8</version>
</dependency><dependency><groupId>org.codehaus.jackson</groupId><artifactId>jackson-mapper-asl</artifactId><version>1.9.13</version>
</dependency>

2.添加注解

添加@JsonFormat 注解,指定时间格式为 yyyy-MM-dd HH:mm:ss 就不会报错了,

@TableField(value = "postTime")
@ApiModelProperty(value = "时间")
@JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
public Date postTime;

三.全局配置

1.@JsonComponent

@JsonFormat 注解并不能完全做到全局时间格式化，使用 @JsonComponent 注解自定义一个全局格式化类，分别对 Date 和 LocalDate 类型做格式化处理。

@JsonComponent
public class DateFormatConfig {@Value("${spring.jackson.date-format:yyyy-MM-dd HH:mm:ss}")private String pattern;@Beanpublic Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilder() {return builder -> {TimeZone tz = TimeZone.getTimeZone("UTC");DateFormat df = new SimpleDateFormat(pattern);df.setTimeZone(tz);builder.failOnEmptyBeans(false).failOnUnknownProperties(false).featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS).dateFormat(df);};}@Beanpublic LocalDateTimeSerializer localDateTimeDeserializer() {return new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(pattern));}@Beanpublic Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {return builder -> builder.serializerByType(LocalDateTime.class, localDateTimeDeserializer());}
}

2.自定义

但还有个问题，实际开发中如果我有个字段不想用全局格式化设置的时间样式,那该怎么处理呢?

@Data
public class OrderDTO {@JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd")private LocalDateTime createTime;@JsonFormat(locale = "zh", timezone = "GMT+8", pattern = "yyyy-MM-dd")private Date updateTime;
}

@JsonFormat注解的优先级比较高，会以@JsonFormat注解的时间格式为主。

3.@Configuration

注意：在使用此种配置后，字段手动配置@JsonFormat 注解将不再生效。

@Configuration
public class DateFormatConfig2 {@Value("${spring.jackson.date-format:yyyy-MM-dd HH:mm:ss}")private String pattern;public static DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");@Bean@Primarypublic ObjectMapper serializingObjectMapper() {ObjectMapper objectMapper = new ObjectMapper();JavaTimeModule javaTimeModule = new JavaTimeModule();javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer());javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer());objectMapper.registerModule(javaTimeModule);return objectMapper;}@Componentpublic class DateSerializer extends JsonSerializer<Date> {@Overridepublic void serialize(Date date, JsonGenerator gen, SerializerProvider provider) throws IOException {String formattedDate = dateFormat.format(date);gen.writeString(formattedDate);}}@Componentpublic class DateDeserializer extends JsonDeserializer<Date> {@Overridepublic Date deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {try {return dateFormat.parse(jsonParser.getValueAsString());} catch (ParseException e) {throw new RuntimeException("Could not parse date", e);}}}public class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {@Overridepublic void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers) throws IOException {gen.writeString(value.format(DateTimeFormatter.ofPattern(pattern)));}}public class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {@Overridepublic LocalDateTime deserialize(JsonParser p, DeserializationContext deserializationContext) throws IOException {return LocalDateTime.parse(p.getValueAsString(), DateTimeFormatter.ofPattern(pattern));}}
}

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