背景

1. Java序列化工具用的是jackson
2. 序列化实体类的时候有LocalDateTime属性

最开始发现问题是因为用jackson的时候json字符串转实体类报错，报错内容：

JSON parse error: Cannot deserialize value of type java.time.LocalDateTime from String "2022-06-16 18:32:41": Failed to deserialize java.time.LocalDateTime: (java.time.format.DateTimeParseException) Text '2022-06-16 18:32:41' could not be parsed at index 10; nested exception is com.fasterxml.jackson.databind.exc.InvalidFormatException: Cannot deserialize value of type java.time.LocalDateTime from String "2022-06-16 18:32:41": Failed to deserialize java.time.LocalDateTime: (java.time.format.DateTimeParseException) Text '2022-06-16 18:32:41' could not be parsed at index 10\n at [Source: (PushbackInputStream); line: 3, column: 16]

原因是因为大家通常时间序列化成字符串的时候都是yyyy-MM-dd HH:mm:ss但是jackson默认的是国际化的时间标准

yyyy-MM-ddTHH:mm:ss区别就自安于中间多了个T，所以我们需要重写一个jackson的序列化工具

处理办法

springboot有个版本加入了jackson-datatype-jsr310这个依赖，我的是2.5.1，如果没有的话可以手动引一下

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.12.3</version>
</dependency>

然后写一个方法来覆盖原有的Bean，这样就行了

@Component
public class LocalDateTimeSerializerConfig {

    @Bean
    public ObjectMapper serializingObjectMapper() {
        JavaTimeModule module = new JavaTimeModule();
        LocalDateTimeDeserializer dateTimeDeserializer = new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        LocalDateTimeSerializer dateTimeSerializer = new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss"));
        module.addDeserializer(LocalDateTime.class, dateTimeDeserializer);
        module.addSerializer(LocalDateTime.class, dateTimeSerializer);
        return Jackson2ObjectMapperBuilder.json().modules(module)
                .featuresToDisable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS).build();
    }

}