請求的json報文中可能會出現 一下幾種：

['2019-01-01','2019-01-01 12:03:34','20190101120334']

但是接收的Request實體類日期欄位是LocalDateTime型別 

LocalDateTime applyDate;

希望的情況是 ：

1. 輸入 yyyy-MM-dd HH:mm:ss 、yyyyMMddHHmmss等精確到秒的格式，可以自動被封裝LocalDateTime；
2. 輸入 yyyy-MM-dd 、yyyyMMdd等精確到日的格式，也可以被封裝成LocalDateTime,  HHmmss預設為000000；

預設情況下，是沒辦法 自動轉換的，需要在 ObjectMapper中配置，網上主流的配置如下

@Configuration
@Slf4j
public class MvcConfig implements WebMvcConfigurer {

    /**
     * 更改jackson預設配置
     * @return
     */
    @Bean
    @Primary
    public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder){
        //日期和時間格式化
        JavaTimeModule javaTimeModule = new JavaTimeModule();
        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyyMMddHHmmss")));
        javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));

        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyyMMddHHmmss")));
        javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalDateTime.class,new MyLocalDateTimeDeserializer());
        objectMapper.registerModule(javaTimeModule);
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        return objectMapper;
    }
}
 

但實際效果是，上面第二種情況沒法生效。百度了很多也都是重複內容，無效。google得一答案：

@Configuration
@Slf4j
public class MvcConfig implements WebMvcConfigurer {

    /**
     * 更改jackson預設配置
     * @return
     */
    @Bean
    @Primary
    public ObjectMapper objectMapper(Jackson2ObjectMapperBuilder builder){
        ObjectMapper objectMapper = builder.json().build();

        SimpleModule simpleModule = new SimpleModule();
        simpleModule.addDeserializer(LocalDateTime.class,new MyLocalDateTimeDeserializer());
        objectMapper.registerModule(simpleModule);

        //忽視請求報文中未匹配到的欄位（多餘的欄位）
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        return objectMapper;
    }
}
 

需要自定義反序列化類

MyLocalDateTimeDeserializer

public class MyLocalDateTimeDeserializer  extends JsonDeserializer<LocalDateTime> {


    @Override
    public LocalDateTime deserialize(JsonParser parser, DeserializationContext context) throws IOException {
        String dateStr = parser.getText();
        DateTime dateTime = null;
        try{
            dateTime = DateUtil.parse(dateStr);
        }catch (Exception e){
            dateTime = DateUtil.parseDateTime(dateStr.replaceAll("T"," "));
        }
        Date date = dateTime.toJdkDate();
        Instant instant = date.toInstant();
        ZoneId zoneId = ZoneId.systemDefault();
        LocalDateTime localDateTime = instant.atZone(zoneId).toLocalDateTime();
        return localDateTime;
    }

    @Override
    public Class<?> handledType() {
        return LocalDateTime.class;
    }
}

deserialize方法的邏輯就靠自己實現了，我這邊是藉助了hutool工具類進行了簡化。

沒啥技術含量，就是一個坑