SpringMvc Json LocalDateTime 互转,form urlencoded @ModelAttribute 转换

JDK8 的LocalDate 系列日期API ,比Date 或者 Calendar 都好用很多,但是在SpringMvc 自动装配会有点小问题

会导致抛出类似异常

default message [Failed to convert property value of type 'java.lang.String' to required type 'java.time.LocalDateTime' for property 'createDate';
 nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type ... for value '2017-11-03';
 nested exception is java.lang.IllegalArgumentException: Parse attempt failed for value 

解决方法 1  注意 @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") form 或者url 传过来的 日期必须严格根据此 格式,实在没有的,需要在前端补全格式,否则依然会抛出以上异常

    @JsonDeserialize(using = LocalDateTimeDeserializer.class)  //application/json
    @JsonSerialize(using = LocalDateTimeSerializer.class) //application/json
　　//LocalDateTime
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")　　　　//application/x-www-form-urlencoded
    private LocalDateTime createDate;
　　//LocalDate

    @DateTimeFormat(pattern = "yyyy-MM-dd")　　　　//application/x-www-form-urlencoded
    private LocalDate createDate;

解决方法 2 此方法只处理json  不能处理 application/x-www-form-urlencoded 也就是说 @ModelAttribute 的时候还是需要  @DateTimeFormat 注解

继承 WebMvcConfigurerAdapter

  private static class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {

        private static final DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");

        @Override
        public void serialize(LocalDateTime value, JsonGenerator jgen, SerializerProvider provider)
                throws IOException {
            jgen.writeString(dateTimeFormatter.format(value));
        }

    }

    private static class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {

        @Override
        public LocalDateTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException {
            String result = StringDeserializer.instance.deserialize(jsonParser, deserializationContext);
            return LocalDateTimeUtil.UDateToLocalDateTime(DateUtil.parseDate(DateUtil.C_TIME_PATTON_DEFAULT,result));
        }
    }

   @Override
    public void extendMessageConverters(List<HttpMessageConverter<?>> converters) {
        for (HttpMessageConverter converter : converters) {
            if (converter instanceof MappingJackson2HttpMessageConverter) {
                ObjectMapper objectMapper = ((MappingJackson2HttpMessageConverter) converter).getObjectMapper();
                SimpleModule module = new SimpleModule();
                module.addSerializer(LocalDateTime.class,new LocalDateTimeSerializer());
                module.addDeserializer(LocalDateTime.class,new LocalDateTimeDeserializer());
                objectMapper.registerModule(module);
            }
        }
    }

 2018年3月12日 15:09:28 对 解决方法 2 的补充 在继承WebMvcConfigurerAdapter的配置类中注册转换器 可以支持application/x-www-form-urlencoded 的自动装配

 @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(new DateConverter());
        registry.addConverter(new LocalDateConverter());
        registry.addConverter(new LocalDateTimeConverter());
    }

    public static class DateConverter implements Converter<String, Date> {
        @Override
        public Date convert(String source) {
            if (!NumberUtils.isDigits(source))
                return null;
            Long milli = NumberUtils.createLong(source);
            return new Date(milli);
        }
    }

    public static class LocalDateTimeConverter implements Converter<String, LocalDateTime> {
        @Override
        public LocalDateTime convert(String source) {
            if (!NumberUtils.isDigits(source))
                return null;
            Long milli = NumberUtils.createLong(source);
            return LocalDateTime.ofEpochSecond(milli, 0, ZoneOffset.UTC);
        }
    }

    public static class LocalDateConverter implements Converter<String, LocalDate> {
        @Override
        public LocalDate convert(String source) {
            if (!NumberUtils.isDigits(source))
                return null;
            Long milli = NumberUtils.createLong(source);
            return LocalDateTime.ofEpochSecond(milli, 0, ZoneOffset.UTC).toLocalDate();
        }
    }