有的人说单独写一个localDateTime配置类，看了一下可以不用。
直接写WebMvcConfig里面就行

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.module.SimpleModule;
import com.fasterxml.jackson.databind.ser.std.ToStringSerializer;
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 lombok.AllArgsConstructor;
import org.springframework.context.annotation.Configuration;
import org.springframework.format.FormatterRegistry;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import java.math.BigInteger;
import java.nio.charset.Charset;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.format.DateTimeFormatter;@EnableWebMvc
@Configuration
@AllArgsConstructor
public class WebMvcConfig implements WebMvcConfigurer {protected static final String DEFAULT_DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";protected static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";protected static final String DEFAULT_TIME_FORMAT = "HH:mm:ss";/*** 处理 Long 类型在 Jackson 中丢失精度* 如果使用 FastJson 可以修改这里对实现* @param converters 消息转换器*/@Overridepublic void configureMessageConverters(List<HttpMessageConverter<?>> converters) {MappingJackson2HttpMessageConverter jackson2HttpMessageConverter =new MappingJackson2HttpMessageConverter();ObjectMapper objectMapper = new ObjectMapper();SimpleModule simpleModule = new SimpleModule();simpleModule.addSerializer(BigInteger.class, ToStringSerializer.instance).addSerializer(Long.class, ToStringSerializer.instance).addSerializer(Long.TYPE, ToStringSerializer.instance)//加上就能将前端json中String类型时间解析为LocalDateTime类型.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT))).addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT))).addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT))).addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_TIME_FORMAT))).addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern(DEFAULT_DATE_FORMAT))).addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern(DEFAULT_TIME_FORMAT)));;objectMapper.registerModule(simpleModule);jackson2HttpMessageConverter.setObjectMapper(objectMapper);converters.add(jackson2HttpMessageConverter);converters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));}}