1. 问题描述

• springboot项目中，对于LocalDateTime 的序列化，前端展示结果为带“T”的日期，如下：

  2022-08-06T18:23:30
  1

  
• 而且在反序列化时，接收前端传来的 "updateTime": "2022-08-09 16:41:53"，这种格式的日期解析不了，要中间加个T才可以，就是这种的"2022-07-18T21:40:38"，为了项目统一化，一般我们不针字段一个个处理，不管前端还是后端，所以我们需要统一处理这种格式，解决问题请继续

2. 解决（统一处理）

• 两种方式：

• ① 写一个配置了即可，不多说了，直接给代码

  import com.fasterxml.jackson.databind.*;
  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 org.springframework.boot.autoconfigure.jackson.Jackson2ObjectMapperBuilderCustomizer;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  
  import java.time.LocalDate;
  import java.time.LocalDateTime;
  import java.time.LocalTime;
  import java.time.format.DateTimeFormatter;
  import java.util.HashMap;
  import java.util.Map;
  
  /**
   * description 统一处理返回前端的json格式
   * @author susu
   **/
  @Configuration
  public class LocalDateConfig {
  
      private static final DateTimeFormatter FORMAT_YMD_TIME = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
      private static final DateTimeFormatter FORMAT_YMD = DateTimeFormatter.ofPattern("yyyy-MM-dd");
      private static final DateTimeFormatter FORMAT_TIME = DateTimeFormatter.ofPattern("HH:mm:ss");
  
  
      @Bean
      public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() {
          Map<Class<?>, JsonSerializer<?>> serializers = new HashMap<>();
          serializers.put(LocalDateTime.class, new LocalDateTimeSerializer(FORMAT_YMD_TIME));
          serializers.put(LocalDate.class, new LocalDateSerializer(FORMAT_YMD));
          serializers.put(LocalTime.class, new LocalTimeSerializer(FORMAT_TIME));
  
          Map<Class<?>, JsonDeserializer<?>> deserializers = new HashMap<>();
          deserializers.put(LocalDateTime.class, new LocalDateTimeDeserializer(FORMAT_YMD_TIME));
          deserializers.put(LocalDate.class, new LocalDateDeserializer(FORMAT_YMD));
          deserializers.put(LocalTime.class, new LocalTimeDeserializer(FORMAT_TIME));
          return builder -> builder.serializersByType(serializers).deserializersByType(deserializers);
      }
  
  }
  
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• ② 还是一个配置类 MvcConfig.java

  @Configuration
  public class MvcConfig {
      /**
       * 更改jackson默认配置
       */
      @Bean
      public ObjectMapper ObjectMapper() {
          ObjectMapper objectMapper = new ObjectMapper();
          // 日期和时间格式化
          JavaTimeModule javaTimeModule = new JavaTimeModule();
          javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
          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(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
          javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
          objectMapper.registerModule(javaTimeModule);
          return objectMapper;
      }
   
  }
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  • 参考：
    Jackson在springboot中LocalDateTime格式问题

3. 单一处特殊处理

• 统一处理固然是好，但是不排除有特殊的需求，不能统一处理的，所以还得考虑如果不统一处理，又要满足自己的格式需求，改怎么实现？，看下面：

3.1 序列化

• 不贴了，只需把上面 MvcConfig.java 序列化的代码拿出来即可

3.2 反序列化

• 直接看代码吧

• ① 方式一：

  package com.liu.susu.common;
  
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.DeserializationContext;
  import com.fasterxml.jackson.databind.JsonDeserializer;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.commons.lang.StringUtils;
  
  import java.io.IOException;
  import java.time.LocalDateTime;
  import java.time.format.DateTimeFormatter;
  import java.time.format.FormatStyle;
  
  @Slf4j
  public class MyLocalDateTimeDeserialize extends JsonDeserializer<LocalDateTime> {
  
      private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofLocalizedDateTime(FormatStyle.MEDIUM);
  
      @Override
      public LocalDateTime deserialize(JsonParser p, DeserializationContext dc) throws IOException, JsonProcessingException {
  
          String str = p.getText();
          if (StringUtils.isNotEmpty(str)){
              return LocalDateTime.parse(str, MyLocalDateTimeDeserialize.DATE_FORMATTER);
          }
          
          return null;
  
      }
  
  }
  
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• ② 方式二：

  package com.liu.susu.common;
  
  import com.fasterxml.jackson.core.JsonParser;
  import com.fasterxml.jackson.core.JsonProcessingException;
  import com.fasterxml.jackson.databind.DeserializationContext;
  import com.fasterxml.jackson.databind.JsonDeserializer;
  import lombok.extern.slf4j.Slf4j;
  import org.apache.commons.lang.StringUtils;
  
  import java.io.IOException;
  import java.time.LocalDateTime;
  import java.time.format.DateTimeFormatter;
  
  @Slf4j
  public class MyLocalDateTimeDeserialize extends JsonDeserializer<LocalDateTime> {
      
      private static final String FORMAT_1 = "yyyy-MM-dd HH:mm:ss";
  
      @Override
      public LocalDateTime deserialize(JsonParser p, DeserializationContext dc) throws IOException, JsonProcessingException {
  
          String str = p.getText();
          if (StringUtils.isNotEmpty(str)){
              return LocalDateTime.parse(str,DateTimeFormatter.ofPattern(FORMAT_1));
          }
  
          return null;
  
      }
  
  }
  
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