一、问题

当我准备在boot程序启动时对业务对象进行初始化存储在redis中我发现服务启动报错为：Could not write JSON: Java 8 date/time type java.time.LocalDateTime not supported by default: add Module “com.fasterxml.jackson.datatype:jackson-datatype-jsr310” to enable handling
当时盲猜：业务对象LocalDateTime类型的属性在序列化报错

二、实际原因

Jackson库在默认情况下不支持Java8的LocalDateTime类型的序列化和反序列化。

三、解决方法

1.添加jackson依赖

  <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
            <version>2.12.5</version>
        </dependency>

2.修改RedisConfig

@Configuration
public class RedisConfig {
    @Bean
    public RedisSerializer<Object> redisSerializer() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        // 必须设置，否则无法将JSON转化为对象，会转化成Map类型
        objectMapper.activateDefaultTyping(LaissezFaireSubTypeValidator.instance, ObjectMapper.DefaultTyping.NON_FINAL);

        // 自定义ObjectMapper的时间处理模块
        JavaTimeModule javaTimeModule = new JavaTimeModule();

        javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")));

        javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));
        javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DateTimeFormatter.ofPattern("yyyy-MM-dd")));

        javaTimeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(DateTimeFormatter.ofPattern("HH:mm:ss")));
        javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DateTimeFormatter.ofPattern("HH:mm:ss")));

        objectMapper.registerModule(javaTimeModule);

        // 禁用将日期序列化为时间戳的行为
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);

        //创建JSON序列化器
        return new Jackson2JsonRedisSerializer<>(objectMapper, Object.class);
    }
    /**
     * 自定义 RedisTemplate
     * <p>
     * 修改 Redis 序列化方式，默认 JdkSerializationRedisSerializer
     *
     * @param redisConnectionFactory {@link RedisConnectionFactory}
     * @return {@link RedisTemplate}
     */
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);

        // 使用 String 序列化 key
        redisTemplate.setKeySerializer(RedisSerializer.string());
        redisTemplate.setHashKeySerializer(RedisSerializer.string());

        // 使用自定义的 JSON 序列化器（支持 LocalDateTime）
        redisTemplate.setValueSerializer(redisSerializer());
        redisTemplate.setHashValueSerializer(redisSerializer());

        redisTemplate.afterPropertiesSet();
        return redisTemplate;
    }
}

四、效果