Spring+Redis项目序列化java.time.Instant报错求助

问题复现步骤 #

• 项目搭建
  1. 使用IntelliJ IDEA 2023.1.4旗舰版创建Spring Initializr项目
  2. 选择Java语言、Gradle-Kotlin构建方式，Spring Boot版本为3.1.4
  3. 添加依赖：Lombok、Spring Web、Spring Data Redis（Access+Driver）
• 应用配置：在src/main/resources/application.properties中添加Redis连接信息

  spring.data.redis.host=localhost
  spring.data.redis.port=6379
  

  （本地Redis容器运行正常，已验证6379端口可访问）
• 自定义数据类MyObject

  package com.example.demo;
  
  import lombok.Data;
  import java.time.Instant;
  
  @Data
  public class MyObject {
      Instant timestamp;
      String textPayload;
  }
  

• 配置类AppConfig

  package com.example.demo;
  
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.data.redis.connection.RedisConnectionFactory;
  import org.springframework.data.redis.core.RedisTemplate;
  import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
  import org.springframework.data.redis.serializer.StringRedisSerializer;
  
  @Configuration
  public class AppConfig {
      @Bean
      public RedisTemplate<String, MyObject> redisTemplate(RedisConnectionFactory factory) {
          RedisTemplate<String, MyObject> template = new RedisTemplate<>();
          template.setConnectionFactory(factory);
          template.setKeySerializer(new StringRedisSerializer());
          template.setValueSerializer(new GenericJackson2JsonRedisSerializer());
          return template;
      }
  }
  

• 控制器MyController

  package com.example.demo;
  
  import lombok.AccessLevel;
  import lombok.RequiredArgsConstructor;
  import lombok.experimental.FieldDefaults;
  import org.springframework.data.redis.core.RedisTemplate;
  import org.springframework.http.ResponseEntity;
  import org.springframework.web.bind.annotation.GetMapping;
  import org.springframework.web.bind.annotation.RestController;
  import java.time.Instant;
  
  @FieldDefaults(makeFinal = true, level = AccessLevel.PRIVATE)
  @RequiredArgsConstructor
  @RestController
  public class MyController {
      RedisTemplate<String, MyObject> redisTemplate;
  
      @GetMapping("/save")
      public ResponseEntity<String> saveObject() {
          MyObject myObject = new MyObject();
          myObject.setTimestamp(Instant.now());
          myObject.setTextPayload("some data");
          redisTemplate.opsForValue().set("myObject", myObject);
          return ResponseEntity.ok("Object saved");
      }
  
      @GetMapping("/read")
      public ResponseEntity<MyObject> readObject() {
          return ResponseEntity.ok(redisTemplate.opsForValue().get("myObject"));
      }
  }
  

异常信息 #

调用/save接口时抛出以下异常：

com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Java 8 date/time type `java.time.Instant` not supported by default: add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling (through reference chain: com.example.demo.MyObject["timestamp"])
    ...（省略堆栈信息）

已尝试的无效方案 #

• 添加jackson-datatype-jsr310依赖到build.gradle.kts

  implementation("com.fasterxml.jackson.datatype:jackson-datatype-jsr310")
  

• 在配置类中注册ObjectMapper Bean（两种写法）

  @Bean
  public ObjectMapper objectMapper() {
      ObjectMapper objectMapper = new ObjectMapper();
      objectMapper.registerModule(new JavaTimeModule());
      return objectMapper;
  }
  

  @Bean
  public ObjectMapper objectMapper() {
      return JsonMapper.builder()
                       .addModule(new JavaTimeModule())
                       .build();
  }
  

• 注册Jackson2ObjectMapperBuilder Bean

  @Bean
  public Jackson2ObjectMapperBuilder jackson2ObjectMapperBuilder() {
      return new Jackson2ObjectMapperBuilder().modules(new JavaTimeModule());
  }
  

正确解决方案 #

问题核心在于GenericJackson2JsonRedisSerializer默认会自行创建独立的ObjectMapper实例，不会自动复用Spring容器中配置好的ObjectMapper。需要手动创建注册了JavaTimeModule的ObjectMapper，并传递给GenericJackson2JsonRedisSerializer。

修改AppConfig中的redisTemplate Bean：

@Configuration
public class AppConfig {
    @Bean
    public RedisTemplate<String, MyObject> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, MyObject> template = new RedisTemplate<>();
        template.setConnectionFactory(factory);
        template.setKeySerializer(new StringRedisSerializer());

        // 手动配置ObjectMapper并注册JavaTimeModule
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.registerModule(new JavaTimeModule());
        // 可选：关闭日期时间的时间戳序列化，转为ISO格式字符串
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        
        template.setValueSerializer(new GenericJackson2JsonRedisSerializer(objectMapper));
        return template;
    }
}

另外，Spring Boot 3.x中jackson-datatype-jsr310已被包含在spring-boot-starter-json依赖中（Spring Web会间接引入），因此无需额外添加该依赖，之前添加的可以移除。

内容的提问来源于stack exchange，提问作者overwriter