org.springframework.data.domain.PageImpl 无法反序列化，当我想使用带有注释 @Cacheable(spring cache) 的 findAll(Pageable pageable) 时？

Question

As the title says,

@CacheConfig(cacheNames = {"familyUserDao"})
public interface FamilyUserDao extends JpaRepository<FamilyUser,Long> {
    @Override
    @Cacheable(key = "methodName +#p0")
    Page<FamilyUser> findAll(Pageable pageable);
}

But when I use this method like below :

Page<FamilyUser> familyUserPage = familyUserDao.findAll(pageable);

Error message:

org.springframework.data.redis.serializer.SerializationException: Could not read JSON: Can not construct instance of org.springframework.data.domain.PageImpl: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: [B@7fae8571; line: 1, column: 46]; nested exception is com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of org.springframework.data.domain.PageImpl: no suitable constructor found, can not deserialize from Object value (missing default constructor or creator, or perhaps need to add/enable type information?)
 at [Source: [B@7fae8571; line: 1, column: 46]
    at org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer.deserialize(Jackson2JsonRedisSerializer.java:73),

Is there any good advice provided? Any advice will be appreciated. Thank you very much!

Answer 1

The Jackson module requires you to provide a class object for deserialization that matches the structure of your JSON file. The parsing errors are almost always related with either:

• missing or unreachable class properties
• missing or default constructor

I believe in your case you are most probably missing a constructor that is suitable to deserialize this JSON. (guessing as you have not provided the source code for the PageImpl class)

You should be able to solve this error by either using lombok 's @AllArgsConstructor or by adding a new constructor which parameters match the fields in the JSON in question inside the PageImpl class.

Answer 2

DTO pojo class must should implements serialiazable

public class FamilyUserDTO  implements Serializable {         
    //members         
    // setters and getters 
}