错误内容：
Could not write JSON: write javaBean error, fastjson version 1.2.41, class org.springframework.data.domain.PageImpl, write javaBean error, fastjson version 1.2.41, class com.sun.proxy.$Proxy119, fieldName : 0; nested exception is com.alibaba.fastjson.JSONException: write javaBean error, fastjson version 1.2.41, class org.springframework.data.domain.PageImpl, write javaBean error, fastjson version 1.2.41, class com.sun.proxy.$Proxy119, fieldName : 0

下面是部分代码

public interface OperationPJ {
    String getId();
    String getState();
}

public interface OperationRepository extends CrudRepository<Operation,String> {
    Page<OperationPJ> findByCarInfoNo(String carInfoId, Pageable pageable);
}

@Service
public class OperationService {
    @Autowired
    private OperationRepository operationRepository;

    public Page<OperationPJ> findByCarInfoNo(String carInfoNo, Pageable pageable) {
        return operationRepository.findByCarInfoNo(carInfoNo, pageable);
    }
}

spring data jpa projections文档
https://docs.spring.io/spring-data/jpa/docs/2.0.2.RELEASE/reference/html/#projections