Spring Boot SessionFactory 返回 NullPointer答案

【问题标题】：Spring Boot SessionFactory returning NullPointerSpring Boot SessionFactory 返回 NullPointer
【发布时间】：2017-10-14 17:58:10
【问题描述】：

我正在尝试将 SpringBoot 中的本机查询返回到 DTO。但是，我的 SessionFactory 正在返回 null。我在 SO 中阅读了很多问题，但似乎没有人提供帮助。

我在这里做错了什么？

application.properties

spring.jpa.properties.hibernate.current_session_context_class=org.springframework.orm.hibernate4.SpringSessionContext

SessionFactoryConfig.class

import org.hibernate.SessionFactory;
import org.hibernate.jpa.HibernateEntityManagerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class SessionFactoryConfig {

    @Bean
    public SessionFactory sessionFactory(HibernateEntityManagerFactory hemf) {
        return hemf.getSessionFactory();
    }
}

ReportAverageCost.class

import lombok.*;
import org.hibernate.SQLQuery;
import org.hibernate.SessionFactory;
import org.hibernate.transform.ResultTransformer;
import org.hibernate.transform.Transformers;
import org.springframework.beans.factory.annotation.Autowired;

import java.util.Date;
import java.util.List;

@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class ReportAverageCost {

    @Autowired
    private SessionFactory sessionFactory;

    public Date date;

    public List getReportAverageCost() throws Exception {
        String q = "SELECT (...)";

        SQLQuery query = sessionFactory.getCurrentSession().createSQLQuery(q);
        query.addScalar("date");
        ResultTransformer aliasToBean = Transformers.aliasToBean(ReportAverageCost.class);
        List result = query.setResultTransformer(aliasToBean).list();
        return result;
    }
}

【问题讨论】：

标签： java spring hibernate spring-boot

【解决方案1】：

在 ReportAverageCost 类上定义注释 @Component。

【讨论】：

感谢@Sagar，但它没有用。我找到了另一个解决方案并发布为答案

【解决方案2】：

这个网站帮助了我：https://blog.pranavek.com/using-hibernate-sessionfactory-in-spring-boot-app/

所以我的代码是这样的：

application.properties

spring.jpa.properties.hibernate.current_session_context_class=thread

ReportAverageCostRepository.class

@Repository
public class ReportAverageCostRepository {

    @Autowired
    private SessionFactory sessionFactory;

    public List getReportAverageCost() throws Exception {
        String q = "SELECT (...)";

        Session session = this.sessionFactory.getCurrentSession();
        session.beginTransaction();

        SQLQuery query = session.createSQLQuery(q);
        query.addScalar("date");
        query.addScalar("transactionIdentifier");
        query.addScalar("amount");
        query.addScalar("cost");
        query.addScalar("price");

        ResultTransformer aliasToBean = Transformers.aliasToBean(ReportAverageCost.class);
        List result = query.setResultTransformer(aliasToBean).list();

        session.getTransaction().commit();

        return result;
    }

}

ReportAverageCostController.class

@RestController
@RequestMapping(value = "/api/v1/reports/averageCost")
public class ReportAverageCostController {

    @Autowired
    ReportAverageCostRepository reportAverageCostRepository;

    @RequestMapping(value = "/{pair}", method = RequestMethod.GET)
    public List<ReportAverageCost> reportAverageCost() throws Exception {
        return reportAverageCostRepository.getReportAverageCost();
    }
}

【讨论】：