Java 弹簧数据不存在'；t log findById

创建了

客户

实体和存储库：

public interface CustomerRepository extends CrudRepository<Customer, Long> {
}

我没有在日志中看到

select

query，只有持久化实体的日志记录：

2019-12-28 16:29:56.732  INFO 17623 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2019-12-28 16:29:57.331  INFO 17623 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 4.526 seconds (JVM running for 5.198)
2019-12-28 16:29:57.382 DEBUG 17623 --- [           main] org.hibernate.SQL                        : insert into customer (first_name, last_name) values (?, ?)
customer Optional[Customer[id=73, firstName='Jack3', lastName='Bauer']]
2019-12-28 16:30:03.455  INFO 17623 --- [       Thread-2] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2019-12-28 16:30:03.457  INFO 17623 --- [       Thread-2] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2019-12-28 16:30:03.462  INFO 17623 --- [       Thread-2] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.

这是主要课程：

@SpringBootApplication
public class DemoApplication
{
  private static final Logger log = LoggerFactory.getLogger(DemoApplication.class);

  public static void main(String[] args)
  {
    SpringApplication.run(DemoApplication.class, args);
  }
  @Autowired
  BeanClass bc;
  @Bean
  public CommandLineRunner demo(CustomerRepository repository)
  {

    return (args) -> {
      bc.tran();
    };
  }
}

---

可以记录

findById

吗？

这是预期的：它不需要执行任何查询，因为您只是在同一事务中持久化了实体：它在一级缓存中

顺便说一句，当时它甚至还没有被插入到数据库中

---

如果执行一个事务以保存实体，另一个事务以按ID查找实体，那么您将看到正在执行SQL查询。

这是意料之中的：它不需要执行任何查询，因为您只是在同一事务中持久化实体：它在一级缓存中

顺便说一句，当时它甚至还没有被插入到数据库中

---

如果执行一个事务以保存实体，另一个事务以按ID查找实体，则会看到正在执行SQL查询。

原因一级hibernate缓存

---

未记录findById，因为它位于同一事务（在输入方法tran（）时启动）和同一Hibernate会话中。findById的select查询未执行，因为对象已在当前会话中加载。

原因是一级hibernate缓存

未记录findById，因为它位于同一事务（在输入方法tran（）时启动）和同一Hibernate会话中。findById的select查询未执行，因为对象已在当前会话中加载

2019-12-28 16:29:56.732  INFO 17623 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2019-12-28 16:29:57.331  INFO 17623 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 4.526 seconds (JVM running for 5.198)
2019-12-28 16:29:57.382 DEBUG 17623 --- [           main] org.hibernate.SQL                        : insert into customer (first_name, last_name) values (?, ?)
customer Optional[Customer[id=73, firstName='Jack3', lastName='Bauer']]
2019-12-28 16:30:03.455  INFO 17623 --- [       Thread-2] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2019-12-28 16:30:03.457  INFO 17623 --- [       Thread-2] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2019-12-28 16:30:03.462  INFO 17623 --- [       Thread-2] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.

@SpringBootApplication
public class DemoApplication
{
  private static final Logger log = LoggerFactory.getLogger(DemoApplication.class);

  public static void main(String[] args)
  {
    SpringApplication.run(DemoApplication.class, args);
  }
  @Autowired
  BeanClass bc;
  @Bean
  public CommandLineRunner demo(CustomerRepository repository)
  {

    return (args) -> {
      bc.tran();
    };
  }
}