使用 Spring Data JPA、Hibernate 和 PostgreSQL 从数据库打印一行

Question

I would like to simply print a row from a database created automatically using Spring Boot JPA and Hibernate. I am missing something on how to do it and did not find it online. The reason why I am trying is mostly for testing if the connection to the database is working and also that the function to retrieve data are working.

I am trying to print a row using the main function, but the problem is that @Autowired in the main function does not work as I would like because it's static.

The class where the Forum object is defined.

@Entity
@Table(name = "forum")
public class Forum {
    @Id
    private long id;

    @Column(name = "title")
    private  String title;

    @Column(name = "creationDate")
    @Temporal(TemporalType.TIMESTAMP)
    private Date creationDate;
    //GETTER AND SETTER
} 

//The interface where I define some data retrieval functions.

@Repository
public interface ForumRepository extends CrudRepository<Forum, Long> {
    List<Forum> findAll();
    Forum findById(long id);
}


@Service
public class Test {
    @Autowired
    ForumRepository repo;

    public Forum test(){
        return repo.findById(760);
    }
}

Answer 1

The simplest way is to dump the queries to standard out is to add the following to application.properties:

spring.jpa.show-sql=true

To beautify or pretty print the SQL, we can add:

spring.jpa.properties.hibernate.format_sql=true

To also print parameters use logging instead:

logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE

Reference link: https://www.baeldung.com/sql-logging-spring-boot

Answer 2

Execute the following as Junit test:

@SpringBootTest
@RunWith(SpringRunner.class)
public class Test {

    @Autowired
    ForumRepository repo;

    @Test
    public voidtest(){
        assertEquals(repo.findById(720).getId(), 720);
    }
}

Answer 3

Just put @PostConstruct on your Test::test method if you want a really quick check. Otherwise, as already mentioned, tests are the way to go.