[FIXED] Spring boot + hibernate - entity is not mapped + best way to configuration

Issue

I'm trying to learn spring-boot basic annotation configuration with hibernate, to make myself a template that will always work.

I'm using spring-boot latest release version 1.51 on STS (spring tool suite) 3.8.3.

Here is my main:

@SpringBootApplication
@EnableAutoConfiguration
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

Now, I know that @SpringBootApplication automatically comes with @componetScan, so I didn't add it.

My configuration class:

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(entityManagerFactoryRef = "someEntityManagerFactory", transactionManagerRef = "someTransactionManager", basePackages = {
        "com.example.*" })
@EntityScan(basePackages = "com.demo.models")
@ConfigurationProperties(prefix = "mysql.datasource")
public class DataBaseConfig {

    @Autowired
    private Environment env;

    @Bean
    public DataSource someDataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName(env.getProperty("mysql.datasource.driver-class-name"));
        dataSource.setUrl(env.getProperty("mysql.datasource.url"));
        dataSource.setUsername(env.getProperty("mysql.datasource.username"));
        dataSource.setPassword(env.getProperty("mysql.datasource.password"));
        return dataSource;
    }

    @Bean
    public LocalContainerEntityManagerFactoryBean someEntityManagerFactory() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(someDataSource());
        em.setPackagesToScan(new String[] { "org.openlegacy.analytics.models" });
        JpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaProperties(additionalProperties());

        return em;
    }

    @Bean
    public PlatformTransactionManager someTransactionManager() {
        JpaTransactionManager tm = new JpaTransactionManager();
        tm.setEntityManagerFactory(someEntityManagerFactory().getObject());
        tm.setDataSource(someDataSource());
        return tm;
    }

    Properties additionalProperties() {
        Properties properties = new Properties();
        properties.setProperty("hibernate.hbm2ddl.auto", env.getProperty("spring.jpa.hibernate.ddl-auto"));
        properties.setProperty("hibernate.dialect", env.getProperty("spring.jpa.properties.hibernate.dialect"));
        properties.setProperty("spring.jpa.show-sql", env.getProperty("spring.jpa.show-sql"));
        properties.setProperty("spring.jpa.hibernate.naming.physical-strategy",
                env.getProperty("spring.jpa.hibernate.naming.physical-strategy"));
        return properties;
    }

}

My controller class:

@RestController
@RequestMapping("/users")
public class UserController {

    @Autowired
    private UserRepository userRipository;

    @RequestMapping(value = "", method = RequestMethod.GET)
    public List<User> getItems() {
        return userRipository.getUsers();
    }

    @RequestMapping(value = "/message", method = RequestMethod.GET)
    public String getMessage() {
        return userRipository.getMessage();
    }

}

My repository class:

@Transactional
@Repository
public class UserRepository {

    @PersistenceContext
    private EntityManager entityManager;

    @SuppressWarnings("unchecked")
    public List<User> getUsers() {
        return entityManager.createQuery("select u from User u").getResultList();
    }

    public String getMessage() {
        return "hello";
    }
}

My entity class:

@Entity(name = "user")
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Integer id;

    @Column(name = "user_name")
    private String userName;

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

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

and my properties file:

# DataSource settings: set here your own configurations for the database connection.
mysql.datasource.username=openlegacy
mysql.datasource.password=openlegacy
mysql.datasource.driver-class-name=com.mysql.jdbc.Driver
mysql.datasource.url=jdbc:mysql://localhost:3306/olbank
spring.jpa.database= MYSQL

spring.data.jpa.repositories.enabled=true
#spring.jpa.database-platform=org.hibernate.dialect.MYSQL5Dialect

# Show or not log for each sql query
spring.jpa.show-sql = true

# Hibernate ddl auto (create, create-drop, update)
spring.jpa.hibernate.ddl-auto = update

# Naming strategy
#spring.jpa.hibernate.naming.strategy= org.hibernate.cfg.ImprovedNamingStrategy
spring.jpa.hibernate.naming.physical-strategy= org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

# The SQL dialect makes Hibernate generate better SQL for the chosen database
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5Dialect

and when I'm tying to retrieve data from the user table, I get this error:

org.hibernate.hql.internal.ast.QuerySyntaxException: User is not mapped...

My questions are:

1. why am I getting this error? I know that user is mapped by the class name, and that's what I'm doing

2. is this the best way to configure hibernate with spring-boot? It's important for me to write code by the best practices.

Please give a detailed answer so I can learn from it.

Any other information that can be useful is welcome :)

Thanks.

Solution

Ok. You have a few things that need to be addressed in your overall configuration. You currently are providing an alias to your Entity User

@Entity(name = "user")

That is fine but if you are going to provide a name to your Entity then that is how you need to reference it in JPQL so, "select u from User u" would need to become

select u from user u

I might just suggest getting rid of your name qualifier and leave your query as "select u from User u".

Then secondly you do have some issues with package references:

1. In your @EnableJpaRepositories annotation change your basePackages to reference the base of your actual repository package, guessing "com.demo.repository". Get rid of the wildcard reference.

2. In your someEntityManagerFactory() method you are setting the basePackage to (something I imagine is incorrect) "org.openlegacy.analytics.models". You indicated your entity(s) is under "com.demo.models". So you should change that setter to

   em.setPackagesToScan(new String[] { "com.demo.models" });
   

That should do the trick.

Answered By - M. Rizzo
Answer Checked By - David Goodson (JavaFixing Volunteer)