Spring数据配置和Postgres数据库集成（没有xml配置）

Question

我有一个基于Spring框架的项目，它只基于Java配置进行初始化。这意味着不需要使用web.xml文件。

您可以在下面的图像中看到项目的结构：

• Java 7
• Spring framework 4.2.1.发布
• HibernateORM 5.0.4.final
• Spring Tool Suite IDE 3.6.2
• Maven3
• Tomcat 7

public class AppInitializer implements WebApplicationInitializer {

    private static final String CONFIG_LOCATION = "com.project.app.config";
    private static final String MAPPING_URL = "/";

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {

        // Create the 'root' Spring application context
        WebApplicationContext context = getContext();

        // Manage the lifecycle of the root application context
        servletContext.addListener(new ContextLoaderListener(context));

        // Register and map the dispatcher servlet
        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet",
                new DispatcherServlet(context));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping(MAPPING_URL);

    }

    private AnnotationConfigWebApplicationContext getContext() {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.setConfigLocation(CONFIG_LOCATION);

        return context;
    }

}

@EnableWebMvc
@Configuration
@ComponentScan(basePackages = { "com.project.app" })
public class WebMvcConfig extends WebMvcConfigurerAdapter {

    @Autowired
    private Environment env;

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/resources/**").addResourceLocations("/resources/");
    }

    @Override
    public void addViewControllers(ViewControllerRegistry registry) {
        registry.addViewController("/").setViewName("hello");
    }

    @Bean
    public ApplicationContextProvider applicationContextProvider() {
        return new ApplicationContextProvider();
    }
}

数据源

@Component
@PropertySource("classpath:application.properties")
public class DataSources {

    @Autowired
    private Environment env;

    @Bean
    @Primary
    public DataSource dataSource() {
        org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();

        String url = env.getProperty(SystemSettings.DS_URL);
        String user = env.getProperty(SystemSettings.DS_USERNAME);
        String pass = env.getProperty(SystemSettings.DS_PASSWORD);

        ds.setDriverClassName("org.postgresql.Driver");
        ds.setUrl(url);
        ds.setUsername(user);
        ds.setPassword(pass);

        return ds;
    }

}

而SystemSettings保存数据库的用户名、密码和url

@Service
@Configuration
public class SystemSettings implements Settings {  

    public static final String DS_URL = "datasource.app.url";
    public static final String DS_USERNAME = "datasource.app.username";
    public static final String DS_PASSWORD = "datasource.app.password";

    @Autowired
    private Environment env;

    @Override
    public String get(String key) {
        return env.getProperty(key);
    }

}

这些值是从Application.Properties文件中提取的，因为它在DataSources类中表示。

@Entity
@Table(name = "stop")
public class StopJPA {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Long id;

    @Column(name = "description")
    private String stopDescription;

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

    public StopJPA() {
    }

    public StopJPA(String stopDescription, String idStop) {
        this.stopDescription = stopDescription;
        this.idStop = idStop;
    }

    public Long getId() {
        return id;
    }

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

    public String getStopDescription() {
        return stopDescription;
    }

    public void setStopDescription(String stopDescription) {
        this.stopDescription = stopDescription;
    }

    public String getIdStop() {
        return idStop;
    }

    public void setIdStop(String idStop) {
        this.idStop = idStop;
    }

}

/**
 * Repository interface for StopJPA entities.
 */
@Repository
@RepositoryRestResource(collectionResourceRel = "stop", path = "stop")
public interface StopRepository extends CrudRepository<StopJPA, Long> {

    StopJPA findById(@Param("id") Long id);

}

在所有这些设置和配置之后，我设法使项目运行，但没有在数据库中创建表。

• 配置步骤中缺少什么？
• 如何让Spring扫描JPA实体并创建数据库？

我的主要目的是配置Spring（通过使用Spring Data JPA）和Hibernate，使它们在不使用xml配置文件和Spring Boot依赖项的情况下协同工作。后者意味着必须“手动”配置环境。

PersistenceContext

@Component
@EnableTransactionManagement
@PropertySource("classpath:application.properties")
public class PersistenceContext {

    @Autowired
    private Environment env;

    @Bean
    @Primary
    public DataSource dataSource() throws ClassNotFoundException {
        org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();

        String url = env.getProperty(SystemSettings.DS_URL);
        String user = env.getProperty(SystemSettings.USERNAME);
        String pass = env.getProperty(SystemSettings.DS_PASSWORD);

        ds.setDriverClassName("org.postgresql.Driver");
        ds.setUrl(url);
        ds.setUsername(user);
        ds.setPassword(pass);

        return ds;
    }

    @Bean
    LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(dataSource);
        entityManagerFactoryBean.setJpaVendorAdapter(new HibernateJpaVendorAdapter());
        entityManagerFactoryBean.setPackagesToScan("com.project.app.services.entities");

        Properties jpaProperties = new Properties();

        // Configures the used database dialect. This allows Hibernate to create SQL
        // that is optimized for the used database.
        jpaProperties.put("hibernate.dialect", env.getRequiredProperty("hibernate.dialect"));

        // Specifies the action that is invoked to the database when the Hibernate
        // SessionFactory is created or closed.
        jpaProperties.put("hibernate.hbm2ddl.auto",
                env.getRequiredProperty("hibernate.hbm2ddl.auto"));  

        // If the value of this property is true, Hibernate writes all SQL
        // statements to the console.
        jpaProperties.put("hibernate.show_sql", env.getRequiredProperty("hibernate.show_sql"));

        // If the value of this property is true, Hibernate will format the SQL
        // that is written to the console.
        jpaProperties.put("hibernate.format_sql", env.getRequiredProperty("hibernate.format_sql"));

        entityManagerFactoryBean.setJpaProperties(jpaProperties);

        return entityManagerFactoryBean;
    }

    /**
     * Because we are using JPA, we have to create a transaction manager bean that integrates the
     * JPA provider with the Spring transaction mechanism. We can do this by using the
     * JpaTransactionManager class as the transaction manager of our application.
     *
     * We can configure the transaction manager bean by following these steps:
     *
     * -> Create a new JpaTransactionManager object. -> Configure the entity manager factory whose
     * transactions are managed by the created JpaTransactionManager object.
     **/
    @Bean
    JpaTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactory);
        return transactionManager;
    }
}

Ans还更新了属性文件

hibernate.dicult=org.hibernate.dicult.PostgreSQL方言
hibernate.hbm2ddl.auto=create-drop hibernate.show_sql=false
hibernate.format_sql=true

我不知道为什么它会给我这个例外。maven依赖项在那里，驱动程序也在类路径中。.有什么帮助吗？

Answer 1

JPA没有指定DDL生成/迁移。默认情况下，Hibernate不执行DDL生成/迁移，但是如果正确配置persistence.xml，则可以执行此操作。