java 数据库配置类Java + JPA + mysql

Posted 2021-05-08

@Configuration
@EnableTransactionManagement
public class DatabaseConfig {

  /**
   * DataSource definition for database connection. Settings are read from
   * the application.properties file (using the env object).
   */
  @Bean
  public DataSource dataSource() {
    DriverManagerDataSource dataSource = new DriverManagerDataSource();
    dataSource.setDriverClassName(env.getProperty("db.driver"));
    dataSource.setUrl(env.getProperty("db.url"));
    dataSource.setUsername(env.getProperty("db.username"));
    dataSource.setPassword(env.getProperty("db.password"));
    return dataSource;
  }

  /**
   * Declare the JPA entity manager factory.
   */
  @Bean
  public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean entityManagerFactory =
        new LocalContainerEntityManagerFactoryBean();
    
    entityManagerFactory.setDataSource(dataSource);
    
    // Classpath scanning of @Component, @Service, etc annotated class
    entityManagerFactory.setPackagesToScan(
        env.getProperty("entitymanager.packagesToScan"));
    
    // Vendor adapter
    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    entityManagerFactory.setJpaVendorAdapter(vendorAdapter);
    
    // Hibernate properties
    Properties additionalProperties = new Properties();
    additionalProperties.put(
        "hibernate.dialect", 
        env.getProperty("hibernate.dialect"));
    additionalProperties.put(
        "hibernate.show_sql", 
        env.getProperty("hibernate.show_sql"));
    additionalProperties.put(
        "hibernate.hbm2ddl.auto", 
        env.getProperty("hibernate.hbm2ddl.auto"));
    entityManagerFactory.setJpaProperties(additionalProperties);
    
    return entityManagerFactory;
  }

  /**
   * Declare the transaction manager.
   */
  @Bean
  public JpaTransactionManager transactionManager() {
    JpaTransactionManager transactionManager = 
        new JpaTransactionManager();
    transactionManager.setEntityManagerFactory(
        entityManagerFactory.getObject());
    return transactionManager;
  }
  
  /**
   * PersistenceExceptionTranslationPostProcessor is a bean post processor
   * which adds an advisor to any bean annotated with Repository so that any
   * platform-specific exceptions are caught and then rethrown as one
   * Spring's unchecked data access exceptions (i.e. a subclass of 
   * DataAccessException).
   */
  @Bean
  public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
    return new PersistenceExceptionTranslationPostProcessor();
  }

  // Private fields
  
  @Autowired
  private Environment env;

  @Autowired
  private DataSource dataSource;

  @Autowired
  private LocalContainerEntityManagerFactoryBean entityManagerFactory;

}