方法有這三種
- 使用hibernate.cfg.xml文件建立Hibernate SessionFactory
- 使用Java HashMap和ServiceRegistry class在Hibernate中建立SessionFactory
- 從JPA的EntityManager中獲得Hibernate SessionFactory
1. 使用hibernate.cfg.xml文件建立Hibernate SessionFactory
這是官方建議的方法，hibernate.cfg.xml內容如下:
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| <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
<!-- property name="connection.driver_class">com.mysql.jdbc.Driver</property -->
<property name="connection.url">jdbc:mysql://localhost/hibernate_examples</property>
<property name="connection.username">root</property>
<property name="connection.password">password</property>
<property name="connection.pool_size">3</property>
<property name="dialect">org.hibernate.dialect.MySQL8Dialect</property>
<property name="current_session_context_class">thread</property>
<property name="show_sql">true</property>
<property name="format_sql">true</property>
<property name="hbm2ddl.auto">update</property>
<!-- mapping class="com.mcnz.jpa.examples.Player" / -->
</session-factory>
</hibernate-configuration>
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接著在就可以在Java內去建立Hibernate SessionFactory:
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| public static Session getCurrentSessionFromConfig() {
// SessionFactory in Hibernate 5 example
Configuration config = new Configuration();
config.configure();
// local SessionFactory bean created
SessionFactory sessionFactory = config.buildSessionFactory();
Session session = sessionFactory.getCurrentSession();
return session;
}
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2. 使用Java HashMap和ServiceRegistry class在Hibernate中建立SessionFactory
個人覺得用xml檔來儲存像是資料庫位址與帳密實在是太危險，好在能夠使用一個HashMap來把資料儲存起來傳送給ServiceRegistry，這樣就不需要去建立hibernate.cfg.xml了
更正:將資料庫與帳密等變數資訊加密後放置在主機的環境變數會是較好的做法
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| public static Session getCurrentSession() {
// Hibernate 5.4 SessionFactory example without XML
Map<String, String> settings = new HashMap<>();
settings.put("connection.driver_class", "com.mysql.jdbc.Driver");
settings.put("dialect", "org.hibernate.dialect.MySQL8Dialect");
settings.put("hibernate.connection.url",
"jdbc:mysql://localhost/hibernate_examples");
settings.put("hibernate.connection.username", "root");
settings.put("hibernate.connection.password", "password");
settings.put("hibernate.current_session_context_class", "thread");
settings.put("hibernate.show_sql", "true");
settings.put("hibernate.format_sql", "true");
ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
.applySettings(settings).build();
MetadataSources metadataSources = new MetadataSources(serviceRegistry);
// metadataSources.addAnnotatedClass(Player.class);
Metadata metadata = metadataSources.buildMetadata();
// here we build the SessionFactory (Hibernate 5.4)
SessionFactory sessionFactory = metadata.getSessionFactoryBuilder().build();
Session session = sessionFactory.getCurrentSession();
return session;
}
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3. 從JPA的EntityManager中獲得Hibernate SessionFactory
直接使用JPA去取得 hibernate session內的資料
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| public static SessionFactory getCurrentSessionFromJPA() {
// JPA and Hibernate SessionFactory example
EntityManagerFactory emf =
Persistence.createEntityManagerFactory("jpa-tutorial");
EntityManager entityManager = emf.createEntityManager();
// Get the Hibernate Session from the EntityManager in JPA
Session session = entityManager.unwrap(org.hibernate.Session.class);
SessionFactory factory = session.getSessionFactory();
return factory;
}
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References
Build a Hibernate SessionFactory by example