java - Hibernate将sql保存到文件

Question

我想将实体序列化为 SQL 查询字符串并将其保存到 .txt 文件中，以便稍后能够将其写入数据库。我需要该解决方案无论使用哪种 SQL 方言都能工作，因此我想使用 Hibernate。

可以用 Hibernate 来实现吗？您能给我一个线索或教程吗？我怎样才能做到这一点？

假设我们有一个实体:

@Entity  
public class Project {
       @Id
       @GeneratedValue(strategy = GenerationType.SEQUENCE)
       private Long id;
       private String name;

       //... setters, getters and constructor
}

我想将一些实体序列化为 SQL 语句字符串，如下所示:

INSERT INTO project (name)
VALUES ('SQL Convertion Project');
INSERT INTO project (name)
VALUES ('DB Migration');
INSERT INTO project (name)
VALUES ('Stackoverflow is cool');

Answer 1

我找到了解决方案。我希望它会对某人有所帮助。

下面的代码使用 Hibernate 实体持久器获取实体项目的插入和更新查询。如果需要，我可以注入(inject)查询参数并将查询写入文件。

1. 仅使用 Hibernate 框架:

Configuration configuration = new Configuration().configure();
StandardServiceRegistryBuilder builder = new StandardServiceRegistryBuilder().
        applySettings(configuration.getProperties());
SessionFactory sessionFactory = configuration.buildSessionFactory(builder.build());

ClassMetadata hibernateMetadata = sessionFactory.getClassMetadata("com.mypackage.Project ");
if (hibernateMetadata == null){
    return;
}

if (hibernateMetadata instanceof AbstractEntityPersister) {
    AbstractEntityPersister persister = (AbstractEntityPersister) hibernateMetadata;

    for (Method method : persister.getClass().getSuperclass().getDeclaredMethods()) {
        if (method.getName().equalsIgnoreCase("getSQLInsertStrings")) {
            ReflectionUtils.makeAccessible(method);
            Object insertQueries = ReflectionUtils.invokeMethod(method, persister);

            for (String queryText : (String []) insertQueries) {
                System.out.println(queryText);
            }
        }

        if (method.getName().equalsIgnoreCase("getSQLUpdateStrings")) {
            ReflectionUtils.makeAccessible(method);
            Object insertQueries = ReflectionUtils.invokeMethod(method, persister);

            for (String queryText : (String []) insertQueries) {
                System.out.println(queryText);
            }
        }
    }
}

使用 Hibernate + Spring

ApplicationContext ctx = new ClassPathXmlApplicationContext( "ApplicationContext.xml");

EntityManager em = ((EntityManagerFactory) ctx.getBean("entityManagerFactory")).createEntityManager();
try {
    Session session = em.unwrap(Session.class);

    ClassMetadata hibernateMetadata = session.getSessionFactory().getClassMetadata("com.mypackage.Project");
    if (hibernateMetadata == null){
        return;
    }
    if (hibernateMetadata instanceof AbstractEntityPersister) {
        AbstractEntityPersister persister = (AbstractEntityPersister) hibernateMetadata;

        for (Method method : persister.getClass().getSuperclass().getDeclaredMethods()) {
            if (method.getName().equalsIgnoreCase("getSQLInsertStrings")) {
                ReflectionUtils.makeAccessible(method);
                Object insertQueries = ReflectionUtils.invokeMethod(method, persister);

                for (String queryText : (String []) insertQueries) {
                    System.out.println(queryText);
                }
            }

            if (method.getName().equalsIgnoreCase("getSQLUpdateStrings")) {
                ReflectionUtils.makeAccessible(method);
                Object insertQueries = ReflectionUtils.invokeMethod(method, persister);

                for (String queryText : (String []) insertQueries) {
                    System.out.println(queryText);
                }
            }
        }

    }
}
finally {
    if (em != null) {
        em.close();
    }
}