Hibernate - 交易的样板代码

Posted 2023-04-18

【中文标题】Hibernate - 交易的样板代码

【英文标题】：Hibernate - Boilerplate code for transactions

【发布时间】：2013-01-12 01:36:23

【问题描述】：

我已经为数据库 CRUD 操作编写了这个服务类。

可见的公共类 CompanyServiceImpl 扩展 PersistentRemoteService 实现 CompanyService

    private GileadHibernateUtil gileadHibernateUtil;

    public CompanyServiceImpl() 
        gileadHibernateUtil = new GileadHibernateUtil();
        setBeanManager(gileadHibernateUtil.getPersistentBeanManager());
    

    @Override
    public void addCompany(Company newCompany) 
        Objects.requireNonNull(newCompany, "newCompany is null.");

        Session session = gileadHibernateUtil.getCurrentSession();
        Transaction transaction = null;
        try 
            transaction = session.beginTransaction();
            session.persist(newCompany);
            session.getTransaction().commit();
         finally 
            if (transaction.isActive()) 
                transaction.rollback();
            
            session.close();
        
    

    @Override
    public Company updateCompany(Company company) 
        Objects.requireNonNull(company, "company is null.");

        Session session = gileadHibernateUtil.getCurrentSession();
        Transaction transaction = null;
        Company managedCompany = null;

        try 
            transaction = session.beginTransaction();
            managedCompany = (Company) session.merge(company);
            session.getTransaction().commit();
         finally 
            if (transaction.isActive()) 
                transaction.rollback();
            
        

        return managedCompany;
    

    @Override
    public void deleteCompany(Company company) 
        Objects.requireNonNull(company, "company is null.");

        Session session = gileadHibernateUtil.getCurrentSession();
        Transaction transaction = null;

        try 
            transaction = session.beginTransaction();
            session.delete(company);
            session.getTransaction().commit();
         finally 
            if (transaction.isActive()) 
                transaction.rollback();
            
        

    

    @Override
    public Company findCompany(int companyId) 
        if (companyId <= 0) 
            throw new IllegalArgumentException("companyId must be a positive integer.");
        

        Session session = gileadHibernateUtil.getCurrentSession();
        Transaction transaction = null;
        Company company = null;

        try 
            transaction = session.beginTransaction();
            company = (Company) session.get(Company.class, companyId);
            session.getTransaction().commit();
         finally 
            if (transaction.isActive()) 
                transaction.rollback();
            
        
        return company;
    

    @Override
    public List<Company> findMatchingCompanies(String companyName) 

        Session session = gileadHibernateUtil.getCurrentSession();
        Transaction transaction = null;
        List<Company> matchingCompanies = null;

        try 
            transaction = session.beginTransaction();
            Criteria searchCriteria = session.createCriteria(Company.class).add(
                    Restrictions.or(Restrictions.like("code", companyName), Restrictions.like("name", companyName)));
            session.getTransaction().commit();

            matchingCompanies = searchCriteria.list();
         finally 
            if (transaction.isActive()) 
                transaction.rollback();
            
        

        return matchingCompanies;
    

    @Override
    public List<Company> findAllCompanies() 

        Session session = gileadHibernateUtil.getCurrentSession();
        Transaction transaction = null;
        List<Company> companies = null;

        try 
            transaction = session.beginTransaction();
            Criteria searchCriteria = session.createCriteria(Company.class);
            session.getTransaction().commit();

            companies = searchCriteria.list();
         finally 
            if (transaction.isActive()) 
                transaction.rollback();
            
        
        return companies;
    

我决定不使用单独的 DAO 层。它是一个小应用程序，我不会从 Hibernate 切换。它所包含的只是 Hibernate 会话命令。开始和结束事务仍然来自业务层。所以，Hibernate 几乎可以作为我的 DAO 层。 困扰我的是看似样板的交易代码，必须在每个 CRUD 方法中编写。 这是更好的方法，还是无论如何都要重复的最少代码量？

【问题讨论】：

你考虑过使用 Spring 的 Hibernate 支持框架吗？

@ToddMurray 目前，它不是一个选项。这是主要问题。

【参考方案1】：

如果您使用的是 spring 并且能够使用注解。提供的链接上有一篇很好的文章，它展示了如何使用注释来包装事务中的方法。

http://springinpractice.com/2008/03/18/annotation-based-transactions-in-spring/

同时使用 spring 和 hibernate 将使您的代码看起来更干净，并且看起来像下面的内容。

@Override
@Transactional
public void addCompany(Company newCompany) 
    Objects.requireNonNull(newCompany, "newCompany is null.");
    Session session = gileadHibernateUtil.getCurrentSession();
    session.persist(newCompany);
    //session.close(); this line would also not be needed because the session would close automatically when the transaction is complete.

【讨论】：

是的。我在几个地方读到 Spring 将帮助清理代码。但是，我现在不应该使用 Spring。那我有什么选择呢？

不确定声明式事务还有哪些其他替代方案。您可能想尝试某种 aop 解决方案。但这也需要另一个库，您可能无法像 AspectJ 那样使用它。

好的。我想我会等一天才能接受这个正确答案。

【参考方案2】：

没有弹簧，这样的事情可以使用

java.util.function.Function

 public static Object transactionExecutor(Function<Session, Object> toRun) 
    Session session = null;
    Object result = null;
    try 
        session = getSession();
        final Transaction tx = session.beginTransaction();
        result = toRun.apply(session);
        session.flush();
        tx.commit();
        return result;
     catch (HibernateException he) 
        Transaction tx = session.getTransaction();
        tx.rollback();
     finally 

        session.close();
    
    return result;
 


 public static void save(final Students S) 
    Function<Session, Object> toRun = new Function<Session, Object>() 
        @Override
        public Object apply(final Session t) 
        t.save(S);
        return S.getId();
        
    ;
    int saveID = (int)transactionExecutor(toRun);