选择使用休眠 [英] Select using hibernate

问题描述

在select语句中，我使用 transaction.commit（）在互联网上看到了一些Hibernate的例子。以下是示例代码。

I saw few examples over internet of Hibernate using transaction.commit() for select statements. Below is the example code.

public static List<?> list(Class<?> className,int start,int limit,SearchFilter[] searchFilter){
    Session session = HibernateUtil.getSessionFactory().openSession();
    Transaction transaction = null; 

    try {
        transaction = session.beginTransaction();

        Criteria criteria = session.createCriteria(className);
        criteria.setFirstResult(start);
        criteria.setMaxResults(limit);

        for(SearchFilter sf : searchFilter){
            String[] values = sf.getValue();
            if(values != null){
                if(values.length == 1) {
                    criteria.add(Restrictions.eq(sf.getField(), values[0]));
                }else{
                    criteria.add(Restrictions.in(sf.getField(), values));
                }
            }
        }

        List<?> Objects = criteria.list();
        transaction.commit();

        return Objects;
    }catch (Exception e) {
        transaction.rollback();
        e.printStackTrace();
    }finally{
        session.close();
    }

    return null;
}

为什么我们要为select语句开始并提交事务？

Why do we do beginning and committing a transaction for select statement?

推荐答案

一切都发生在一个交易的范围。有时软件会自动为你管理一笔交易，但休眠不会。无论是否只读，休眠时，您必须打开并关闭交易。

everything happens within the scope of a transaction. sometimes software automatically manages a transaction for you, but hibernate does not. whether read-only or not, in hibernate you must open and close transactions.

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