Hibernate之实现数据库的基本操作

配置过程省略。

数据库连接的公共类HibernateUtils.java

package test.hibernate.dao;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtils {

	private static SessionFactory sessionFactory;

	static {
		// Configuration configuration=new Configuration();
		// configuration.configure();//读取默认的文件hibernate.cfg.xml
		// // configuration.configure("hibernate.cfg.xml");读取指定文件
		// sessionFactory=configuration.buildSessionFactory();
		sessionFactory = new Configuration()//
				.configure()//
				.buildSessionFactory();
	}

	/*
	 * 获得一个全局唯一的SessionFactory
	 *
	 * @return
	 */

	public static SessionFactory getSessionFactory() {
		return sessionFactory;
	}

	/*
	 * 从全局SessionFactory中打开一个Session
	 */
	public static Session openSession() {
		return sessionFactory.openSession();
	}

	public static void setSessionFactory(SessionFactory sessionFactory) {
		HibernateUtils.sessionFactory = sessionFactory;
	}

}

QueryResult.java

package test.hibernate.dao;

import java.util.List;

public class QueryResult {

	private int count;
	private List list;

	public QueryResult(int count, List list) {
		this.count = count;
		this.list = list;
	}

	public int getCount() {
		return count;
	}

	public void setCount(int count) {
		this.count = count;
	}

	public List getList() {
		return list;
	}

	public void setList(List list) {
		this.list = list;
	}

}

业务实现类UserDao.java

package test.hibernate.dao;

import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Restrictions;

import test.hibernate.domain.User;

/**
 * @author LinDL
 *
 */
public class UserDao {

	public void save(User user) {
		Session session = HibernateUtils.openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();
			session.save(user);
			transaction.commit();
		} catch (RuntimeException e) {
			// TODO: handle exception
			transaction.rollback();
			throw e;
		} finally {

		}
		session.close();
	}

	public void update(User user) {
		Session session = HibernateUtils.openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();
			session.update(user);
			transaction.commit();
		} catch (RuntimeException e) {
			// TODO: handle exception
			transaction.rollback();
			throw e;
		} finally {

		}
		session.close();
	}

	public void delete(int id) {
		Session session = HibernateUtils.openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();
			User user = (User) session.get(User.class, id);// 要先获取到实体对象
			session.delete(user);// 删除的是实体对象
			transaction.commit();
		} catch (RuntimeException e) {
			// TODO: handle exception
			transaction.rollback();
			throw e;
		} finally {

		}
		session.close();
	}

	/**
	 * @param id
	 * @return
	 */
	public User getById(int id) {
		Session session = HibernateUtils.openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();
			User user = (User) session.get(User.class, id);
			transaction.commit();
			return user;
		} catch (RuntimeException e) {
			// TODO: handle exception
			transaction.rollback();
			throw e;
		} finally {
			session.close();
		}
	}

	/**
	 * @return
	 */
	public List<User> findAll() {
		Session session = HibernateUtils.openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();
			// 使用HQL查询
			// List<User> all = session.createQuery("from User").list();
			// 使用面向对象的方式查询
			Criteria criteria = session.createCriteria(User.class);
			// criteria.add(Restrictions.eq("id", 5));// 添加限制条件，查询id等于5的记录
			// criteria.add(Restrictions.ge("id", 6));//
			// 查询id大于等于6的记录，lt表小于,le表小于等于
			// criteria.addOrder(Order.asc("id"));// 添加排序条件

			List<User> all = criteria.list();

			transaction.commit();
			return all;
		} catch (RuntimeException e) {
			// TODO: handle exception
			transaction.rollback();
			throw e;
		} finally {
			session.close();
		}
	}

	/**
	 * @param firstResult
	 * @param maxResult
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public QueryResult findAll(int firstResult, int maxResult) {
		Session session = HibernateUtils.openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();
			// 使用HQL查询
			// Query query = (Query) session.createQuery("from User");
			// query.setFirstResult(firstResult);
			// query.setMaxResults(maxResult);
			// List<User> all = query.list();
			List<User> all = session.createQuery("from User")
					.setFirstResult(firstResult)//
					.setMaxResults(maxResult)//
					.list();

			// 查询总记录数
			Long count = (Long) session
					.createQuery("select count(*) from User").uniqueResult();
			transaction.commit();

			return new QueryResult(count.intValue(), all);
		} catch (RuntimeException e) {
			// TODO: handle exception
			transaction.rollback();
			throw e;
		} finally {
			session.close();
		}
	}
}

测试类

package test.hibernate.dao;

import static org.junit.Assert.*;

import java.util.List;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import test.hibernate.domain.User;

public class UserDaoTest {

	UserDao userDao = new UserDao();

	@Test
	public void testSave() {
		User user = new User();
		// user.setName("张三");
		// userDao.save(user);
		for (int i = 1; i < 30; i++) {
			user.setId(i);
			user.setName("test" + i);
			userDao.save(user);
		}
	}

	@Test
	public void testUpdate() {
		User user = userDao.getById(2);
		user.setName("历史");
		userDao.update(user);
	}

	@Test
	public void testDelete() {
		userDao.delete(2);
	}

	@Test
	public void testGetById() {
		User user = userDao.getById(1);
		System.out.println(user);
	}

	@Test
	public void testFindAll() {
		List<User> list = userDao.findAll();
		for (User user : list) {
			System.out.println(user);
		}
	}

	@Test
	public void testFindAllIntInt() {
		// QueryResult queryResult = userDao.findAll(0, 10);
		// QueryResult queryResult=userDao.findAll(10, 10);
		QueryResult queryResult = userDao.findAll(20, 10);
		System.out.println("总记录数" + queryResult.getCount());
		for (Object user : queryResult.getList()) {
			System.out.println(user);
		}
	}

}

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