Hibernate的基本CRUD

港控/mmm° 2022-06-16 04:26 315阅读 0赞

package cn.itcast.b_dao;
    
    import java.util.List;
    
    import org.hibernate.Criteria;
    import org.hibernate.Session;
    import org.hibernate.Transaction;
    
    import cn.itcast.a_helloworld.User;
    
    public class UserDao {
    	/**
    	 * 保存
    	 * 
    	 * @param user
    	 *            用户
    	 */
    	public void save(User user) {
    		Session session = HibernateUtils.opensession();
    		Transaction tx = null;
    		try {
    			tx = session.beginTransaction();// 开始事务
    			// 保存
    			session.save(user);
    			tx.commit();// 提交事务
    		} catch (RuntimeException e) {
    			tx.rollback();// 回滚事务
    			throw e;
    		} finally {
    			session.close();// 释放资源
    		}
    	}
    
    	/**
    	 * 更新
    	 * 
    	 * @param user
    	 *            用户
    	 */
    	public void update(User user) {
    		Session session = HibernateUtils.opensession();
    		Transaction tx = null;
    		try {
    			tx = session.beginTransaction();
    
    			// 操作
    			session.update(user);
    
    			tx.commit();// 提交事务
    		} catch (RuntimeException e) {
    			tx.rollback();// 回棍事务
    			throw e;
    		} finally {
    			session.close();// 释放资源
    		}
    	}
    
    	/**
    	 * 删除
    	 * 
    	 * @param id
    	 *            根据id删除数据
    	 */
    	public void delete(Integer id) {
    		Session session = HibernateUtils.opensession();
    		Transaction tx = null;
    		try {
    			tx = session.beginTransaction();
    
    			// 操作
    			Object user = session.get(User.class, id);// 要先获取到这个对象
    			session.delete(user);// 删除的是实体对象
    
    			tx.commit();// 提交事务
    		} catch (RuntimeException e) {
    			tx.rollback();// 回滚事务
    			throw e;
    		} finally {
    			session.close();// 释放资源
    		}
    	}
    
    	/**
    	 * 根据id查询一个User数据
    	 * 
    	 * @param id
    	 *            根据id查询数据
    	 * @return 返回一条User数据
    	 */
    	public User getById(Integer id) {
    		Session session = HibernateUtils.opensession();
    		Transaction tx = null;
    		try {
    			tx = session.beginTransaction();// 打开事务
    
    			// 操作
    			User user = (User) session.get(User.class, id);
    
    			tx.commit();// 提交事务
    			return user;
    		} catch (RuntimeException e) {
    			tx.rollback();// 回滚事务
    			throw e;
    		} finally {
    			session.close();// 释放资源;
    		}
    	}
    
    	/**
    	 * 查询所有用户
    	 * 
    	 * @return 返回所有用户
    	 */
    	@SuppressWarnings("unchecked")
    	public List<User> findAll() {
    		Session session = HibernateUtils.opensession();
    		Transaction tx = null;
    		try {
    			tx = session.beginTransaction();// 开始事务
    
    			// 方式一: 使用HQL查询
    			// List<User> list = session.createQuery(//
    			// "FROM User WHERE id=5 order by id")//
    			// .list();
    			// 方式二：使用Criteria查询
    			Criteria criteria = session.createCriteria(User.class);
    			// criteria.add(Restrictions.eq("id", 5));
    			// criteria.addOrder(Order.desc("id"));
    			List<User> list = criteria.list();
    
    			tx.commit();// 提交事务
    			return list;
    		} catch (RuntimeException e) {
    			tx.rollback();
    			// session.getTransaction().rollback();// 回滚事务
    			throw e;
    		} finally {
    			session.close();// 释放资源
    		}
    	}
    
    	/**
    	 * * 分页的查询数据列表
    	 * 
    	 * @param firstResult
    	 *            从结果列表中那个索引开始取数据
    	 * @param maxResult
    	 *            最多取多少条数据
    	 * @return 一页的数据列表 + 总计录数
    	 */
    	/**
    	 * @param firstResult
    	 * @param maxResult
    	 * @return
    	 */
    	@SuppressWarnings("unchecked")
    	public QueryResult findAll(Integer firstResult, Integer maxResult) {
    		Session session = HibernateUtils.opensession();
    		Transaction tx = null;
    		try {
    			tx = session.beginTransaction();// 开始事务
    
    			// 查询一页的数据列表
    			// 方式1
    			// Query query = session.createQuery("FROM User");
    			// query.setFirstResult(firstResult);
    			// query.setMaxResults(maxResult);
    			// List<User> list = query.list();// 操作
    
    			// 方式2
    			List<User> list = 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();
    
    			tx.commit();// 提交事务
    
    			// 返回结果
    			return new QueryResult(count.intValue(), list);
    		} catch (RuntimeException e) {
    			tx.rollback();// 回滚事务
    			throw e;
    		} finally {
    			session.close();// 释放资源
    		}
    	}
    }

package cn.itcast.b_dao;
    
    import org.hibernate.SessionFactory;
    import org.hibernate.cfg.Configuration;
    import org.hibernate.classic.Session;
    
    public class HibernateUtils {
    	// SessionFactory全局只需要一个就行了
    	private static SessionFactory sessionFactory;
    
    	static {
    		// Configuration cfg = new Configuration();
    		// cfg.configure();// 读取默认配置文件(hibernate.cfg.xml)
    		// // cfg.configure("hibernate.cfg.xml");//读取指定位置的配置文件
    		// sessionFactory = cfg.buildSessionFactory();//生成会话工厂
    
    		//初始化SessionFactory
    		sessionFactory = new Configuration()//
    				.configure()//
    				.buildSessionFactory();
    	}
    
    	/**
    	 * 获取全局唯一的SessionFactory
    	 * 
    	 * @return 返回SessionFactory
    	 */
    	public static SessionFactory getSessionFactory() {
    		return sessionFactory;
    	}
    
    	/**
    	 * 从全局唯一的SessionFactory中打开一个Session
    	 * 
    	 * @return 返回Session
    	 */
    	public static Session opensession() {
    		return sessionFactory.openSession();
    	}
    }

package cn.itcast.b_dao;
    
    import java.util.List;
    
    /**
     * 查询结果分页
     * 
     * @author 风清杨
     * @version V1.0
     */
    @SuppressWarnings("rawtypes")
    public class QueryResult {
    	private int count;// 总记录数
    	private List list;// 一页的数据
    
    	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;
    	}
    
    }

User.hbm.xml

<?xml version="1.0"?>
    <!DOCTYPE hibernate-mapping PUBLIC
            "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
            "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
    
    <hibernate-mapping package="cn.itcast.a_helloworld">
    	
    	<class name="User" table="t_user">
    		
    		<id name="id" type="int" column="id">
                
                <generator class="native"/>
    		</id>
    		<property name="name" type="string"  column="name"/>
    	</class>
    </hibernate-mapping>

Hibernate.cfg.xml

<!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 name="foo">
    		
    		
    		<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    		
    		<property name="connection.url">jdbc:mysql://localhost:3306/hibernate_20170423</property>
    		
    		<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
    		
    		<property name="connection.username">root</property>
    		
    		<property name="hibernate.connection.password">root</property>
    
    		
    		
    		<property name="hibernate.show_sql">true</property>
    		
    		<property name="hibernate.format_sql">false</property>
    
    		
    		<property name="hbm2ddl.auto">update</property>
    
    		
    		<mapping resource="cn/itcast/c_hbm_property/User.hbm.xml" />
    
    	</session-factory>
    </hibernate-configuration>