Hibernate 通用类

GenericDaoHibernate.java

package com.shadow.oa.dao.hibernate;

import java.io.Serializable;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;
import org.springframework.orm.ObjectRetrievalFailureException;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.shadow.oa.dao.GenericDao;

/**
 * This class serves as the Base class for all other DAOs - namely to hold
 * common CRUD methods that they might all use. You should only need to extend
 * this class when your require custom CRUD logic.
 * 
 * <p>
 * To register this class in your Spring context file, use the following XML.
 * 
 * <pre>
 *      &lt;bean id=&quot;fooDao&quot; class=&quot;com.shadow.app.dao.hibernate.GenericDaoHibernate&quot;&gt;
 *          &lt;constructor-arg value=&quot;com.shadow.app.model.Foo&quot;/&gt;
 *          &lt;property name=&quot;sessionFactory&quot; ref=&quot;sessionFactory&quot;/&gt;
 *      &lt;/bean&gt;
 * </pre>
 * 
 * @author <a href="mailto:[e-mail]">Bryan Noll</a>
 * @param <T>
 *            a type variable
 * @param <PK>
 *            the primary key for that type
 */
public class GenericDaoHibernate<T, PK extends Serializable> extends
		HibernateDaoSupport implements GenericDao<T, PK> {
	/**
	 * Log variable for all child classes. Uses LogFactory.getLog(getClass())
	 * from Commons Logging
	 */
	protected final Log log = LogFactory.getLog(getClass());
	private Class<T> persistentClass;

	/**
	 * Constructor that takes in a class to see which type of entity to persist
	 * 
	 * @param persistentClass
	 *            the class type you'd like to persist
	 */
	public GenericDaoHibernate(final Class<T> persistentClass) {		
		this.persistentClass = persistentClass;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public List<T> getAll() {
		return super.getHibernateTemplate().loadAll(this.persistentClass);
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public List<T> getAllDistinct() {
		Collection result = new LinkedHashSet(getAll());
		return new ArrayList(result);
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public T get(PK id) {
		T entity = (T) super.getHibernateTemplate().get(this.persistentClass,
				id);

		if (entity == null) {
			log.warn("Uh oh, '" + this.persistentClass + "' object with id '"
					+ id + "' not found...");
			throw new ObjectRetrievalFailureException(this.persistentClass, id);
		}

		return entity;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public boolean exists(PK id) {
		T entity = (T) super.getHibernateTemplate().get(this.persistentClass,
				id);
		return entity != null;
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public T save(T object) {
		return (T) super.getHibernateTemplate().merge(object);
	}

	/**
	 * {@inheritDoc}
	 */
	public void remove(PK id) {
		super.getHibernateTemplate().delete(this.get(id));
	}

	/**
	 * {@inheritDoc}
	 */
	@SuppressWarnings("unchecked")
	public List<T> findByNamedQuery(String queryName,
			Map<String, Object> queryParams) {
		String[] params = new String[queryParams.size()];
		Object[] values = new Object[queryParams.size()];
		int index = 0;
		Iterator<String> i = queryParams.keySet().iterator();
		while (i.hasNext()) {
			String key = i.next();
			params[index] = key;
			values[index++] = queryParams.get(key);
		}
		return getHibernateTemplate().findByNamedQueryAndNamedParam(queryName,
				params, values);
	}

	@SuppressWarnings("unchecked")
	public List<T> find(final String hsql, final int firstRow, final int maxRow)
			throws Exception {
		return getHibernateTemplate().executeFind(new HibernateCallback() {
			public Object doInHibernate(Session s) throws HibernateException,
					SQLException {
				Query query = s.createQuery(hsql);
				query.setFirstResult(firstRow);
				query.setMaxResults(maxRow);
				List list = query.list();
				return list;
			}
		});
	}

	public Integer getNum(final Object obj, final String field, final Integer id) {
		return (Integer) getHibernateTemplate().execute(
				new HibernateCallback() {
					public Object doInHibernate(Session s)
							throws HibernateException, SQLException {
						Criteria criteria = s.createCriteria(obj.getClass());
						criteria.setProjection(Projections.rowCount());
						criteria.add(Restrictions.eq(field, id));
						return criteria.uniqueResult();
					}
				});
	}

}