Hibernate的条件查询的几种方式

1、第一种，用？占位符，如：//登录(用?占位符)public List LoginUser(UserPO up)throws Exception{Session session = HibernateSessionFactory.getSession();String hql = "from UserPO where name = ? and pwd= ?";Query query = session.createQuery(hql);query.setString(0, up.getName());query.setString(1, up.getPwd());List list = query.list();session.close();return list;}2、用“：+命名”占位符，如：//登录(用"：命名"占位符)public List LoginUser2(UserPO up)throws Exception{Session session = HibernateSessionFactory.getSession();String hql = "from UserPO where name = :n and pwd= :p";Query query = session.createQuery(hql);query.setString("n", up.getName());query.setString("p", up.getPwd());List list = query.list();session.close();return list;}2.1、使用这种占位符还可以这样设值，如：//登录(用"：命名"占位符，用setParameter设值)public List LoginUser3(UserPO up)throws Exception{Session session = HibernateSessionFactory.getSession();String hql = "from UserPO where name = :n and pwd= :p";Query query = session.createQuery(hql);query.setParameter("n", up.getName());query.setParameter("p",up.getPwd());List list = query.list();session.close();return list;}使用这种方式不需要写明映射的类型，Hibernate会通过配置自动给我们转，但是由于Hibernate有两种日期格式：Date和TIMESTAMP，所以对于日期类型必须写明映射的类型。写法： 3、按照对象进行参数绑定，如： //登录(用"：命名"占位符，用setProperties设值,命名参数必须要与被绑定的属性名相同)public List LoginUser4(UserPO up)throws Exception{Session session = HibernateSessionFactory.getSession();String hql = "from UserPO where name = :name and pwd= :pwd";Query query = session.createQuery(hql);query.setProperties(up);List list = query.list();session.close();return list;}4、使用条件查询(Criteria)，如： //登录(用条件查询 Criteria)完全脱离sql语句和hql语句public List LoginUser5(UserPO up)throws Exception{Session session = HibernateSessionFactory.getSession();Criteria cri = session.createCriteria(UserPO.class);cri.add(Restrictions.eq("name", up.getName()));cri.add(Restrictions.eq("pwd", up.getPwd()));List list = cri.list();session.close();return list;} 5、离线条件查询，如：//登录(用离线条件查询 DetachedCriteria)public List LoginUser6(UserPO up)throws Exception{Session session = HibernateSessionFactory.getSession();DetachedCriteria dc = DetachedCriteria.forClass(UserPO.class);dc.add(Restrictions.eq("name", up.getName()));dc.add(Restrictions.eq("pwd", up.getPwd()));Criteria cri = dc.getExecutableCriteria(session);List list = cri.list();session.close();return list;}使用离线可以将其写在业务层，以参数的形式传入，以减少DAO的代码。6、分页查询：分页查询是数据库应用中的处理方式，query和criteria接口都提供了用于分页查询的方法：1)setFirstResult(int):指定从哪一个对象开始查询，参数是索引位置，从0开始。2)setMaxResult(int):指定一次最多查询的对象数量。 // 首页上最新商品的查询public List<Product> findNew() {// 使用离线条件查询:DetachedCriteria criteria = DetachedCriteria.forClass(Product.class);// 按日期进行倒序排序:criteria.addOrder(Order.desc("pdate"));// 执行查询:List<Product> list = this.getHibernateTemplate().findByCriteria(criteria, 0, 10);return list;}// 根据商品ID查询商品public Product findByPid(Integer pid) {return this.getHibernateTemplate().get(Product.class, pid);}// 根据分类id查询商品的个数public int findCountCid(Integer cid) {String hql = "select count(*) from Product p where p.categorySecond.category.cid = ?";List<Long> list = this.getHibernateTemplate().find(hql,cid);if(list != null && list.size() > 0){return list.get(0).intValue();}return 0;}// 根据分类id查询商品的集合public List<Product> findByPageCid(Integer cid, int begin, int limit) {// select p.* from category c,categorysecond cs,product p where c.cid = cs.cid and cs.csid = p.csid and c.cid = 2// select p from Category c,CategorySecond cs,Product p where c.cid = cs.category.cid and cs.csid = p.categorySecond.csid and c.cid = ?String hql = "select p from Product p join p.categorySecond cs join cs.category c where c.cid = ?";// 分页另一种写法:List<Product> list = this.getHibernateTemplate().execute(new PageHibernateCallback<Product>(hql, new Object[]{cid}, begin, limit));if(list != null && list.size() > 0){return list;}return null;}

封装的公共类

package cn.itcast.shop.utils;import java.sql.SQLException;import java.util.List;import org.hibernate.HibernateException;import org.hibernate.Query;import org.hibernate.Session;import org.springframework.orm.hibernate3.HibernateCallback;public class PageHibernateCallback<T> implements HibernateCallback<List<T>>{private String hql;private Object[] params;private int startIndex;private int pageSize;public PageHibernateCallback(String hql, Object[] params,int startIndex, int pageSize) {super();this.hql = hql;this.params = params;this.startIndex = startIndex;this.pageSize = pageSize;}public List<T> doInHibernate(Session session) throws HibernateException,SQLException {//1 执行hql语句Query query = session.createQuery(hql);//2 实际参数if(params != null){for(int i = 0 ; i < params.length ; i ++){query.setParameter(i, params[i]);}}//3 分页query.setFirstResult(startIndex);query.setMaxResults(pageSize);return query.list();}}

public class PageBean<T> {private int page;// 当前页数private int totalCount; // 总记录数private int totalPage; // 总页数private int limit;// 每页显示的记录数private List<T> list; // 每页显示数据的集合.public int getPage() {return page;}public void setPage(int page) {this.page = page;}public int getTotalCount() {return totalCount;}public void setTotalCount(int totalCount) {this.totalCount = totalCount;}public int getTotalPage() {return totalPage;}public void setTotalPage(int totalPage) {this.totalPage = totalPage;}public int getLimit() {return limit;}public void setLimit(int limit) {this.limit = limit;}public List<T> getList() {return list;}public void setList(List<T> list) {this.list = list;}}