创建实体类对象：
package domain; import java.util.HashSet; import java.util.Set; //客户实体 public class Customer { private Long cust_id; private String cust_name; private String cust_source; private String cust_industry; private String cust_level; private String cust_linkman; private String cust_phone; private String cust_mobile; //使用set集合,表达一对多关系 private Set<LinkMan> linkMens = new HashSet<LinkMan>(); public Set<LinkMan> getLinkMens() { return linkMens; } public void setLinkMens(Set<LinkMan> linkMens) { this.linkMens = linkMens; } public Long getCust_id() { return cust_id; } public void setCust_id(Long cust_id) { this.cust_id = cust_id; } public String getCust_name() { return cust_name; } public void setCust_name(String cust_name) { this.cust_name = cust_name; } public String getCust_source() { return cust_source; } public void setCust_source(String cust_source) { this.cust_source = cust_source; } public String getCust_industry() { return cust_industry; } public void setCust_industry(String cust_industry) { this.cust_industry = cust_industry; } public String getCust_level() { return cust_level; } public void setCust_level(String cust_level) { this.cust_level = cust_level; } public String getCust_linkman() { return cust_linkman; } public void setCust_linkman(String cust_linkman) { this.cust_linkman = cust_linkman; } public String getCust_phone() { return cust_phone; } public void setCust_phone(String cust_phone) { this.cust_phone = cust_phone; } public String getCust_mobile() { return cust_mobile; } public void setCust_mobile(String cust_mobile) { this.cust_mobile = cust_mobile; } @Override public String toString() { return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]"; } }
自定义工具类：
package utils; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; public class HibernateUtils { private static SessionFactory sf; static{ //1 创建,调用空参构造 Configuration conf = new Configuration().configure(); //2 根据配置信息,创建 SessionFactory对象 sf = conf.buildSessionFactory(); } //获得session => 获得全新session public static Session openSession(){ //3 获得session Session session = sf.openSession(); return session; } //获得session => 获得与线程绑定的session public static Session getCurrentSession(){ //3 获得session Session session = sf.getCurrentSession(); return session; } }
测试类示例：
基本语法：
package criteria; import java.util.List; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.Transaction; import org.hibernate.criterion.Order; import org.hibernate.criterion.Projections; import org.hibernate.criterion.Restrictions; import org.junit.Test; import domain.Customer; import utils.HibernateUtils; //学习Criteria语法 public class Demo { @Test //基本语法 public void fun1(){ Session session = HibernateUtils.openSession(); Transaction tx = session.beginTransaction(); //---------------------------------------------------- Criteria c = session.createCriteria(Customer.class); List<Customer> list = c.list(); System.out.println(list); //---------------------------------------------------- tx.commit(); session.close(); } @Test //条件语法 // > gt // >= ge // < lt // <= le // == eq // != ne // in in // between and between // like like // is not null isNotNull // is null isNull // or or // and and public void fun2(){ Session session = HibernateUtils.openSession(); Transaction tx = session.beginTransaction(); //---------------------------------------------------- Criteria c = session.createCriteria(Customer.class); // c.add(Restrictions.idEq(2l)); c.add(Restrictions.eq("cust_id",2l)); List<Customer> list = c.list(); System.out.println(list); //---------------------------------------------------- tx.commit(); session.close(); } @Test //分页语法 - 与HQL一样 public void fun3(){ Session session = HibernateUtils.openSession(); Transaction tx = session.beginTransaction(); //---------------------------------------------------- Criteria c = session.createCriteria(Customer.class); //limit ?,? c.setFirstResult(0); c.setMaxResults(2); List<Customer> list = c.list(); System.out.println(list); //---------------------------------------------------- tx.commit(); session.close(); } @Test //排序语法 public void fun4(){ Session session = HibernateUtils.openSession(); Transaction tx = session.beginTransaction(); //---------------------------------------------------- Criteria c = session.createCriteria(Customer.class); c.addOrder(Order.asc("cust_id"));//升序 //c.addOrder(Order.desc("cust_id"));降序 List<Customer> list = c.list(); System.out.println(list); //---------------------------------------------------- tx.commit(); session.close(); } @Test //统计语法 public void fun5(){ Session session = HibernateUtils.openSession(); Transaction tx = session.beginTransaction(); //---------------------------------------------------- Criteria c = session.createCriteria(Customer.class); //设置查询目标（聚合函数） c.setProjection(Projections.rowCount()); List list = c.list(); System.out.println(list); //---------------------------------------------------- tx.commit(); session.close(); } }
离线查询：
传统criteria对象创建依赖于session，前端传递查询条件依次经过WEB、SERVICE层到DAO层，
在DAO层组装查询条件到criteria后执行查询
离线的criteria对象，于session无关，凭空创建，可以在WEB层创建criteria对象并组装查询条件，
这时候直接传递criteria对象到DAO层查询即可，这时候就做到了一个DAO方法适用于所有查询
package criteria; import java.util.List; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.Transaction; import org.hibernate.criterion.DetachedCriteria; import org.hibernate.criterion.Order; import org.hibernate.criterion.Projections; import org.hibernate.criterion.Restrictions; import org.junit.Test; import domain.Customer; import utils.HibernateUtils; //学习离线Criteria public class Demo2 { @Test public void fun1(){ //Service/web层 DetachedCriteria dc = DetachedCriteria.forClass(Customer.class); dc.add(Restrictions.idEq(5l));//拼装条件(全部与普通Criteria一致) //---------------------------------------------------- Session session = HibernateUtils.openSession(); Transaction tx = session.beginTransaction(); //---------------------------------------------------- //Dao层 Criteria c = dc.getExecutableCriteria(session); List list = c.list(); System.out.println(list); //---------------------------------------------------- tx.commit(); session.close(); } }
