Hibernate之QBC检索和本地SQL检索

QBC查询就是通过使用Hibernate提供的Query By Criteria API来查询对象，这种API封装了SQL语句的动态拼装，对查询提供了更加面向对象的功能接口

本地SQL查询来完善HQL不能涵盖所有的查询特性。

====================代码区======================

测试类

 package com.yl.hibernate.test;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Set;

 import oracle.net.aso.e;

 import org.hibernate.Criteria;
 import org.hibernate.Query;
 import org.hibernate.Session;
 import org.hibernate.SessionFactory;
 import org.hibernate.Transaction;
 import org.hibernate.cfg.Configuration;
 import org.hibernate.criterion.Conjunction;
 import org.hibernate.criterion.Disjunction;
 import org.hibernate.criterion.MatchMode;
 import org.hibernate.criterion.Order;
 import org.hibernate.criterion.Projection;
 import org.hibernate.criterion.Projections;
 import org.hibernate.criterion.Restrictions;
 import org.hibernate.service.ServiceRegistry;
 import org.hibernate.service.ServiceRegistryBuilder;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;

 import com.yl.hibernate.entities.Department;
 import com.yl.hibernate.entities.Employee;

 public class HibernateTest {

     private SessionFactory sessionFactory;
     private Session session;
     private Transaction transaction;

     @Before
     public void init() {
         Configuration configuration = new Configuration().configure();
         ServiceRegistry serviceRegistry =
                 new ServiceRegistryBuilder().applySettings(configuration.getProperties())
                                             .buildServiceRegistry();

         sessionFactory = configuration.buildSessionFactory(serviceRegistry);

         session = sessionFactory.openSession();

         transaction = session.beginTransaction();
     }
     @After
     public void destory() {
         transaction.commit();

         session.close();

         sessionFactory.close();
     }

     @Test
     public void testQBC() {
         //1.创建一个Ctiteria对象
         Criteria criteria = session.createCriteria(Employee.class);
         //2.添加查询条件:在QBC中查询条件使用Criterion来表示
         //Criterion可以通过Restrictions 的静态方法得到
         criteria.add(Restrictions.eq("email", "PRESIDENT"));
         criteria.add(Restrictions.gt("salary", 500f));
         //3.执行查询
         Employee employee = (Employee) criteria.uniqueResult();
         System.out.println(employee);
     }

     @Test
     public void testQBC2() {

         Criteria criteria = session.createCriteria(Employee.class);
         //1.AND: 使用Conjunction表示
         //Conjunction 本身就是一个Criterion对象
         //且其中还可以添加Criterion对象
         Conjunction conjunction = Restrictions.conjunction();
         conjunction.add(Restrictions.like("name", "A", MatchMode.ANYWHERE));
         Department dept = new Department();
         dept.setId(20);
         conjunction.add(Restrictions.eq("dept", dept));
         System.out.println(conjunction);

         //2. OR
         Disjunction disjunction = Restrictions.disjunction();
         disjunction.add(Restrictions.ge("salary", 1000F));
         disjunction.add(Restrictions.isNotNull("email"));

         criteria.add(disjunction);
         criteria.add(conjunction);

         criteria.list();
         /**
          *  where
         (
             this_.SALARY>=?
             or this_.EMAIL is not null
         )
         and (
             this_.NAME like ?
             and this_.DEPT_ID=?
         )
          */
     }

     @Test
     public void testQBC3() {
         Criteria criteria = session.createCriteria(Employee.class);

         //统计查询： 使用Projection表示: 可以由Projections的静态方法得到
         criteria.setProjection(Projections.max("salary"));

         System.out.println(criteria.uniqueResult());
     }

     @Test
     public void testQBC4() {
         Criteria criteria = session.createCriteria(Employee.class);

         //1.添加排序
         criteria.addOrder(Order.asc("salary"));
         criteria.addOrder(Order.desc("email"));

         //2.添加分页
         int pageSize = 3;
         int pageNo = 2;
         criteria.setFirstResult((pageNo - 1) * pageSize)
                 .setMaxResults(pageSize)
                 .list();

     }

     @Test
     public void testNative() {
         String sql = "INSERT INTO YL_department VALUES(?, ?)";
         Query query = session.createSQLQuery(sql);

         query.setInteger(0, 50)
              .setString(1, "DEV")
              .executeUpdate();
     }

     @Test
     public void testHQLUpdate() {
         String hql = "DELETE FROM Department d WHERE d.id = :id";

         session.createQuery(hql).setInteger("id", 50)
                                 .executeUpdate();

     }
 }