标签:des style blog io ar color os 使用 sp
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
1 package com.yl.hibernate.test; 2 3 4 import java.util.ArrayList; 5 import java.util.Arrays; 6 import java.util.LinkedHashSet; 7 import java.util.List; 8 import java.util.Set; 9 10 import oracle.net.aso.e; 11 12 import org.hibernate.Criteria; 13 import org.hibernate.Query; 14 import org.hibernate.Session; 15 import org.hibernate.SessionFactory; 16 import org.hibernate.Transaction; 17 import org.hibernate.cfg.Configuration; 18 import org.hibernate.criterion.Conjunction; 19 import org.hibernate.criterion.Disjunction; 20 import org.hibernate.criterion.MatchMode; 21 import org.hibernate.criterion.Order; 22 import org.hibernate.criterion.Projection; 23 import org.hibernate.criterion.Projections; 24 import org.hibernate.criterion.Restrictions; 25 import org.hibernate.service.ServiceRegistry; 26 import org.hibernate.service.ServiceRegistryBuilder; 27 import org.junit.After; 28 import org.junit.Before; 29 import org.junit.Test; 30 31 import com.yl.hibernate.entities.Department; 32 import com.yl.hibernate.entities.Employee; 33 34 public class HibernateTest { 35 36 private SessionFactory sessionFactory; 37 private Session session; 38 private Transaction transaction; 39 40 @Before 41 public void init() { 42 Configuration configuration = new Configuration().configure(); 43 ServiceRegistry serviceRegistry = 44 new ServiceRegistryBuilder().applySettings(configuration.getProperties()) 45 .buildServiceRegistry(); 46 47 sessionFactory = configuration.buildSessionFactory(serviceRegistry); 48 49 session = sessionFactory.openSession(); 50 51 transaction = session.beginTransaction(); 52 } 53 @After 54 public void destory() { 55 transaction.commit(); 56 57 session.close(); 58 59 sessionFactory.close(); 60 } 61 62 63 @Test 64 public void testQBC() { 65 //1.创建一个Ctiteria对象 66 Criteria criteria = session.createCriteria(Employee.class); 67 //2.添加查询条件:在QBC中查询条件使用Criterion来表示 68 //Criterion可以通过Restrictions 的静态方法得到 69 criteria.add(Restrictions.eq("email", "PRESIDENT")); 70 criteria.add(Restrictions.gt("salary", 500f)); 71 //3.执行查询 72 Employee employee = (Employee) criteria.uniqueResult(); 73 System.out.println(employee); 74 } 75 76 @Test 77 public void testQBC2() { 78 79 Criteria criteria = session.createCriteria(Employee.class); 80 //1.AND: 使用Conjunction表示 81 //Conjunction 本身就是一个Criterion对象 82 //且其中还可以添加Criterion对象 83 Conjunction conjunction = Restrictions.conjunction(); 84 conjunction.add(Restrictions.like("name", "A", MatchMode.ANYWHERE)); 85 Department dept = new Department(); 86 dept.setId(20); 87 conjunction.add(Restrictions.eq("dept", dept)); 88 System.out.println(conjunction); 89 90 //2. OR 91 Disjunction disjunction = Restrictions.disjunction(); 92 disjunction.add(Restrictions.ge("salary", 1000F)); 93 disjunction.add(Restrictions.isNotNull("email")); 94 95 criteria.add(disjunction); 96 criteria.add(conjunction); 97 98 criteria.list(); 99 /** 100 * where 101 ( 102 this_.SALARY>=? 103 or this_.EMAIL is not null 104 ) 105 and ( 106 this_.NAME like ? 107 and this_.DEPT_ID=? 108 ) 109 */ 110 } 111 112 @Test 113 public void testQBC3() { 114 Criteria criteria = session.createCriteria(Employee.class); 115 116 //统计查询: 使用Projection表示: 可以由Projections的静态方法得到 117 criteria.setProjection(Projections.max("salary")); 118 119 System.out.println(criteria.uniqueResult()); 120 } 121 122 @Test 123 public void testQBC4() { 124 Criteria criteria = session.createCriteria(Employee.class); 125 126 //1.添加排序 127 criteria.addOrder(Order.asc("salary")); 128 criteria.addOrder(Order.desc("email")); 129 130 //2.添加分页 131 int pageSize = 3; 132 int pageNo = 2; 133 criteria.setFirstResult((pageNo - 1) * pageSize) 134 .setMaxResults(pageSize) 135 .list(); 136 137 } 138 139 @Test 140 public void testNative() { 141 String sql = "INSERT INTO YL_department VALUES(?, ?)"; 142 Query query = session.createSQLQuery(sql); 143 144 query.setInteger(0, 50) 145 .setString(1, "DEV") 146 .executeUpdate(); 147 } 148 149 @Test 150 public void testHQLUpdate() { 151 String hql = "DELETE FROM Department d WHERE d.id = :id"; 152 153 session.createQuery(hql).setInteger("id", 50) 154 .executeUpdate(); 155 156 } 157 }
标签:des style blog io ar color os 使用 sp
原文地址:http://www.cnblogs.com/dreamfree/p/4138711.html