Hibernate相关的查询 --Hibernate框架基础

  1 package com.test;
  2 
  3 import java.util.List;
  4 
  5 import org.hibernate.Session;
  6 import org.junit.Test;
  7 
  8 import com.beans.Student;
  9 import com.utils.HbnUtils;
 10 
 11 public class QueryTest {
 12 
 13     /**
 14      * 添加测试数据
 15      */
 16     @Test
 17     public void test_01() {
 18         Session session = HbnUtils.getSession();
 19         try {
 20             session.beginTransaction();
 21             Student student1 = new Student("貂蝉", 20, 92);
 22             Student student2 = new Student("王昭君", 22, 93);
 23             Student student3 = new Student("杨玉环", 23, 94);
 24             Student student4 = new Student("李师师", 24, 95);
 25             Student student5 = new Student("苏小小", 25, 96);
 26             Student student6 = new Student("李师师", 28, 96);
 27             Student student7 = new Student("张云云", 20, 91);
 28             session.save(student1);
 29             session.save(student2);
 30             session.save(student3);
 31             session.save(student4);
 32             session.save(student5);
 33             session.save(student6);
 34             session.save(student7);
 35             session.getTransaction().commit();
 36         } catch (Exception e) {
 37             // TODO: handle exception
 38             session.getTransaction().rollback();
 39             e.printStackTrace();
 40         }
 41     }
 42 
 43     /**
 44      * 使用SQL语句查询学生信息（作比较）
 45      */
 46     @Test
 47     public void testQuery_SQL() {
 48         Session session = HbnUtils.getSession();
 49         try {
 50             session.beginTransaction();
 51             String sql = "SELECT tid,tname,tage,tscore FROM t_student ";
 52             List<Student> list = session.createSQLQuery(sql)
 53                     .addEntity(Student.class).list();
 54             for (Student student : list) {
 55                 System.out.println(student);
 56             }
 57             session.getTransaction().commit();
 58         } catch (Exception e) {
 59             // TODO: handle exception
 60             e.printStackTrace();
 61             session.getTransaction().rollback();
 62         }
 63     }
 64 
 65     /**
 66      * 使用HQL查询学生信息
 67      */
 68     @Test
 69     public void testQuery_HQL01() {
 70         Session session = HbnUtils.getSession();
 71         try {
 72             session.beginTransaction();
 73             String hql = "FROM Student ORDER BY tscore DESC";
 74             List<Student> list = session.createQuery(hql).list();
 75             for (Student student : list) {
 76                 System.out.println(student);
 77             }
 78             session.getTransaction().commit();
 79         } catch (Exception e) {
 80             // TODO: handle exception
 81             e.printStackTrace();
 82             session.getTransaction().rollback();
 83         }
 84     }
 85 
 86     /**
 87      * 查询指定字段的信息
 88      */
 89     @Test
 90     public void testQuery_HQL_02() {
 91         Session session = HbnUtils.getSession();
 92         try {
 93             session.beginTransaction();
 94             String hql = "FROM Student WHERE id=:id";// :后的id：属性名，Studetn：类名
 95             Student student = (Student) session.createQuery(hql)
 96                     .setInteger("id", 3).uniqueResult();
 97             System.out.println(student);
 98             session.getTransaction().commit();
 99         } catch (Exception e) {
100             // TODO: handle exception
101             e.printStackTrace();
102             session.getTransaction().rollback();
103         }
104     }
105 
106     /**
107      * 简单聚合查询
108      */
109     @Test
110     public void testQuery_HQL_03() {
111         Session session = HbnUtils.getSession();
112         try {
113             session.beginTransaction();
114             String hql = "SELECT COUNT(*) from Student";
115             Long count = (Long) session.createQuery(hql).uniqueResult();
116             System.out.println(count);// 打印有多少条数据
117             session.getTransaction().commit();
118         } catch (Exception e) {
119             // TODO: handle exception
120             e.printStackTrace();
121             session.getTransaction().rollback();
122         }
123     }
124 
125     /**
126      * 投影查询
127      */
128     @Test
129     public void testQuery_HQL04() {
130         Session session = HbnUtils.getSession();
131         try {
132             session.beginTransaction();
133             String hql = "SELECT new  Student(name,age) From Student";// 将查询到的字段通过构造方法封装到对象，然后保存在list中
134             List<Student> list = session.createQuery(hql).list();
135             for (Student student : list) {
136                 System.out.println(student);//只查询到name、age信息，其他则为默认
137             }
138             session.getTransaction().commit();
139         } catch (Exception e) {
140             // TODO: handle exception
141             e.printStackTrace();
142             session.getTransaction().rollback();
143         }
144     }
145 
146     /**
147      * 查每个年龄段的第一个人
148      */
149     @Test
150     public void testQuery_HQL05() {
151         Session session = HbnUtils.getSession();
152         try {
153             session.beginTransaction();
154             String hql = "FROM Student GROUP BY age";
155             List<Student> list = session.createQuery(hql).list();
156             for (Student student : list) {
157                 System.out.println(student);
158             }
159             session.getTransaction().commit();
160         } catch (Exception e) {
161             // TODO: handle exception
162             e.printStackTrace();
163             session.getTransaction().rollback();
164         }
165     }
166 
167     /**
168      * 查询有几个年龄段
169      */
170     @Test
171     public void testQuery_HQL06() {
172         Session session = HbnUtils.getSession();
173         try {
174             session.beginTransaction();
175             String hql= "select age from Student group by age";
176             List<Integer> list = session.createQuery(hql).list();
177             System.out.println(list);
178             session.getTransaction().commit();
179         } catch (Exception e) {
180             // TODO: handle exception
181             e.printStackTrace();
182             session.getTransaction().rollback();
183         }
184     }
185 
186     /**
187      * 查询年龄大于1人的年龄段
188      */
189     @Test
190     public void testQuery_HQL07() {
191         Session session = HbnUtils.getSession();
192         try {
193             session.beginTransaction();
194             String hql= "select age from Student group by age having count(age) > 1";
195             List<Integer> list = session.createQuery(hql).list();
196             System.out.println(list);
197             session.getTransaction().commit();
198         } catch (Exception e) {
199             // TODO: handle exception
200             e.printStackTrace();
201             session.getTransaction().rollback();
202         }
203     }
204 }