HQL（Hibernate Query Language）

 1 package com.bjsxt.hibernate;
 2 
 3 import javax.persistence.Entity;
 4 import javax.persistence.GeneratedValue;
 5 import javax.persistence.Id;
 6 
 7 @Entity
 8 public class Category {
 9     
10     private Integer id;
11     
12     private String name;
13 
14     @Id
15     @GeneratedValue
16     public Integer getId() {
17         return id;
18     }
19 
20     public void setId(Integer id) {
21         this.id = id;
22     }
23 
24     public String getName() {
25         return name;
26     }
27 
28     public void setName(String name) {
29         this.name = name;
30     }
31 }

 1 package com.bjsxt.hibernate;
 2 
 3 import java.util.Date;
 4 
 5 import javax.persistence.Entity;
 6 import javax.persistence.FetchType;
 7 import javax.persistence.GeneratedValue;
 8 import javax.persistence.Id;
 9 import javax.persistence.ManyToOne;
10 
11 @Entity
12 public class Topic {
13     
14     private Integer id;
15     
16     private String title;
17     
18     private Category category;
19     
20     private Date createDate;
21 
22     @Id
23     @GeneratedValue
24     public Integer getId() {
25         return id;
26     }
27 
28     public void setId(Integer id) {
29         this.id = id;
30     }
31 
32     public String getTitle() {
33         return title;
34     }
35 
36     public void setTitle(String title) {
37         this.title = title;
38     }
39 
40     @ManyToOne(fetch=FetchType.LAZY)
41     public Category getCategory() {
42         return category;
43     }
44 
45     public void setCategory(Category category) {
46         this.category = category;
47     }
48 
49     public Date getCreateDate() {
50         return createDate;
51     }
52 
53     public void setCreateDate(Date createDate) {
54         this.createDate = createDate;
55     }
56 }

 1 package com.bjsxt.hibernate;
 2 
 3 import javax.persistence.Entity;
 4 import javax.persistence.GeneratedValue;
 5 import javax.persistence.Id;
 6 import javax.persistence.ManyToOne;
 7 
 8 @Entity
 9 public class Msg {
10     
11     private Integer id;
12     
13     private String cont;
14     
15     private Topic topic;
16 
17     @Id
18     @GeneratedValue
19     public Integer getId() {
20         return id;
21     }
22 
23     public void setId(Integer id) {
24         this.id = id;
25     }
26 
27     public String getCont() {
28         return cont;
29     }
30 
31     public void setCont(String cont) {
32         this.cont = cont;
33     }
34 
35     @ManyToOne
36     public Topic getTopic() {
37         return topic;
38     }
39 
40     public void setTopic(Topic topic) {
41         this.topic = topic;
42     }
43 }

 1 package com.bjsxt.hibernate;
 2 
 3 //VO(Value Object) DTO(Data Transfer Object)
 4 public class MsgInfo {    
 5 
 6     private Integer id;
 7     
 8     private String cont;
 9     
10     private String topicName;
11     
12     private String categoryName;
13     
14     public MsgInfo(Integer id,String cont,String topicName,String categoryName){
15         this.id = id;
16         this.cont = cont;
17         this.topicName = topicName;
18         this.categoryName = categoryName;
19     }
20 
21     public Integer getId() {
22         return id;
23     }
24 
25     public void setId(Integer id) {
26         this.id = id;
27     }
28 
29     public String getCont() {
30         return cont;
31     }
32 
33     public void setCont(String cont) {
34         this.cont = cont;
35     }
36 
37     public String getTopicName() {
38         return topicName;
39     }
40 
41     public void setTopicName(String topicName) {
42         this.topicName = topicName;
43     }
44 
45     public String getCategoryName() {
46         return categoryName;
47     }
48 
49     public void setCategoryName(String categoryName) {
50         this.categoryName = categoryName;
51     }
52 }

  1 package com.bjsxt.hibernate;
  2 
  3 import java.util.Date;
  4 import java.util.List;
  5 
  6 import org.hibernate.Query;
  7 import org.hibernate.Session;
  8 import org.hibernate.SessionFactory;
  9 import org.hibernate.cfg.AnnotationConfiguration;
 10 import org.hibernate.tool.hbm2ddl.SchemaExport;
 11 import org.junit.After;
 12 import org.junit.Before;
 13 import org.junit.Test;
 14 
 15 public class HibernateQLTest {
 16     private static SessionFactory sf = null;
 17     
 18     @Before
 19     public void beforeClass(){
 20 //        new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
 21         sf = new AnnotationConfiguration().configure().buildSessionFactory();
 22     }
 23     
 24     @After
 25     public void afterClass(){
 26         if(sf != null){
 27             sf.close();
 28         }
 29     }
 30     
 31     @Test
 32     public void testSave(){
 33         
 34         Session session = sf.getCurrentSession();
 35         session.beginTransaction();
 36         
 37         for(int i=0; i<10; i++){
 38             Category c = new Category();
 39             c.setName("c" + i);
 40             session.save(c);
 41         }
 42         
 43         for(int i=0; i<10; i++){
 44             Category c = new Category();
 45             c.setId(1);
 46             Topic t = new Topic();
 47             t.setCategory(c);
 48             t.setCreateDate(new Date());
 49             t.setTitle("t"+i);
 50             session.save(t);
 51         }
 52         
 53         for(int i=0; i<10; i++){
 54             Topic t = new Topic();
 55             t.setId(1);
 56             Msg m = new Msg();
 57             m.setTopic(t);
 58             m.setCont("m" + i);
 59             session.save(m);
 60         }
 61         
 62         session.getTransaction().commit();
 63     }
 64     
 65     @Test
 66     public void testHQL_01(){
 67         Session session = sf.getCurrentSession();
 68         session.beginTransaction();
 69         Query q = (Query) session.createQuery("from Category");
 70         List<Category> categories = (List<Category>)q.list();
 71         for(Category c : categories){
 72             System.out.println(c.getName());
 73         }
 74         session.getTransaction().commit();
 75     }
 76     
 77     @Test
 78     public void testHQL_02(){
 79         Session session = sf.getCurrentSession();
 80         session.beginTransaction();
 81         Query q = (Query) session.createQuery("from Category c where c.name > ‘c5‘");
 82         List<Category> categories = (List<Category>)q.list();
 83         for(Category c : categories){
 84             System.out.println(c.getName());
 85         }
 86         session.getTransaction().commit();
 87     }
 88     
 89     @Test
 90     public void testHQL_03(){
 91         Session session = sf.getCurrentSession();
 92         session.beginTransaction();
 93         Query q = (Query) session.createQuery("from Category c order by name desc");
 94         List<Category> categories = (List<Category>)q.list();
 95         for(Category c : categories){
 96             System.out.println(c.getName());
 97         }
 98         session.getTransaction().commit();
 99     }
100     
101     @Test
102     public void testHQL_04(){
103         Session session = sf.getCurrentSession();
104         session.beginTransaction();
105         Query q = (Query) session.createQuery(
106                 "select distinct c from Category c order by name desc");//主键不同
107         List<Category> categories = (List<Category>)q.list();
108         for(Category c : categories){
109             System.out.println(c.getName());
110         }
111         session.getTransaction().commit();
112     }
113     
114     @Test
115     public void testHQL_05(){
116         Session session = sf.getCurrentSession();
117         session.beginTransaction();
118         /*Query q = (Query) session.createQuery(
119                 "from Category c where c.id > :min and c.id < :max");//主键不同
120 //        q.setParameter("min", 2);
121 //        q.setParameter("max", 8);
122         q.setInteger("min", 2);
123         q.setInteger("max", 8);*/
124         
125         Query q = (Query) session.createQuery("from Category c where c.id > :min and c.id < :max")
126                 .setInteger("min", 2)
127                 .setInteger("max", 8);
128         List<Category> categories = (List<Category>)q.list();
129         for(Category c : categories){
130             System.out.println(c.getId() + "-" +c.getName());
131         }
132         session.getTransaction().commit();
133     }
134     
135     /**
136      * 链式编程
137      */
138     @Test
139     public void testHQL_06(){
140         Session session = sf.getCurrentSession();
141         session.beginTransaction();
142         Query q = (Query) session.createQuery("from Category c where c.id > ? and c.id < ?")
143                 .setInteger(0, 2)//索引从0开始
144                 .setInteger(1, 8);
145         List<Category> categories = (List<Category>)q.list();
146         for(Category c : categories){
147             System.out.println(c.getId() + "-" +c.getName());
148         }
149         session.getTransaction().commit();
150     }
151     
152     /**
153      * 分页
154      */
155     @Test
156     public void testHQL_07(){
157         Session session = sf.getCurrentSession();
158         session.beginTransaction();
159         Query q = (Query) session.createQuery("from Category c order by name desc");
160         q.setMaxResults(4);//每页4条
161         q.setFirstResult(2);//从第二行开始
162         List<Category> categories = (List<Category>)q.list();
163         for(Category c : categories){
164             System.out.println(c.getId() + "-" +c.getName());
165         }
166         session.getTransaction().commit();
167     }
168     
169     /**
170      * 分页(换一种获取方式)
171      */
172     @Test
173     public void testHQL_08(){
174         Session session = sf.getCurrentSession();
175         session.beginTransaction();
176         Query q = (Query) session.createQuery("select c.id,c.name from Category c order by name desc");
177         q.setMaxResults(4);//每页4条
178         q.setFirstResult(2);//从第二行开始
179         List<Object[]> categories = (List<Object[]>)q.list();
180         for(Object[] c : categories){
181             System.out.println(c[0] + "-" +c[1]);
182         }
183         session.getTransaction().commit();
184     }
185     
186     /**
187      * 设定 fetch type 为 lazy 后将不会有第二条sql语句
188      */
189     @Test
190     public void testHQL_09(){
191         Session session = sf.getCurrentSession();
192         session.beginTransaction();
193         Query q = session.createQuery("from Topic t where t.category.id = 1");
194         List<Topic> topics = (List<Topic>)q.list();
195         for(Topic t : topics){
196             System.out.println(t.getId() + "-" + t.getTitle());
197 //            System.out.println(t.getCategory().getName());
198         }
199         session.getTransaction().commit();
200     }
201     
202     /**
203      * 设定 fetch type 为 lazy 后将不会有第二条sql语句
204      */
205     @Test
206     public void testHQL_10(){
207         Session session = sf.getCurrentSession();
208         session.beginTransaction();
209         Query q = session.createQuery("from Topic t where t.category.id = 1");
210         List<Topic> topics = (List<Topic>)q.list();
211         for(Topic t : topics){
212             System.out.println(t.getId() + "-" + t.getTitle());
213 //            System.out.println(t.getCategory().getName());
214         }
215         session.getTransaction().commit();
216     }
217     
218     @Test
219     public void testHQL_11(){
220         Session session = sf.getCurrentSession();
221         session.beginTransaction();
222         Query q = session.createQuery("from Msg m where m.topic.category.id = 1");
223         for(Object o : q.list()){
224             Msg m = (Msg)o;
225             System.out.println(m.getCont());
226         }
227         session.getTransaction().commit();
228     }
229     
230     /**
231      * VO(Value Object)
232      * DTO(Data Transfer Object)
233      */
234     @Test
235     public void testHQL_12(){
236         Session session = sf.getCurrentSession();
237         session.beginTransaction();
238         Query q = session.createQuery("select new com.bjsxt.hibernate.MsgInfo(m.id, m.cont, m.topic.title, m.topic.category.name) from Msg m");
239         for(Object o : q.list()){
240             MsgInfo m = (MsgInfo)o;
241             System.out.println(m.getCont());
242         }
243         session.getTransaction().commit();
244     }
245     
246     //动手测试left right join
247     //为什么不能直接写 Category 名，而必须写 t.category
248     //因为有可能存在多个成员变量（同一个类），需要指明哪一个成员变量的连接条件来做连接
249     @Test
250     public void testHQL_13(){
251         Session session = sf.getCurrentSession();
252         session.beginTransaction();
253         Query q = session.createQuery("select t.title,c.name from Topic t join t.category c");
254         List<Object[]> list = q.list();
255         for(Object[] o : list){
256             System.out.println(o[0] + "-" + o[1]);
257         }
258         session.getTransaction().commit();
259     }
260     
261     //学习使用 uniqueResult
262     @Test
263     public void testHQL_14(){
264         Session session = sf.getCurrentSession();
265         session.beginTransaction();
266         Query q = session.createQuery("from Msg m where m = :MsgToSearch");//不重要
267         Msg m = new Msg();
268         m.setId(1);
269         q.setParameter("MsgToSearch", m);
270         
271         Msg mResult = (Msg)q.uniqueResult();
272         System.out.println(mResult.getCont());
273         
274         session.getTransaction().commit();
275     }
276     
277     @Test
278     public void testHQL_15(){
279         Session session = sf.getCurrentSession();
280         session.beginTransaction();
281         Query q = session.createQuery("select count(*) from Msg m");
282         
283         long count = (Long)q.uniqueResult();
284         System.out.println(count);        
285         session.getTransaction().commit();
286     }
287     
288     @Test
289     public void testHQL_16(){
290         Session session = sf.getCurrentSession();
291         session.beginTransaction();
292         Query q = session.createQuery("select max(m.id), min(m.id), avg(m.id), sum(m.id) from Msg m");
293         
294         Object[] o = (Object[])q.uniqueResult();
295         System.out.println(o[0] + "-" + o[1] + "-" + o[2] + "-" + o[3]);
296         
297         session.getTransaction().commit();
298     }
299     
300     @Test
301     public void testHQL_17(){
302         Session session = sf.getCurrentSession();
303         session.beginTransaction();
304         Query q = session.createQuery("from Msg m where m.id between 3 and 5");
305         
306         for(Object o : q.list()){
307             Msg m = (Msg)o;
308             System.out.println(m.getId() + "-" +m.getCont());
309         }
310         
311         session.getTransaction().commit();
312     }
313     
314     @Test
315     public void testHQL_18(){
316         Session session = sf.getCurrentSession();
317         session.beginTransaction();
318         Query q = session.createQuery("from Msg m where m.id in(3,4,5)");
319         
320         for(Object o : q.list()){
321             Msg m = (Msg)o;
322             System.out.println(m.getId() + "-" +m.getCont());
323         }
324         
325         session.getTransaction().commit();
326     }
327     
328     @Test
329     public void testHQL_19(){
330         Session session = sf.getCurrentSession();
331         session.beginTransaction();
332         Query q = session.createQuery("from Msg m where m.cont is not null");
333         
334         for(Object o : q.list()){
335             Msg m = (Msg)o;
336             System.out.println(m.getId() + "-" +m.getCont());
337         }
338         
339         session.getTransaction().commit();
340     }
341     
342     @Test
343     public void testSchemaExport(){
344         new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
345     }
346     
347     public static void main(String[] args) {
348 //        new HibernatTreeTest().testSave();
349         new HibernateQLTest().beforeClass();
350     }
351     
352 }

  1 package com.bjsxt.hibernate;
  2 
  3 import java.util.Date;
  4 import java.util.List;
  5 
  6 import org.hibernate.Query;
  7 import org.hibernate.SQLQuery;
  8 import org.hibernate.Session;
  9 import org.hibernate.SessionFactory;
 10 import org.hibernate.cfg.AnnotationConfiguration;
 11 import org.hibernate.tool.hbm2ddl.SchemaExport;
 12 import org.junit.After;
 13 import org.junit.Before;
 14 import org.junit.Test;
 15 
 16 public class HibernateQLTest {
 17     private static SessionFactory sf = null;
 18     
 19     @Before
 20     public void beforeClass(){
 21 //        new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
 22         sf = new AnnotationConfiguration().configure().buildSessionFactory();
 23     }
 24     
 25     @After
 26     public void afterClass(){
 27         if(sf != null){
 28             sf.close();
 29         }
 30     }
 31     
 32     @Test
 33     public void testSave(){
 34         
 35         Session session = sf.getCurrentSession();
 36         session.beginTransaction();
 37         
 38         for(int i=0; i<10; i++){
 39             Category c = new Category();
 40             c.setName("c" + i);
 41             session.save(c);
 42         }
 43         
 44         for(int i=0; i<10; i++){
 45             Category c = new Category();
 46             c.setId(1);
 47             Topic t = new Topic();
 48             t.setCategory(c);
 49             t.setCreateDate(new Date());
 50             t.setTitle("t"+i);
 51             session.save(t);
 52         }
 53         
 54         for(int i=0; i<10; i++){
 55             Topic t = new Topic();
 56             t.setId(1);
 57             Msg m = new Msg();
 58             m.setTopic(t);
 59             m.setCont("m" + i);
 60             session.save(m);
 61         }
 62         
 63         session.getTransaction().commit();
 64     }
 65     
 66     //is empty and is not empty
 67     @Test
 68     public void testHQL_20(){
 69         Session session = sf.getCurrentSession();
 70         session.beginTransaction();
 71         Query q = session.createQuery("from Topic t where t.msgs is empty");
 72         
 73         for(Object o : q.list()){
 74             Topic t = (Topic)o;
 75             System.out.println(t.getId() + "-" +t.getTitle());
 76         }
 77         
 78         session.getTransaction().commit();
 79     }
 80     
 81     @Test
 82     public void testHQL_21(){
 83         Session session = sf.getCurrentSession();
 84         session.beginTransaction();
 85         Query q = session.createQuery("from Topic t where t.title like ‘%5‘");
 86         
 87         for(Object o : q.list()){
 88             Topic t = (Topic)o;
 89             System.out.println(t.getId() + "-" +t.getTitle());
 90         }
 91         
 92         session.getTransaction().commit();
 93     }
 94     
 95     @Test
 96     public void testHQL_22(){
 97         Session session = sf.getCurrentSession();
 98         session.beginTransaction();
 99         Query q = session.createQuery("from Topic t where t.title like ‘_5‘");
100         
101         for(Object o : q.list()){
102             Topic t = (Topic)o;
103             System.out.println(t.getId() + "-" +t.getTitle());
104         }
105         
106         session.getTransaction().commit();
107     }
108     
109     //不重要
110     @Test
111     public void testHQL_23(){
112         Session session = sf.getCurrentSession();
113         session.beginTransaction();
114         Query q = session.createQuery("select lower(t.title),"
115                 + "upper(t.title),"
116                 + "trim(t.title),"
117                 + "concat(t.title,‘***‘),"
118                 + "length(t.title) "
119                 + "from Topic t");
120         
121         for(Object o : q.list()){
122             Object[] arr = (Object[])o;
123             System.out.println(arr[0] + "-" + arr[1] + "-" + arr[2] + "-" + arr[3] + "-" + arr[4]);
124         }
125         
126         session.getTransaction().commit();
127     }
128     
129     @Test
130     public void testHQL_24(){
131         Session session = sf.getCurrentSession();
132         session.beginTransaction();
133         Query q = session.createQuery("select abs(t.id),"
134                 + "sqrt(t.id),"
135                 + "mod(t.id,2) "
136                 + "from Topic t");
137         
138         for(Object o : q.list()){
139             Object[] arr = (Object[])o;
140             System.out.println(arr[0] + "-" + arr[1] + "-" + arr[2]);
141         }
142         
143         session.getTransaction().commit();
144     }
145     
146     @Test
147     public void testHQL_25(){
148         Session session = sf.getCurrentSession();
149         session.beginTransaction();
150         Query q = session.createQuery("select current_date,current_time,current_timestamp,t.id from Topic t");
151         
152         for(Object o : q.list()){
153             Object[] arr = (Object[])o;
154             System.out.println(arr[0] + "|" + arr[1] + "|" + arr[2] + "|" + arr[3]);
155         }
156         
157         session.getTransaction().commit();
158     }
159     
160     @Test
161     public void testHQL_26(){
162         Session session = sf.getCurrentSession();
163         session.beginTransaction();
164         Query q = session.createQuery("from Topic t where t.createDate < :date");
165         q.setParameter("date", new Date());
166         
167         for(Object o : q.list()){
168             Topic t = (Topic)o;
169             System.out.println(t.getTitle());
170         }
171         
172         session.getTransaction().commit();
173     }
174     
175     @Test
176     public void testHQL_27(){
177         Session session = sf.getCurrentSession();
178         session.beginTransaction();
179         Query q = session.createQuery("select t.title, count(*) from Topic t group by t.title");
180         
181         for(Object o : q.list()){
182             Object[] arr = (Object[])o;
183             System.out.println(arr[0] + "|" + arr[1]);
184         }
185         
186         session.getTransaction().commit();
187     }
188     
189     @Test
190     public void testHQL_28(){
191         Session session = sf.getCurrentSession();
192         session.beginTransaction();
193         Query q = session.createQuery("select t.title, count(*) from Topic t group by t.title having count(*) > 0");
194         
195         for(Object o : q.list()){
196             Object[] arr = (Object[])o;
197             System.out.println(arr[0] + "|" + arr[1]);
198         }
199         
200         session.getTransaction().commit();
201     }
202     
203     @Test
204     public void testHQL_29(){
205         Session session = sf.getCurrentSession();
206         session.beginTransaction();
207         Query q = session.createQuery("from Topic t where t.id < (select avg(t.id) from Topic t)");
208         
209         for(Object o : q.list()){
210             Topic t = (Topic)o;
211             System.out.println(t.getTitle());
212         }
213         
214         session.getTransaction().commit();
215     }
216     
217     @Test
218     public void testHQL_30(){
219         Session session = sf.getCurrentSession();
220         session.beginTransaction();
221         Query q = session.createQuery("from Topic t where t.id < ALL (select t.id from Topic t where mod(t.id,2) = 0)");
222         
223         for(Object o : q.list()){
224             Topic t = (Topic)o;
225             System.out.println(t.getTitle());
226         }
227         
228         session.getTransaction().commit();
229     }
230     
231     //用in可以实现 exists 的功能
232     //但是 exists 执行效率高
233     @Test
234     public void testHQL_31(){
235         Session session = sf.getCurrentSession();
236         session.beginTransaction();
237         Query q = session.createQuery("from Topic t where not exists (select m.id from Msg m where m.topic.id = t.id)");//就是沒有回帖的topic
238         
239         for(Object o : q.list()){
240             Topic t = (Topic)o;
241             System.out.println(t.getTitle());
242         }
243         
244         session.getTransaction().commit();
245     }
246     
247     @Test
248     public void testHQL_32(){
249         Session session = sf.getCurrentSession();
250         session.beginTransaction();
251         
252         Query q = session.createQuery("update Topic t set t.title = upper(t.title)");
253         q.executeUpdate();
254         q = session.createQuery("from Topic");
255         for(Object o : q.list()){
256             Topic t = (Topic)o;
257             System.out.println(t.getTitle());
258         }
259         
260         q = session.createQuery("update Topic t set t.title = lower(t.title)");
261         q.executeUpdate();
262         
263         session.getTransaction().commit();
264     }
265     
266     //不重要
267     @Test
268     public void testHQL_33(){
269         Session session = sf.getCurrentSession();
270         session.beginTransaction();
271         
272         Query q = session.getNamedQuery("topic.selectCertainTopic");
273         q.setParameter("id", 5);
274         Topic t = (Topic)q.uniqueResult();
275         System.out.println(t.getTitle());
276         
277         session.getTransaction().commit();
278     }
279     
280     //Native(不太重要)
281     @Test
282     public void testHQL_34(){
283         Session session = sf.getCurrentSession();
284         session.beginTransaction();
285         
286         SQLQuery q = session.createSQLQuery("select * from category limit 2,4").addEntity(Category.class);
287         List<Category> categories = (List<Category>)q.list();
288         for(Category c : categories){
289             System.out.println(c.getName());
290         }
291         
292         session.getTransaction().commit();
293     }
294     
295     @Test
296     public void testSchemaExport(){
297         new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
298     }
299     
300     public static void main(String[] args) {
301 //        new HibernatTreeTest().testSave();
302         new HibernateQLTest().beforeClass();
303     }
304     
305 }