Hibernate 一对多单向关联Demo
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时间：2015年06月09日
以Classes[班级]和Student[学生]为例的Demo
Classes .java public class Classes implements Serializable { private long Cid; private String Cname; private String Cdesc; private Set<Student> students; //get和set }
Student .java public class Student implements Serializable { private long Sid; private String Sname; private String Sdesc; //get和set }
映射文件：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> 4 <hibernate-mapping> 5 <class name="cn.test.test.Classes" table="classes"> 6 <id name="Cid" type="java.lang.Long" length="5"> 7 <column name="Cid"></column> 8 <generator class="increment"></generator> 9 </id> 10 <property name="Cname" type="java.lang.String" length="20"></property> 11 <property name="Cdesc" type="java.lang.String" length="50"></property> 12 13 <!-- 14 set元素和类中的set集合对应 15 * 从外键的角度建立classes与student之间的关系 16 * 从类与类的角度建立classes与student之间的关系 17 cascade级联 18 inverse是用来维护关系的 19 * 要么是一对多的关系 20 * 要么多对多的关系 21 * 谁来维护关系 22 inverse所在的映射文件对应的持久化对象维护关系 23 默认值是false 表明维护关系 24 true 表明不维护关系 25 --> 26 <set name="students" cascade="all"> 27 <!-- 28 key是用来描述外键 29 column就代表外键的名字 30 --> 31 <key> 32 <column name="Cid"></column> 33 </key> 34 <!-- 35 classes和哪个对象进行关联 36 --> 37 <one-to-many class="cn.test.test.Student"/> 38 </set> 39 40 </class> 41 </hibernate-mapping>
1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" 3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> 4 <hibernate-mapping> 5 <class name="cn.test.test.Student" table="student"> 6 <id name="Sid" type="java.lang.Long" length="5"> 7 <column name="Sid"></column> 8 <generator class="increment"></generator> 9 </id> 10 <property name="Sname" type="java.lang.String" length="20"></property> 11 <property name="Sdesc" type="java.lang.String" length="50"></property> 12 </class> 13 </hibernate-mapping>
1 package cn.test.test; 2 3 import java.util.HashSet; 4 import java.util.List; 5 import java.util.Set; 6 7 import javax.crypto.interfaces.PBEKey; 8 9 import org.hibernate.Session; 10 import org.hibernate.SessionFactory; 11 import org.hibernate.Transaction; 12 import org.hibernate.cfg.Configuration; 13 import org.junit.Test; 14 15 public class DoTest { 16 /** 17 * 1、保存班级 18 * 2、保存学生 19 * 3、保存班级的时候同时保存学生 20 * 4、保存班级的时候同时保存学生，并且建立班级和学生之间的关系 21 * 5、已经存在一个班级，新建一个学生，并且建立该学生和该班级之间的关系 22 * 6、已经存在一个学生，新建一个班级，并且建立该学生和该班级之间的关系 23 * 7、已经存在一个学生，已经存在一个班级，解除该学生和原来班级之间的关系，建立该学生和新班级之间的关系 24 * 8、已经存在一个学生，解除该学生和该学生所在班级之间的关系 25 * 9、解除该班级和所有的学生之间的关系，再重新建立该班级和一些新的学员之间的关系 26 * 10、解除该班级和所有的学生之间的关系 27 * 11、删除班级 28 * * 29 * * 解除该班级和所有的学生之间的关系 30 * * 删除该班级 31 * * 32 * 删除班级的同时删除学生 33 * 12、删除学生 34 * 同删除班级 35 */ 36 37 private static SessionFactory sessionFactory; 38 static{ 39 Configuration configuration=new Configuration(); 40 configuration.configure(); 41 sessionFactory=configuration.buildSessionFactory(); 42 } 43 44 //1、保存班级 45 @Test 46 public void testSaveClasses(){ 47 Session session=sessionFactory.openSession(); 48 Transaction transaction= session.beginTransaction(); 49 Classes classes=new Classes(); 50 classes.setCname("Tom"); 51 classes.setCdesc("1234567890-"); 52 session.save(classes); 53 transaction.commit(); 54 session.close(); 55 } 56 //2、保存学生 57 @Test 58 public void testSaveStudents(){ 59 Session session=sessionFactory.openSession(); 60 Transaction transaction= session.beginTransaction(); 61 Student student=new Student(); 62 student.setSname("屌丝班"); 63 student.setSdesc("都是纯逗比纯屌丝"); 64 session.save(student); 65 transaction.commit(); 66 session.close(); 67 } 68 //3、保存班级的时候同时保存学生 69 /* 70 * Hibernate: select max(Sid) from student 71 Hibernate: select max(Cid) from classes 72 Hibernate: insert into student (Sname, Sdesc, Sid) values (?, ?, ?) 73 Hibernate: insert into classes (Cname, Cdesc, Cid) values (?, ?, ?) 74 */ 75 @Test 76 public void testSaveClasses_Students(){ 77 Session session=sessionFactory.openSession(); 78 Transaction transaction= session.beginTransaction(); 79 80 Student student=new Student(); 81 student.setSname("屌丝班"); 82 student.setSdesc("都是纯逗比纯屌丝"); 83 session.save(student); 84 85 Classes classes=new Classes(); 86 classes.setCname("Tom"); 87 classes.setCdesc("1234567890-"); 88 session.save(classes); 89 90 transaction.commit(); 91 session.close(); 92 } 93 94 //4、保存班级的时候同时保存学生，并且建立班级和学生之间的关系 95 /*classes.hbm.xml中设置;<set name="students" cascade="save-update"> 96 * Hibernate: select max(Cid) from classes 97 Hibernate: select max(Sid) from student 98 Hibernate: insert into classes (Cname, Cdesc, Cid) values (?, ?, ?) 99 Hibernate: insert into student (Sname, Sdesc, Sid) values (?, ?, ?) 100 Hibernate: update student set Cid=? where Sid=? 101 102 保存班级的时候同时保存学生，并且建立班级和学生之间的关系 103 * 在classes.hbm.xml文件中 104 * <set name="students" cascade="save-update"> 105 * inverse的值为默认或者false,才能让classes维护student的关系 106 设置<set name="students" cascade="save-update" inverse="true"> 107 Hibernate: select max(Cid) from classes 108 Hibernate: select max(Sid) from student 109 Hibernate: insert into classes (Cname, Cdesc, Cid) values (?, ?, ?) 110 Hibernate: insert into student (Sname, Sdesc, Sid) values (?, ?, ?) 111 不建立关联 112 */ 113 @Test 114 public void testSaveClasses_R_Students(){ 115 Session session=sessionFactory.openSession(); 116 Transaction transaction= session.beginTransaction(); 117 118 Student student=new Student(); 119 student.setSname("Tom"); 120 student.setSdesc("1234567890-"); 121 122 //session.save(student);必须删除掉 123 124 Set<Student> students=new HashSet<Student>(); 125 students.add(student); 126 127 Classes classes=new Classes(); 128 classes.setCname("屌丝班"); 129 classes.setCdesc("都是纯逗比纯屌丝"); 130 131 classes.setStudents(students); 132 133 session.save(classes); 134 135 transaction.commit(); 136 session.close(); 137 } 138 139 140 //5、已经存在一个班级，新建一个学生，并且建立该学生和该班级之间的关系 141 /** 142 * Hibernate: select classes0_.Cid as Cid1_0_, classes0_.Cname as Cname1_0_, classes0_.Cdesc as Cdesc1_0_ from classes classes0_ where classes0_.Cid=? 143 Hibernate: select students0_.Cid as Cid1_1_, students0_.Sid as Sid1_, students0_.Sid as Sid0_0_, students0_.Sname as Sname0_0_, students0_.Sdesc as Sdesc0_0_ from student students0_ where students0_.Cid=? 144 Hibernate: select max(Sid) from student 145 Hibernate: insert into student (Sname, Sdesc, Sid) values (?, ?, ?) 146 Hibernate: update student set Cid=? where Sid=? 147 */ 148 @Test 149 public void testSaveClassesAndStudents_R(){ 150 Session session=sessionFactory.openSession(); 151 Transaction transaction=session.beginTransaction(); 152 Classes classes=(Classes) session.get(Classes.class, 1L); 153 Student student=new Student(); 154 student.setSname("Lucy"); 155 student.setSdesc("qwertyuiop"); 156 Set<Student> set=new HashSet<Student>(); 157 //建立关系 158 classes.getStudents().add(student); 159 160 //classes.setStudents(set); 把班级中的学生重新更新了 161 162 transaction.commit(); 163 session.close(); 164 } 165 //6、已经存在一个学生，新建一个班级，并且建立该学生和该班级之间的关系 166 /* 167 * Hibernate: select student0_.Sid as Sid0_0_, student0_.Sname as Sname0_0_, student0_.Sdesc as Sdesc0_0_ from student student0_ where student0_.Sid=? 168 Hibernate: select max(Cid) from classes 169 Hibernate: insert into classes (Cname, Cdesc, Cid) values (?, ?, ?) 170 Hibernate: update student set Cid=? where Sid=? 171 */ 172 @Test 173 public void testSaveStudentAndClasses_R(){ 174 Session session =sessionFactory.openSession(); 175 Transaction transaction= session.beginTransaction(); 176 177 Student student=(Student) session.get(Student.class, 2L); 178 179 Classes classes=new Classes(); 180 classes.setCname("文艺青年班"); 181 classes.setCdesc("感觉都是文艺青年棒棒哒"); 182 183 Set<Student> set=new HashSet<Student>(); 184 set.add(student); 185 classes.setStudents(set); 186 187 session.save(classes); 188 189 transaction.commit(); 190 session.close(); 191 } 192 193 //7、已经存在一个学生，已经存在一个班级，解除该学生和原来班级之间的关系，建立该学生和新班级之间的关系 194 /* 195 * Hibernate: select student0_.Sid as Sid0_0_, student0_.Sname as Sname0_0_, student0_.Sdesc as Sdesc0_0_ from student student0_ where student0_.Sid=? 196 Hibernate: select classes0_.Cid as Cid1_0_, classes0_.Cname as Cname1_0_, classes0_.Cdesc as Cdesc1_0_ from classes classes0_ where classes0_.Cid=? 197 Hibernate: select students0_.Cid as Cid1_1_, students0_.Sid as Sid1_, students0_.Sid as Sid0_0_, students0_.Sname as Sname0_0_, students0_.Sdesc as Sdesc0_0_ from student students0_ where students0_.Cid=? 198 Hibernate: update student set Cid=? where Sid=?//建立关系 199 * 200 */ 201 @Test 202 public void testSaveRemove_Student_Classes(){ 203 Session session=sessionFactory.openSession(); 204 Transaction transaction=session.beginTransaction(); 205 Student student=(Student) session.get(Student.class, 2L); 206 207 Classes classes=(Classes) session.get(Classes.class, 1L); 208 classes.getStudents().add(student);//建立关系，没有必要删除与原来班级的关系，建立关系之后，自动解除与原来班级的关系 209 transaction.commit(); 210 session.close(); 211 } 212 //8、已经存在一个学生，解除该学生和该学生所在班级之间的关系 213 /* 214 * Hibernate: select student0_.Sid as Sid0_0_, student0_.Sname as Sname0_0_, student0_.Sdesc as Sdesc0_0_ from student student0_ where student0_.Sid=? 215 Hibernate: select classes0_.Cid as Cid1_0_, classes0_.Cname as Cname1_0_, classes0_.Cdesc as Cdesc1_0_ from classes classes0_ where classes0_.Cid=? 216 Hibernate: select students0_.Cid as Cid1_1_, students0_.Sid as Sid1_, students0_.Sid as Sid0_0_, students0_.Sname as Sname0_0_, students0_.Sdesc as Sdesc0_0_ from student students0_ where students0_.Cid=? 217 Hibernate: update student set Cid=null where Cid=? and Sid=? 218 * 219 */ 220 @Test 221 public void testRemoveStudent(){ 222 Session session=sessionFactory.openSession(); 223 Transaction transaction =session.beginTransaction(); 224 225 Student student=(Student) session.get(Student.class, 1L); 226 Classes classes=(Classes)session.get(Classes.class, 1L); 227 classes.getStudents().remove(student); 228 transaction.commit(); 229 session.close(); 230 } 231 232 //9、解除该班级和所有的学生之间的关系，再重新建立该班级和一些新的学员之间的关系 233 /* 234 * Hibernate: select classes0_.Cid as Cid1_0_, classes0_.Cname as Cname1_0_, classes0_.Cdesc as Cdesc1_0_ from classes classes0_ where classes0_.Cid=? 235 Hibernate: select student0_.Sid as Sid0_, student0_.Sname as Sname0_, student0_.Sdesc as Sdesc0_ from student student0_ where student0_.Sid in (3 , 4 , 5) 236 Hibernate: update student set Cid=null where Cid=? 237 Hibernate: update student set Cid=? where Sid=? 238 Hibernate: update student set Cid=? where Sid=? 239 Hibernate: update student set Cid=? where Sid=? 240 * 241 */ 242 @Test 243 public void testRemoveAllAndAddSome(){ 244 Session session =sessionFactory.openSession(); 245 Transaction transaction= session.beginTransaction(); 246 247 Classes classes=(Classes) session.get(Classes.class, 1L); 248 List<Student> students= session.createQuery("FROM Student WHERE Sid IN(3,4,5) ").list(); 249 250 Set<Student> sets=new HashSet<Student>(students); 251 classes.setStudents(sets); 252 253 transaction.commit(); 254 session.close(); 255 } 256 257 //10、解除该班级和所有的学生之间的关系 258 /* 259 * Hibernate: select classes0_.Cid as Cid1_0_, classes0_.Cname as Cname1_0_, classes0_.Cdesc as Cdesc1_0_ from classes classes0_ where classes0_.Cid=? 260 Hibernate: update student set Cid=null where Cid=? 261 */ 262 @Test 263 public void testRemoveAll(){ 264 Session session=sessionFactory.openSession(); 265 Transaction transaction =session.beginTransaction(); 266 267 Classes classes=(Classes) session.get(Classes.class, 1L); 268 classes.setStudents(null); 269 270 transaction.commit(); 271 session.close(); 272 } 273 /* 274 * 11、删除班级 275 * * 276 * * 解除该班级和所有的学生之间的关系 277 * * 删除该班级 278 * * 279 * 删除班级的同时删除学生 280 * 12、删除学生 281 * 同删除班级 282 * 283 */ 284 //11、删除学生,同删除班级 285 /* 286 * Hibernate: select classes0_.Cid as Cid1_0_, classes0_.Cname as Cname1_0_, classes0_.Cdesc as Cdesc1_0_ from classes classes0_ where classes0_.Cid=? 287 Hibernate: select students0_.Cid as Cid1_1_, students0_.Sid as Sid1_, students0_.Sid as Sid0_0_, students0_.Sname as Sname0_0_, students0_.Sdesc as Sdesc0_0_ from student students0_ where students0_.Cid=? 288 Hibernate: update student set Cid=null where Cid=? 289 Hibernate: delete from student where Sid=? 290 Hibernate: delete from student where Sid=? 291 Hibernate: delete from student where Sid=? 292 Hibernate: delete from classes where Cid=? 293 */ 294 @Test 295 public void testDeleteClasses(){ 296 Session session =sessionFactory.openSession(); 297 Transaction transaction=session.beginTransaction(); 298 299 Classes classes=(Classes) session.get(Classes.class, 1L); 300 session.delete(classes); 301 302 transaction.commit(); 303 session.close(); 304 } 305 }
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