hi, i got 2 entities, Student and Phone, and a relationship one-to-many between them.
Code:
@Entity
@Table(name = "STUDENT")
public class Student {
private long studentId;
private String studentName;
private Set<Phone> studentPhoneNumbers = new HashSet<Phone>(0);
public Student() {
}
public Student(String studentName, Set<Phone> studentPhoneNumbers) {
this.studentName = studentName;
this.studentPhoneNumbers = studentPhoneNumbers;
}
@Id
@GeneratedValue
@Column(name = "STUDENT_ID")
public long getStudentId() {
return this.studentId;
}
public void setStudentId(long studentId) {
this.studentId = studentId;
}
@Column(name = "STUDENT_NAME", nullable = false, length = 100)
public String getStudentName() {
return this.studentName;
}
public void setStudentName(String studentName) {
this.studentName = studentName;
}
@OneToMany (mappedBy="student", cascade = CascadeType.ALL)
public Set<Phone> getStudentPhoneNumbers() {
return this.studentPhoneNumbers;
}
public void setStudentPhoneNumbers(Set<Phone> studentPhoneNumbers) {
this.studentPhoneNumbers = studentPhoneNumbers;
}
}
Code:
@Entity
@Table(name = "PHONE")
public class Phone {
private long phoneId;
private String phoneType;
private String phoneNumber;
private Student student;
private Set<Student> students = new HashSet<Student>(0);
public Phone() {
}
public Phone(String phoneType, String phoneNumber) {
this.phoneType = phoneType;
this.phoneNumber = phoneNumber;
}
@Id
@GeneratedValue
@Column(name = "PHONE_ID")
public long getPhoneId() {
return this.phoneId;
}
public void setPhoneId(long phoneId) {
this.phoneId = phoneId;
}
@Column(name = "PHONE_TYPE", nullable = false, length=10)
public String getPhoneType() {
return this.phoneType;
}
public void setPhoneType(String phoneType) {
this.phoneType = phoneType;
}
@Column(name = "PHONE_NUMBER", nullable = false, length=15)
public String getPhoneNumber() {
return this.phoneNumber;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn (name="STUDENT_ID")
public Student getStudent() {
return this.student;
}
public void setStudent(Student student) {
this.student = student;
}
here is the code of applicationContext.xml:
Code:
...
<bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost/Project"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</bean>
<bean id="mySessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="myDataSource" />
<property name="annotatedClasses">
<list>
<value>com.domain.Student</value>
<value>com.domain.Phone</value>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.HSQLDialect</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.hbm2ddl.auto">create</prop>
</props>
</property>
</bean>
<bean id="myClassDAO" class="com.project.dao.ClassDAOImpl">
<property name="sessionFactory" ref="mySessionFactory"/>
</bean>
...
And my ClassDAOImpl looks like:
Code:
public class ClassDAOImpl{
private HibernateTemplate hibernateTemplate;
private Session session;
public void setSessionFactory(SessionFactory sessionFactory) {
this.hibernateTemplate = new HibernateTemplate(sessionFactory);
this.session = sessionFactory.openSession();
}
public void updateStudent(){
Transaction transaction = session.beginTransaction();
Student s = (Student)session.get(Student.class, new Long(1));
Set<Phone> phoneNumbers =s.getStudentPhoneNumbers();
phoneNumbers.add(new Phone ("house","12342342"));
s.setStudentPhoneNumbers(phoneNumbers);
session.update(s);
transaction.commit();
}
}
I just want to add a phone to the student with primary key "1". For this purpose, first I get the student and then I update the phone set by adding a new one. Finally I update the entity Student.
I looked at my Phone table, and there was a new row with the new phone, but the foreign key (STUDENT_ID) appeared with "Null" value, therefore the relationship is not registered. How could i fix it?
Thanks in advance
Edit: I've already solved the issue, just adding this line of code
Code:
phone.setStudent(s);
What i'm wondering now, is if i'm getting the session and managing transactions properly. I've noticed that if I close the session after commit the transaction i can only execute the method updateStudent once, the second time i do, hibernate says that the connection is closed. Please, tell me if my code is correct.
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