আমি আমার প্রকল্পের সমস্ত সিআরইউডি অপারেশনের জন্য হাইবারনেট ব্যবহার করছি। এটি ওয়ান-টু-ম্যান এবং বহু-এক-এক সম্পর্কের জন্য কাজ করে না। এটি আমাকে নীচের ত্রুটি দেয়।
org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for columns: [org.hibernate.mapping.Column(students)]
তারপরে আবার আমি এই ভিডিও টিউটোরিয়ালটি দিয়েছিলাম । এটা আমার কাছে খুব সহজ, প্রথমদিকে। তবে, আমি এটি কাজ করতে পারি না। এটি এখন, বলছে
org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for columns: [org.hibernate.mapping.Column(students)]
আমি ইন্টারনেটে কিছু অনুসন্ধান চালিয়েছি , সেখানে কেউ এটি হাইবারনেটে একটি বাগ বলছে , এবং কেউ বলেছেন, @ জেনারেটেডভ্যালু যুক্ত করে এই ত্রুটিটি সাফ হয়ে যাবে, তবে এটি আমার কাজ করে না।
কলেজ.জভা
@Entity
public class College {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int collegeId;
private String collegeName;
private List<Student> students;
@OneToMany(targetEntity=Student.class, mappedBy="college", fetch=FetchType.EAGER)
public List<Student> getStudents() {
return students;
}
public void setStudents(List<Student> students) {
this.students = students;
}//Other gettters & setters omitted
ছাত্র.জভা
@Entity
public class Student {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private int studentId;
private String studentName;
private College college;
@ManyToOne
@JoinColumn(name="collegeId")
public College getCollege() {
return college;
}
public void setCollege(College college) {
this.college = college;
}//Other gettters & setters omitted
মাইন.জভা:
public class Main {
private static org.hibernate.SessionFactory sessionFactory;
public static SessionFactory getSessionFactory() {
if (sessionFactory == null) {
initSessionFactory();
}
return sessionFactory;
}
private static synchronized void initSessionFactory() {
sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
}
public static Session getSession() {
return getSessionFactory().openSession();
}
public static void main (String[] args) {
Session session = getSession();
Transaction transaction = session.beginTransaction();
College college = new College();
college.setCollegeName("Dr.MCET");
Student student1 = new Student();
student1.setStudentName("Peter");
Student student2 = new Student();
student2.setStudentName("John");
student1.setCollege(college);
student2.setCollege(college);
session.save(student1);
session.save(student2);
transaction.commit();
}
}
কনসোল:
Exception in thread "main" org.hibernate.MappingException: Could not determine type for: java.util.List, at table: College, for columns: [org.hibernate.mapping.Column(students)]
at org.hibernate.mapping.SimpleValue.getType(SimpleValue.java:306)
at org.hibernate.mapping.SimpleValue.isValid(SimpleValue.java:290)
at org.hibernate.mapping.Property.isValid(Property.java:217)
at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:463)
at org.hibernate.mapping.RootClass.validate(RootClass.java:235)
at org.hibernate.cfg.Configuration.validate(Configuration.java:1330)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1833)
at test.hibernate.Main.initSessionFactory(Main.java:22)
at test.hibernate.Main.getSessionFactory(Main.java:16)
at test.hibernate.Main.getSession(Main.java:27)
at test.hibernate.Main.main(Main.java:43)
এক্সএমএল:
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/dummy</property>
<property name="connection.username">root</property>
<property name="connection.password">1234</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<mapping class="test.hibernate.Student" />
<mapping class="test.hibernate.College" />
</session-factory>