关于hibernate一个很简单的manytoone的问题 看不出错在哪 能帮个忙么

Question

查了下资料
很多人说是@Entity没加  可我加了啊
package com.model;import java.util.ArrayList;
import java.util.List;import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;@Entity
public class Classes {
private int id;
private List<Student> student = new ArrayList<Student>(); @OneToMany(mappedBy = "clas", cascade = { CascadeType.ALL })
public List<Student> getStudent() {
return student;
} public void setStudent(List<Student> student) {
this.student = student;
} @Id
@GeneratedValue
public int getId() {
return id;
} public void setId(int id) {
this.id = id;
}
}
package com.model;import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToOne;@Entity
public class Student {
private int id;
private String name;
private String age;
private Classes clas;
@Id
@GeneratedValue
public int getId() {
return id;
} public void setId(int id) {
this.id = id;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public String getAge() {
return age;
} public void setAge(String age) {
this.age = age;
}

@ManyToOne(cascade = { CascadeType.ALL })

public Classes getClas() {
return clas;
} public void setClas(Classes clas) {
this.clas = clas;
}}
package com;import java.util.List;import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;import com.model.Classes;
import com.model.Student;public class Main { /**
 * @param args
 */
public static void main(String[] args) {
Student s= new Student();
Classes c = new Classes();
s.setClas(c);
System.out.println(s.getId()+"1");
// TODO Auto-generated method stub
SessionFactory sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
Session session = sessionFactory.getCurrentSession();
session.beginTransaction();
session.save(s);
session.save(c);
System.out.println(s.getId()+"2");
session.getTransaction().commit();
System.out.println(s.getId()+"4");
}}
二月 12, 2013 10:49:20 下午 org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final}
二月 12, 2013 10:49:20 下午 org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.1.4.Final}
二月 12, 2013 10:49:20 下午 org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
二月 12, 2013 10:49:20 下午 org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
二月 12, 2013 10:49:20 下午 org.hibernate.cfg.Configuration configure
INFO: HHH000043: Configuring from resource: /hibernate.cfg.xml
二月 12, 2013 10:49:20 下午 org.hibernate.cfg.Configuration getConfigurationInputStream
INFO: HHH000040: Configuration resource: /hibernate.cfg.xml
二月 12, 2013 10:49:21 下午 org.hibernate.cfg.Configuration doConfigure
INFO: HHH000041: Configured SessionFactory: null
Exception in thread "main" org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.model.Student.clas references an unknown entity: com.model.Classes
at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:109)
at org.hibernate.cfg.Configuration.processEndOfQueue(Configuration.java:1519)
at org.hibernate.cfg.Configuration.processFkSecondPassInOrder(Configuration.java:1444)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1362)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1731)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1782)
at com.Main.main(Main.java:25)

Answer 1

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<!-- Generated by MyEclipse Hibernate Tools. -->
<hibernate-configuration> <session-factory>
<property name="connection.url">
jdbc:sqlserver://localhost:1433;databaseName=hu;
</property>
<property name="connection.username">hu</property>
<property name="connection.password">xk53fdab</property>
<property name="connection.driver_class">
com.microsoft.sqlserver.jdbc.SQLServerDriver
</property>
<property name="dialect">
org.hibernate.dialect.SQLServerDialect
</property>
<property name="current_session_context_class">thread</property>
<property name="show_sqlserver">true</property>
<property name="hbm2ddl.auto">update</property>
<mapping class="com.model.Student"></mapping>
</session-factory></hibernate-configuration>

Answer 2

配置文件错了，少了<mapping class="com.model.Classes"></mapping>