Hibernate学习（五）---【一对多单项】

Classes和Student一对多。要站在classes这段来看。
classes.java

package com.zzn.hibernate.oneToMany;

import java.util.Set;

public class Classes {
    private int id;
    private String name;
    private Set students;

    public Set getStudents() {
        return students;
    }
    public void setStudents(Set students) {
        this.students = students;
    }
    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;
    }


}

Student.java

package com.zzn.hibernate.oneToMany;

public class Student {

private int id;

private String name;

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;

}

Class.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.zzn.hibernate.oneToMany">
    <class name="Classes" table="CLASSES">
        <id name="id" column="id">
            <generator class="native" />
        </id>
        <property name="name" />
        
        <set name="students" cascade="all">
            
            <key column="classesid"/>
            <one-to-many class="Student"/>
        </set>
    </class>
</hibernate-mapping>

Student.hbm.xml

test.java

package com.zzn.hibernate;

import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import junit.framework.TestCase;

import org.hibernate.Session;
import org.hibernate.Transaction;

import com.zzn.hibernate.hibernateUtil.HibernateUtils;
import com.zzn.hibernate.oneToMany.Classes;
import com.zzn.hibernate.oneToMany.Student;

public class OneToManyTest extends TestCase {

    @SuppressWarnings("unchecked")
    public void OneToManySave() {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();

            Student student1 = new Student();
            student1.setName("刘德华");
            Student student2 = new Student();
            student2.setName("周杰伦");

            Set students = new HashSet();
            students.add(student1);
            students.add(student2);

            Classes classes = new Classes();
            classes.setName("中国");
            classes.setStudents(students);

            session.save(classes);

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (session != null) {
                if (session.isOpen()) {
                    tx.commit();
                    session.close();
                }
            }
        }
    }

    @SuppressWarnings("unchecked")
    public void OneToManyLoad() {
        Session session = null;
        Transaction tx = null;
        try {
            session = HibernateUtils.getSession();
            tx = session.beginTransaction();
            Classes classes = (Classes)session.load(Classes.class, 1);
            Set students = classes.getStudents();
            for (Iterator iter=students.iterator(); iter.hasNext();){
                Student student = (Student)iter.next();
                System.out.println("student.name="+student.getName());
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (session != null) {
                if (session.isOpen()) {
                    tx.commit();
                    session.close();
                }
            }
        }
    }
}

posted on 2009-11-01 16:01 生命的绽放阅读(459) 评论(0) 编辑收藏所属分类: Hibernate

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