学生选课系统设计-优快云博客

本文介绍了一个基于Hibernate的学生选课系统的实现方案，包括学生、课程及选课记录等实体类的设计，以及通过第三方表实现多对多关系的具体配置。

多对多
案列学生选课
domain

package com.hsp.domain;

import java.util.Set;

public class Student {
    private Integer id;
    private String name;
    private Set<StuCourse> stuCourses;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Set<StuCourse> getStuCourses() {
        return stuCourses;
    }
    public void setStuCourses(Set<StuCourse> stuCourses) {
        this.stuCourses = stuCourses;
    }
}

package com.hsp.domain;

import java.util.Set;

public class Course {
    private Integer id;
    private String name;
    private Set<StuCourse> stuCourses;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Set<StuCourse> getStuCourses() {
        return stuCourses;
    }
    public void setStuCourses(Set<StuCourse> stuCourses) {
        this.stuCourses = stuCourses;
    }
}

第三方表

package com.hsp.domain;

public class StuCourse {
    private Integer id;
    private Student student;
    private Course course;
    private Integer grade;
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public Student getStudent() {
        return student;
    }
    public void setStudent(Student student) {
        this.student = student;
    }
    public Course getCourse() {
        return course;
    }
    public void setCourse(Course course) {
        this.course = course;
    }
    public Integer getGrade() {
        return grade;
    }
    public void setGrade(Integer grade) {
        this.grade = grade;
    }
}

配置文件

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.hsp.domain">
<class name="Student">
<id name="id" type="java.lang.Integer">
<generator class="sequence">
<param name="sequence">stu_seq</param>
</generator>
</id>
<property name="name" type="java.lang.String">
<column name="name" length="64"/>
</property>
<!-- 这里我们配置了one-to-many 一个学生可以对应多个选课记录 -->
<set name="stuCourses">
<key column="student_id"/>
<one-to-many class="StuCourse"/>
</set>
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.hsp.domain">
<class name="Course">
<id name="id" type="java.lang.Integer">
<generator class="sequence">
<param name="sequence">course_seq</param>
</generator>
</id>
<property name="name" type="java.lang.String">
<column name="name" length="64"/>
</property>
<!-- 配置one-to-many 表示一门课程可以对应多个选课记录 -->
<set name="stuCourses">
<key column="course_id"/>
<one-to-many class="StuCourse"/>
</set>
</class>
</hibernate-mapping>

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.hsp.domain">
<class name="StuCourse" >
<id name="id" type="java.lang.Integer">
<generator class="sequence">
<param name="sequence">stucourse_seq</param>
</generator>
</id>
<property name="grade" type="java.lang.Integer">
<column name="grade" length="3"/>
</property>
<many-to-one name="course" column="course_id"/>
<many-to-one name="student" column="student_id"/>
</class>
</hibernate-mapping>

测试

package com.hsp.view;

import java.util.Date;
import java.util.HashSet;
import java.util.Set;

import org.hibernate.Hibernate;
import org.hibernate.Session;
import org.hibernate.Transaction;
import com.hsp.domain.Course;
import com.hsp.domain.StuCourse;
import com.hsp.domain.Student;
import com.hsp.util.HibernateUtil;

public class TestMain {

    /**
     * @param args
     */
    public static void main(String[] args) {

        //添加一组Person/idcard

        Session s=null;
        Transaction tx=null;

        try {
            //我们使用基础模板来讲解.
            s=HibernateUtil.getCurrentSession();
            tx=s.beginTransaction();

            //添加一个学生，一门课程，选课
            Student stu1=new Student();
            stu1.setName("小明");

            Course course=new Course();
            course.setName("java");

            StuCourse sc=new StuCourse();

            sc.setCourse(course);
            sc.setStudent(stu1);

            //顺序保存.
            s.save(stu1);
            s.save(course);
            s.save(sc);

            tx.commit();

        } catch (Exception e) {
            e.printStackTrace();
            if(tx!=null){
                tx.rollback();
            }
        }finally{

            if(s!=null && s.isOpen()){
                s.close();
            }
        }       

    }   

}

Hibernate多对多