[原]联合外键作主键 @EmbeddwdId

嵌入类:

package com.dlnu.model;

import java.io.Serializable;

import javax.persistence.Embeddable;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
@Embeddable
public class Name implements Serializable {

    private static final long serialVersionUID = 1L;

    private Course course;

    private Student student;

    public Name() {
    }

    public Name(Course course, Student student) {
        this.course = course;
        this.student = student;

    }

    @ManyToOne
    @JoinColumn(name = "courseId", referencedColumnName = "cno",nullable=true)
    public Course getCourse() {
        return course;
    }
    @ManyToOne
    @JoinColumn(name = "studentId", referencedColumnName = "sno")
    public Student getStudent() {
        return student;
    }

    public void setStudent(Student student) {
        this.student = student;
    }

    public void setCourse(Course course) {
        this.course = course;
    }

    public boolean equals(Object obj) {

        if (this == obj) {
            return true;
        }
        if (obj.getClass() == Name.class) {
            Name target = (Name) obj;
            if (target.getCourse().equals(course)
                    && target.getStudent().equals(student)) {
                return true;
            }
        }
        return false;
    }

    public int hashCode() {

        return course.hashCode() + student.hashCode() * 17;
    }

}

 

实体类:

package com.dlnu.model;

import javax.persistence.EmbeddedId;
import javax.persistence.Entity;

@Entity
public class SC {


    private Name name;

    private Double grade;

    public Double getGrade() {
        return grade;
    }

    @EmbeddedId
    public Name getName() {
        return name;
    }
    public void setGrade(Double grade) {
        this.grade = grade;
    }
    public void setName(Name name) {
        this.name = name;
    }

}

作者：chengchanglun 发表于2012-4-9 14:59:58 原文链接

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