classes.java

有关EJB3的实体BEAN的一对多关系的实例

package OneToManyEntityBean;

import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.OrderBy;
import javax.persistence.Table;

@SuppressWarnings("serial")
@Entity
@Table(name = "Classes")
public class Classes {

	private Integer classesid;
	private String college;
	private String specialty;
	private String classesName;
	private Set<Student> students = new HashSet<Student>();

	@Id
	@GeneratedValue
	public Integer getClassesid() {
		return classesid;
	}

	public void setClassesid(Integer classesid) {
		this.classesid = classesid;
	}

	public String getCollege() {
		return college;
	}

	public void setCollege(String college) {
		this.college = college;
	}

	public String getSpecialty() {
		return specialty;
	}

	public void setSpecialty(String specialty) {
		this.specialty = specialty;
	}

	public String getClassesName() {
		return classesName;
	}

	public void setClassesName(String classesName) {
		this.classesName = classesName;
	}

	@OneToMany(mappedBy="classes",cascade = CascadeType.ALL, fetch = FetchType.LAZY)
	@OrderBy(value = "studentid ASC")
	public Set<Student> getStudents() {
		return students;
	}

	public void setStudents(Set<Student> students) {
		this.students = students;
	}

	public void addStudent(Student student) {
		if (!this.students.contains(student)) {
			this.students.add(student);
			student.setClasses(this);
		}
	}

	public void removeStudent(Student student) {
		student.setClasses(null);
		this.students.remove(student);
	}

}