consortium.java

EJB3.0实现学生、社团实体及它们的M:M关系

package ManyToManyEntityBean;

import javax.persistence.Entity;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@SuppressWarnings("serial")
@Entity
@Table(name = "Consortium")
public class Consortium implements Serializable {
	private Integer consortiumid;
	private String consortiumName;
	private Set<Student> students = new HashSet<Student>();

	public Consortium() {
	}

	public Consortium(String consortiumName) {
		this.consortiumName = consortiumName;
	}

	@Id
	@GeneratedValue
	public Integer getConsortiumid() {
		return consortiumid;
	}

	public void setConsortiumid(Integer consortiumid) {
		this.consortiumid = consortiumid;
	}

	@Column(nullable = false)
	public String getConsortiumName() {
		return consortiumName;
	}

	public void setConsortiumName(String consortiumName) {
		this.consortiumName = consortiumName;
	}

	@ManyToMany(cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
	@JoinTable(name = "Consortium_Student", joinColumns = { @JoinColumn(name = "Consortium_ID", referencedColumnName = "consortiumid") }, inverseJoinColumns = { @JoinColumn(name = "Student_ID", referencedColumnName = "studentid") })
	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);
		}
	}

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

}