Hibernate Annotation manytomay

与User多对多的角色类：

 /*
     * @ManyToMany 注释表示Teacher 是多对多关系的一端。
     * @JoinTable 描述了多对多关系的数据表关系，name属性指定中间表名称。
     * joinColumns 定义中间表与Teacher 表的外键关系，中间表Teacher_Student的Teacher_ID 列是Teacher 表的主键列对应的外键列。
     * inverseJoinColumns
 属性定义了中间表与另外一端(Student)的外键关系。
     */
    @ManyToMany
(cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
    @JoinTable
(name = 
"Teacher_Student"
,
            joinColumns ={@JoinColumn
(name = 
"teacher_ID"
, referencedColumnName = 
"teacherid"
) },
            inverseJoinColumns
 = { @JoinColumn
(name = 
"student_ID"
, referencedColumnName = 
"studentid"
)
    })
    public
 Set<Student> getStudents() {
        return
 students;
    }

@ManyToMany(cascade = { CascadeType.PERSIST, CascadeType.MERGE },targetEntity=Role.class)
	@JoinTable(name = "J_USER_ROLE", joinColumns = { @JoinColumn(name = "USER_ID") }, inverseJoinColumns = { @JoinColumn(name = "ROLE_ID") })
	@OrderBy("id")
	@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
	public Set<Role> getRoles() {
		return this.roles;
	}