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;
	}