Configure Hibernate with annotation (2): one-to-many relationship configuration

Data table structure

One-way pair

Student.java

1 @Entity2@Table (name = "Student")3  Public classStudent {4 @Id5@Column (name = "id")6@GenericGenerator (name = "Generator", strategy = "native")7@GeneratedValue (generator = "Generator")8     Private intID;9     Ten@Column (name = "Name") One     PrivateString name; A      -@ManyToOne (cascade=cascadetype.all,fetch=Fetchtype.eager) -@JoinColumn (name= "grade_id") the     PrivateGrade Grade; -}

Grade.java

1 @Entity2@Table (name= "Grade")3  Public classGrade {4 @Id5@Column (name = "id")6@GenericGenerator (name = "Generator", strategy = "native")7@GeneratedValue (generator = "Generator")8     Private intID;9     Ten@Column (name = "Name") One     PrivateString name; A}

One-way many-to-one

Student.java

@Entity @table (name= "Student") Public classStudent {@Id @Column (name= "id") @GenericGenerator (name= "Generator", strategy = "native") @GeneratedValue (generator= "Generator")    Private intID; @Column (Name= "Name")    PrivateString name; @ManyToOne (Cascade=cascadetype.all,fetch=Fetchtype.eager) @JoinColumn (name= "grade_id")    PrivateGrade Grade;}

Grade.java

1 @Entity2@Table (name= "Grade")3  Public classGrade {4 @Id5@Column (name = "id")6@GenericGenerator (name = "Generator", strategy = "native")7@GeneratedValue (generator = "Generator")8     Private intID;9     Ten@Column (name = "Name") One     PrivateString name; A}

Bidirectional correlation

Student.java

1 @Entity2@Table (name = "Student")3  Public classStudent {4 @Id5@Column (name = "id")6@GenericGenerator (name = "Generator", strategy = "native")7@GeneratedValue (generator = "Generator")8     Private intID;9     Ten@Column (name = "Name") One     PrivateString name; A      -@ManyToOne (cascade=cascadetype.all,fetch=Fetchtype.eager) -@JoinColumn (name= "grade_id") the     PrivateGrade Grade; -}

Grade.java

1 @Entity2@Table (name= "Grade")3  Public classGrade {4 @Id5@Column (name = "id")6@GenericGenerator (name = "Generator", strategy = "native")7@GeneratedValue (generator = "Generator")8     Private intID;9     Ten@Column (name = "Name") One     PrivateString name; A      -@OneToMany (cascade=cascadetype.all,fetch=fetchtype.eager,mappedby= "Grade") -     Privateset<student> students =NewHashset<student>();  the}

Own one-to-many

Category.java

1 @Entity2@Table (name = "category")3  Public classCategory {4 @Id5@Column (name = "id")6@GenericGenerator (name = "Generator", strategy = "native")7@GeneratedValue (generator = "Generator")8     Private intID;9     Ten@OneToMany (cascade=cascadetype.all,fetch=fetchtype.lazy,mappedby= "category") One     PrivateSet<category> Categorys =NewHashset<category>(); A      -@ManyToOne (cascade=cascadetype.all,fetch=Fetchtype.eager) -@JoinColumn (name= "Father_category") the     PrivateCategory category; -  -}

The specific role of the Mappedby keyword can be consulted http://xiaoruanjian.iteye.com/blog/1094253