使用JPA单项一对多外键关联

这篇文章主要介绍了使用JPA单项一对多外键关联，具有很好的参考价值，希望对大家有所帮助。如有错误或未考虑完全的地方，望不吝赐教

JPA单项一对多外键关联

一对多即一个对象中包含又另外一个对象的集合。

User主表代码

@Table(name="USER") @Entity public class User { private Integer id; private String username; private String userpassword; private String useraddress; private List listOrder; @JoinColumn(name="LIST_ORDER") @OneToMany(fetch=FetchType.LAZY,cascade=CascadeType.REMOVE) public List getListOrder() { return listOrder; } public void setListOrder(List listOrder) { this.listOrder = listOrder; } @Id @TableGenerator(name="PK_PRIMARY", table="order_user_sque", pkColumnName="pk_column_name", pkColumnValue="pk_column", valueColumnName="pk_column_value", allocationSize=1) @GeneratedValue(strategy=GenerationType.TABLE,generator="PK_PRIMARY") public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } @Column(name="USERNAME") public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } @Column(name="USERPASSWORD") public String getUserpassword() { return userpassword; } public void setUserpassword(String userpassword) { this.userpassword = userpassword; } @Column(name="USERADDRESS") public String getUseraddress() { return useraddress; } public void setUseraddress(String useraddress) { this.useraddress = useraddress; } }

代码中：@JoinColumn(name="LIST_ORDER") -> 表示将外键名设置为LIST_ORDER

@OneToMany(fetch=FetchType.LAZY,cascade=CascadeType.REMOVE) -> OneToMany中fetch表示查询时的加载模式[懒加载还是积极加载],cascade属性表示要级联操作的模式，此处为删除主表后从表一并删除。

Order从表代码

@Entity @Table(name="ORDER_USER") public class Order { private Integer id; private String orderName; //private User user; @Id @GeneratedValue public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getOrderName() { return orderName; } public void setOrderName(String orderName) { this.orderName = orderName; } }