Question

求助，jpa为含有复合主键如何建立一对多的关联

Answer 1

您好，很高兴为您解答：

@OneToMany(cascade = CascadeType.ALL , fetch = FetchType.LAZY)
@JoinColumn(name = "app_no")
public Set<NameAppInvest> getNameAppInvestsSet() {
return nameAppInvestsSet;
}

public void setNameAppInvestsSet(Set<NameAppInvest> nameAppInvestsSet) {
this.nameAppInvestsSet = nameAppInvestsSet;
}

这是我建立的一对多的关联

public void deleteApply(String appNo, int loadMode){
NameApp nameApp = null ;
if(StringUtils.isNotBlank(appNo)){
//得到名称申请案
nameApp = entityDAO.getNameApp(appNo);
}
if(nameApp != null){
if(loadMode == 0){
CascadeUtil.lazyInit(nameApp); // 加载全部Set
}

//删除名称申请案
entityDAO.deleteNameApp(nameApp);

}
}

希望以上信息可以帮到您！

Answer 2

进行面向对象的分析，uer和role之间是双向多对多联系，使用JPA配置如下所示：
@Entity
public class User implements Serizlizable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String userName;
private String passWord;
@ManyToMany(cascade = CascadeType.ALL)
private List<Role> roles;
......
......
}

@Entity
public class Role implements Serizlizable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
private String role;
@ManyToMany(mappedBy = "roles")
private User user;
......
......
}

配置后，会在数据库中生存你想要的3个表。