求助,jpa为含有复合主键如何建立一对多的关联

发布网友发布时间：2022-04-26 00:18

共3个回答

懂视网时间：2022-04-15 03:34

http://note.youdao.com/share/?id=9065b839f2d6b3f1b6310ad9bb92d3f6type=note @Entity@Table(name = RELEASE_INFO_ELEMENT)public class ReleaseInfoElement { @EmbeddedId private PK pk = new PK(); @Column(name = VALUE) private String value; public

http://note.youdao.com/share/?id=9065b839f2d6b3f1b6310ad9bb92d3f6&type=note

@Entity @Table(name = "RELEASE_INFO_ELEMENT") public class ReleaseInfoElement { @EmbeddedId private PK pk = new PK(); @Column(name = "VALUE") private String value; public Long getInfoId() { return pk.infoId; } public void setInfoId(Long infoId) { pk.infoId = infoId; } public Long getParamId() { return pk.paramId; } @Override public String toString() { return "ReleaseInfoElement [infoId=" + pk.infoId + ", paramId=" + pk.paramId + ", value=" + value + "]"; } public void setParamId(Long paramId) { pk.paramId = paramId; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } @Embeddable public static class PK implements Serializable { @Column(name = "INFO_ID") private Long infoId; @Column(name = "PARAM_ID") private Long paramId; public PK() { super(); } } }

热心网友时间：2022-04-15 00:42

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！

热心网友时间：2022-04-15 02:00

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。