有两张表,table1和table2.产生此问题的原因就是table1里做了关联<one-to-one>或者<many-to-one unique="true">(特殊的多对一映射,实际就是一对一)来关联table2.当hibernate查找的时候,table2里的数据没有与table1相匹配的,这样就会报No row with the given identifier exists这个错.(一句话,就是数据的
现在hibernate配置可以基于xml配置文件和注解方式,这两种方式都能发生这个异常
xml配置文件解决方法:
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<many-to-one class="com.art.model.user.UserInfo" fetch="join" name="userInfo" >
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<column name="userId" unique="true"/>
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</many-to-one>
修改后的:
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<many-to-one class="com.art.model.user.UserInfo" fetch="join" name="userInfo" not-found="ignore">
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<column name="userId" unique="true"/>
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</many-to-one>
红色是修改的部分。意思是当对应的数据不存在时 忽略掉,用null值填充。该属性默认值:exception 。
注解配置解决方法:
使用hibernate 注解配置实体类的关联关系,在many-to-one,one-to-one关联中,一边引用自另一边的属性,如果属性值为某某的数据在数据库不存在了,hibernate默认会抛出异常。解决此问题,加上如下注解就可以了:
@NotFound(action=NotFoundAction.IGNORE),意思是找不到引用的外键数据时忽略,NotFound默认是exception
下面贴出hibernate 注解的实例代码
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@Entity
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@Table(name = "ICT_COMPUTER_LOCATION")
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public class IctComputerLocation {
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private static final long serialVersionUID = 1L;
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private Integer id;
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/** IDC编号 */
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private String idcNum;
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private Integer ictBaseId;
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/** IctBase实体类 */
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private IctBase ictBase;
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@Id
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@GeneratedValue(strategy = GenerationType.AUTO)
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@Column(name = "ID")
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public Integer getId() {
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return id;
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}
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public void setId(Integer id) {
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this.id = id;
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}
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@Column(name = "IDC_NUM")
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public String getIdcNum() {
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return idcNum;
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}
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public void setIdcNum(String idcNum) {
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this.idcNum = idcNum;
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}
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@Column(name = "ICT_BASE_ID")
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public Integer getIctBaseId() {
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return ictBaseId;
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}
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public void setIctBaseId(Integer ictBaseId) {
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this.ictBaseId = ictBaseId;
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}
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@ManyToOne(fetch = FetchType.LAZY)
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@JoinColumn(name = "ICT_BASE_ID", referencedColumnName = "ID", unique = false, nullable = false, insertable = false, updatable = false)
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@NotFound(action=NotFoundAction.IGNORE)
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public IctBase getIctBase() {
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return ictBase;
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}
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public void setIctBase(IctBase ictBase) {
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this.ictBase = ictBase;
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}