我试图将实体扩展为非实体,用于填充超类的字段.问题是,当我尝试保存它时,Hibernate会抛出MappingException.这是因为即使我将ReportParser强制转换为Report,运行时实例仍然是ReportParser,因此Hibernate抱怨它是一个未知实体.
@Entity
@Table(name = "TB_Reports")
public class Report
{
Long id;
String name;
String value;
@Id
@GeneratedValue
@Column(name = "cReportID")
public Long getId()
{
return this.id;
}
public void setId(Long id)
{
this.id = id;
}
@Column(name = "cCompanyName")
public String getname()
{
return this.name;
}
public void setName(String name)
{
this.name = name;
}
@Column(name = "cCompanyValue")
public String getValue()
{
return this.name;
}
public void setValue(String value)
{
this.value = value;
}
}
ReportParser仅用于填写字段.
public class ReportParser extends report
{
public void setName(String htmlstring)
{
...
}
public void setValue(String htmlstring)
{
...
}
}
尝试将其转换为报告并保存
... ReportParser rp = new ReportParser(); rp.setName(unparsed_string); rp.setValue(unparsed_string); Report r = (Report)rp; this.dao.saveReport(r);
我在移动到ORM之前使用过这个模式,但是我无法弄清楚如何使用Hibernate.可能吗？
解决方法
是否绝对有必要对实体进行子类化？您可以使用构建器模式：
public class ReportBuilder {
private Report report;
public ReportBuilder() {
this.report = new Report();
}
public ReportBuilder setName(String unparsedString) {
// do the parsing
report.setName(parsedString);
return this;
}
public ReportBuilder setValue(String unparsedString) {
// do the parsing
report.setValue(parsedString);
return this;
}
public Report build() {
return report;
}
}
Report report = new ReportBuilder()
.setName(unparsedString)
.setValue(unparsedString)
.build();
dao.saveReport(report);
