英文:
spring data, PagingAndSorting repository, Sort based on (nested) attribute value of class type
问题
以下是您要翻译的内容：
我有一个用于简单应用程序的PagingAndSorting存储库，其中包含人员信息。
像年龄这样的属性的简单排序效果不错...
Sort sort = Sort.by("age").ascending();
for (Person p : personRepository.findAll(sort)) {
log.info(p.toString());
}
我还想按lastName对人员进行排序。但是我没有为名和姓各创建两个属性。我创建了一个Name类，它包含名和姓，并在Person中创建了一个名为name的此类型属性...
@Entity
public class Person {
// ...
@Convert(converter = NameAttributeConverter.class)
@Column
private Name name;
// ...
}
public final class Name implements Comparable, Serializable {
// ...
private String firstName;
private String lastName;
// ...
}
public class NameAttributeConverter implements AttributeConverter<Name, String> {
{
String firstName = attribute.getFirstName() == null ? " " : attribute.getFirstName();
String lastName = attribute.getLastName() == null ? " " : attribute.getLastName();
return firstName + " " + lastName;
}
public Name convertToEntityAttribute(String dbData) {
if(dbData != null && dbData.split(" ").length > 0) {
String fname = dbData.split(" ")[0];
String lname = dbData.split(" ")[1];
return new Name(fname, ' ', lname);
}
return null;
}
}
如何按lastName（或firstName）排序？类似于
Sort sort = Sort.by("name").ascending();
for (Person p : personRepository.findAll(sort)) {
log.info(p.toString());
}
执行并且没有错误（例如人员在控制台上打印出来），但不起作用（如预期所望）。
它使用firstName升序排序（不知道为什么）。
如何根据类名的lastName属性实现排序？
谢谢和问候。
英文:
I have a PagingAndSorting repository for a simple application which consists of Persons.
A simple sort for a property like age works well...
Sort sort = Sort.by("age").ascending();
for (Person p : personRepository.findAll(sort)) {
log.info(p.toString());
}
I want to sort persons by lastName as well. But I dont create two attributes for first and last name. I created a class Name which holds first and last name and make an name attribute of this type in Person...
@Entity
public class Person {
// ...
@Convert(converter = NameAttributeConverter.class)
@Column
private Name name;
// ...
}
public final class Name implements Comparable, Serializable {
// ...
private String firstName;
private String lastName;
// ...
}
public class NameAttributeConverter implements AttributeConverter<Name,String> {
{
String firstName = attribute.getFirstName() == null ? " " : attribute.getFirstName();
String lastName = attribute.getLastname() == null ? " " : attribute.getLastname();
return firstName+" "+lastName;
}
public Name convertToEntityAttribute(String dbData) {
if(dbData!=null && dbData.split(" ").length > 0) {
String fname = dbData.split(" ")[0];
String lname = dbData.split(" ")[1];
return new Name(fname,' ',lname);
}
return null;
}
}
How can I sort by lastName (or firstName)? Something like
Sort sort = Sort.by("name").ascending();
for (Person p : personRepository.findAll(sort)) {
log.info(p.toString());
}
executes and brings no error (e.g. persons are printed on console) but doesnt work like expected.
It sorts ascending using the firstName (dont no why).
How can I acieve a sorting based on the lastName attribute of the class name?
Thanks and regards
答案1
得分: 1
你正在将name列的数据存储为数据库中的firstName+" "+lastName。
因此，JPA按照名称对数据进行排序，意味着按照firstName+" "+lastName进行排序。
如果您在数据库中单独定义了firstname和lastname列，则可以通过lastname进行排序。
您可以在此处查看我的答案这里以解决此问题。
英文:
You are storing name column's data as firstName+" "+lastName in database.
So JPA sort data by name means sort by firstName+" "+lastName.
If you define firstname and lastname in database separate column then its possible to sort by lastname also.
You can follow my answer here for solve this issue.
专注分享java语言的经验与见解，让所有开发者获益！
评论