我想将本机查询中的数据映射到包含列表的对象。
假设我有这个问题（这是我想要做的一个人为的例子）
select p.id, p.name, a.address, a.city, s.salestotal, s.salesmonth
from person p, address a, sales s where <Joined somehow>
它返回此数据
1 John 123 This Street 100 June
1 John 456 That Street 100 June
1 John 789 There Street 100 June
2 Bill 987 Apple Street 321 April
2 Bill 654 Banana Street 321 April
2 Bill 321 Orange Street 321 April
2 Bill 741 Pear Street 321 April
3 Mary 951 Oak Ave 195 May
请注意，人员和销售人员的数据会重复，但地址是唯一的。
所以我想把它映射到一个看起来像这样的对象：
public class PersonSalesAddressSummary{
private Person person;
private Sales sales;
private List<Address> addresses;
//getters and setters etc...
}
其中Person，Sales和Address都是映射实体。
我最想得到的是3 PersonSalesAddressSummary的列表，但我不确定如何设置结果集映射......我认为这是可能的，但我不知道从哪里开始。甚至一些关于如何正确地表达这个问题的帮助也会有所帮助！
编辑： 更清楚的是，我想最终得到的一个目标是：
PersonSalesAddressSummary
Person = 1 John
Sales = 100 June
List<Address> = 123 This Street,
456 That Street,
789 There Street
至少我希望更清楚
答案 0 :(得分：1)
正如@Nicholas所说，SqlResultSetMapping只会映射列或实体。恕我直言，这是针对您的特殊映射案例的解决方案之一
你的SqlResultSetMapping可能是
@SqlResultSetMapping(name = "PersonSalesAddressSummaryDTOMapping",
classes = @ConstructorResult(
targetClass = PersonSalesAddressSummary.class,
columns = {
@ColumnResult(name = "id", type = Integer.class),
@ColumnResult(name = "name"),
@ColumnResult(name = "address"),
@ColumnResult(name = "city"),
@ColumnResult(name = "salestotal", type = Integer.class),
@ColumnResult(name = "salesmonth"),
})
）
和PersonSalesAddressSummary DTO，对不起详细的源代码
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
public class PersonSalesAddressSummary {
private static Map<PersonSales, List<Address>> mapPersonSales = new HashMap<>();
private Person person;
private Sales sales;
private List<Address> addresses;
public PersonSalesAddressSummary(Integer id, String name, String address, String city, Integer salestotal, String salesmonth) {
Person p = new Person(id, name);
Sales s = new Sales(salestotal, salesmonth);
PersonSales ps = new PersonSales(p,s);
Address a = new Address(address,city);
Optional<List<Address>> addressList = Optional.ofNullable(mapPersonSales.get(ps));
if(addressList.isPresent()){
addressList.get().add(a);
}else{
List<Address> addresses = new ArrayList<>();
addresses.add(a);
mapPersonSales.put(ps, addresses);
}
}
class PersonSales {
private Person person;
private Sales sales;
public PersonSales(Person person, Sales sales) {
this.person = person;
this.sales = sales;
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
public Sales getSales() {
return sales;
}
public void setSales(Sales sales) {
this.sales = sales;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
PersonSales that = (PersonSales) o;
return Objects.equals(person.getId(), that.getPerson().getId())
&& Objects.equals(person.getName(), that.getPerson().getName())
&& Objects.equals(sales.getAmount(), that.getSales().getAmount())
&& Objects.equals(sales.getMonth(), that.getSales().getMonth())
;
}
@Override
public int hashCode() {
return Objects.hash(person.getId(), person.getName(), sales.getAmount(), sales.getMonth());
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder("PersonSalesAddressSummary ").append("\n");
sb.append("Person = ").append(person.getId()).append(" ").append(person.getName()).append("\n");
sb.append("Sales = ").append(sales.getAmount()).append(" ").append(sales.getMonth()).append("\n");
return sb.toString();
}
}
class Person {
private Integer id;
private String name;
public Person(Integer id, String name) {
this.id = id;
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Person person = (Person) o;
return Objects.equals(id, person.id) &&
Objects.equals(name, person.name);
}
@Override
public int hashCode() {
return Objects.hash(id, name);
}
}
class Sales {
private Integer amount;
private String month;
public Sales(Integer amount, String month) {
this.amount = amount;
this.month = month;
}
public Integer getAmount() {
return amount;
}
public void setAmount(Integer amount) {
this.amount = amount;
}
public String getMonth() {
return month;
}
public void setMonth(String month) {
this.month = month;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Sales sales = (Sales) o;
return Objects.equals(amount, sales.amount) &&
Objects.equals(month, sales.month);
}
@Override
public int hashCode() {
return Objects.hash(amount, month);
}
}
class Address {
private String address;
private String city;
public Address(String address, String city) {
this.address = address;
this.city = city;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder("Address ");
sb.append(" = ").append(address);
sb.append(" ").append(city);
return sb.toString();
}
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person = person;
}
public Sales getSales() {
return sales;
}
public void setSales(Sales sales) {
this.sales = sales;
}
public List<Address> getAddresses() {
return addresses;
}
public void setAddresses(List<Address> addresses) {
this.addresses = addresses;
}
public static void main(String[] args){
new PersonSalesAddressSummary(1, "John", "123", "This Street", 100, "June");
new PersonSalesAddressSummary(1, "John", "456", "This Street", 100, "June");
new PersonSalesAddressSummary(1, "John", "789", "There Street", 100, "June");
new PersonSalesAddressSummary(2, "Bill", "987", "Apple Street", 321, "April");
new PersonSalesAddressSummary(2, "Bill", "654", "Banana Street", 321, "April");
new PersonSalesAddressSummary(2, "Bill", "321", "Orange Street", 321, "April");
new PersonSalesAddressSummary(2, "Bill", "741", "Pear Street", 321, "April");
new PersonSalesAddressSummary(3, "Mary", "951", "Oak Ave", 195, "May");
mapPersonSales.entrySet().stream().forEach(System.out::println);
}
}
输出
PersonSalesAddressSummary
Person = 3 Mary
Sales = 195 May
=[Address = 951 Oak Ave]
PersonSalesAddressSummary
Person = 2 Bill
Sales = 321 April
=[Address = 987 Apple Street, Address = 654 Banana Street, Address = 321 Orange Street, Address = 741 Pear Street]
PersonSalesAddressSummary
Person = 1 John
Sales = 100 June
=[Address = 123 This Street, Address = 456 This Street, Address = 789 There Street]
如果我有任何错误，请纠正我，非常感谢
答案 1 :(得分：0)
据我所知，您无法从本机查询中提取父级＆gt;子关系。原生查询总是会为您提供原始行，可以是对象，也可以是元组，但是您可以将它映射到对象。