策略模式-如何为子类创建DTO

Question

public interface PersonCreationStrategy {
Person create(PersonCreateCommand command);

}

public class PersonCreateCommand {

private String type;
private Map<String , String> params;

}

public class PersonService {

private final Map<String, PersonCreationStrategy> creationStrategies;

public Person create(PersonCreateCommand command) {
    PersonCreationStrategy creationStrategy = creationStrategies.get(command.getType());
    if (creationStrategy == null) {
        throw new UnsupportedTypeException("unsupported type " + command.getType());
    }
    Person person = creationStrategy.create(command);
    return person;
}

}

我在我的应用程序策略模式中将不同类型的类存储到数据库中，我的主类是 Person 和 Person 之后的其他类继承，Person 类将所有类型存储在 SINGLE_TABLE 中，

现在我需要为子类执行 DTO，因为我需要返回附加值。

有人可以向我解释一下吗？如何以良好的方式做到这一点？

这是好方法吗？

    public Employee create(PersonCreateCommand command) {
   Map<String , String> params = command.getParams();
   return Employee.builder()
           .firstName(params.get("firstName"))
           .lastName(params.get("lastName"))
           .identifier(params.get("identifier"))
           .height(Long.parseLong(params.get("height")))
           .weight(Long.parseLong(params.get("weight")))
           .email(params.get("email"))
           .hireDate(LocalDate.parse(params.get("hireDate")))
           .jobPosition(params.get("jobPosition"))
           .salary(BigDecimal.valueOf(Long.parseLong(params.get("salary"))))
           .build();
}

Answer 1

更好的是重构：

public interface PersonCreationStrategy<T extends Person> {
T create(PersonCreateCommand command);
boolean accepts(String type);

}

public class PersonCreateCommand {

private String type;
private Map<String , String> params;

}

public class PersonService {

private final List<PersonCreationStrategy<? extends Person>> creationStrategies;

public Person create(PersonCreateCommand command) {
    PersonCreationStrategy creationStrategy = creationStrategies.stream().filter(s -> s.accepts(command.getType())).findFirst().orElseThrow(() ->
    new UnsupportedTypeException("unsupported type " + command.getType());

    Person person = creationStrategy.create(command);
    return person;
}

public class EmployeeCreationStrategy implements  PersonCreationStrategy<Employee> {
   public Employee create(PersonCreateCommand command){ ...
   public boolean accepts(String type){ EMPLYEE_TYPE.equals(type)};
}