我有这样的JPA实体类：

@Entity
@Table(name = "person")
public class Person {
   @Id
   private Long id;
   private String lastName;
   private String firstName;
   private String country;
   private String gender; 
...
//setters and getters are omitted
}

我需要这样的搜索方法 List<Person> findAll(Person searchCriteria)

用法示例：

Person criteria1 = new Person();
criteria1.setFristName("John");
criteria1.setCountry("Usa");

//returns all John from Usa with any lastName
List<Person> searchingResult = findAll(criteria1);

Person criteria2 = new Person();
criteria2.setGender("m");
criteria2.setCountry("Holland");

//returns all man from Holland
List<Person> anotherSearchingResult = findAll(criteria2);

我对findAll方法的想法是

String query = "select * from person where ";
if(criteria.getLastName() != null) query+= "last_name = "+ criteria.getLastName();
if(criteria.getGender() != null) query+= "gender = "+ criteria.getGender();
etc
List<Person> = session.execute(query);

但这太丑陋了，看起来有些开销。谁能帮助我findAll更礼貌地邀请该方法？我可以使用任何Java技术或框架。