Spring Data JPA:通过示例查询?

2022-01-18 00:00:00 spring java spring-data spring-data-jpa

使用 Spring Data JPA 我可以做一个 通过示例查询其中使用特定实体实例作为搜索条件?

Using Spring Data JPA can I do a query by example where a particular entity instance is used as the search criteria?

例如(没有双关语)，如果我有一个 Person 实体，看起来像:

For example (no pun intended), if I have a Person entity that looks like:

@Entity
public class Person {
  private String firstName;
  private String lastName;
  private boolean employed;
  private LocalDate dob;
  ...
}

我可以找到所有姓氏为 Smith 出生于 1977 年 1 月 1 日的雇员，例如:

I could find all employed persons with a last name of Smith born on January 1, 1977 with an example:

Person example = new Person();
example.setEmployed(true);
example.setLastName("Smith");
example.setDob(LocalDate.of(1977, Month.JANUARY, 1));
List<Person> foundPersons = personRepository.findByExample(example);

推荐答案

Spring 数据依赖于 JPA 和 EntityManager，而不是 Hibernate 和 Session，因此您没有开箱即用的 findByExample.您可以使用spring数据自动查询创建并在您的存储库中编写一个具有以下签名的方法:

Spring data relies on top of JPA and EntityManager, not Hibernate and Session, and as such you do not have findByExample out of the box. You can use the spring data automatic query creation and write a method in your repository with the following signature:

List<Person> findByEmployedAndLastNameAndDob(boolean employed, String lastName, LocalDate dob);

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