Question

我正在研究一个REST API，我试图在会话中找到表现最好的n个。

这是存储用户信息的实体用户

@Entity
@Table(name = "user")
public class User implements Serializable {

    private static final long serialVersionUID = 7401548380514451401L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    Long id;

    @Column(name = "name")
    String name;

    @NotNull
    @Email
    @Column(name = "email")
    String email;

    @Column(name = "registration_number")
    String registrationNumber;
// getter and setter
}

这是保存会话详细信息的第二个实体：-

@Entity
@Table(name = "session")
public class Session implements Serializable {

    private static final long serialVersionUID = 0x7E414EAA3DB0C391L;

    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Id
    Long id;

    @Column(name = "start_time")
    @NotNull
    String startTime;

    @Column(name = "end_time")
    @NotNull
    String endTime;

    @Column(name = "distance")
    Long distance;

    @JoinColumn(name = "driver_id", referencedColumnName = "id")
    @ManyToOne
    User trainer;

    @JoinColumn(name = "sessionr_id", referencedColumnName = "id")
    @ManyToOne
    User trainee;  //getter and setters

}

这是第三个用于保存会话和用户实体结果的模型

公共类TopTrainer {

private String name;

private String email;

private Long totalSessionDurationInSeconds;

private Long maxSessionDurationInSecods;

private Double averageDistance;

/**
 * Constructor for TopTrainer
 * 
 * @param name
 * @param email
 * @param totalSessionDurationInSeconds
 * @param maxSessionDurationInSecods
 * @param averageDistance
 */
public TopTrainer(String name, String email, Long totalSessionDurationInSeconds, Long maxSessionDurationInSecods,
        Double averageDistance) {
    this.setName(name);
    this.setEmail(email);
    this.setAverageDistance(averageDistance);
    this.setMaxSessionDurationInSecods(maxSessionDurationInSecods);
    this.setTotalSessionDurationInSeconds(totalSessionDurationInSeconds);

}

public TopTrainer() {

}

//Getter and Setter}

这是调用培训师服务以获得所需结果的控制器

@GetMapping(path = "/api/top-trainer")
    public ResponseEntity<List<TopTrainer>> getTopTrainer(@RequestParam(value = "max", defaultValue = "5") Long count,
            @RequestParam(value = "startTime", required = true) @DateTimeFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss") LocalDateTime startTime,
            @RequestParam(value = "endTime", required = true) @DateTimeFormat(pattern = "yyyy-MM-dd'T'HH:mm:ss") LocalDateTime endTime) {
        //To do

    }

我被困在这里已经很长时间了。在其中，根据他们的平均会话次数，所选的总会话时间和最大会话时间，我在所选时间戳之间列出了前n名教练。

我是JPA (CrudRepository<Session,Long>) 的新手，我无法理解如何提取所需的结果以及如何对实体执行聚合。

@RestResource(exported = false)
public interface SessionRepository extends CrudRepository<Session, Long> {

  Optional<List<TopTrainer>> findByStartTimeAfterAndEndTimeBefore(String startTime, String endTime);

}

任何人都可以]回答此问题。我们也可以使用条件查询

表演时间最长的前n名表演者，并显示该时间段内的平均距离

0 个答案: