在Hibernate中将另一个对象插入数据库之前，如何检查同一对象是否存在？

Question

Team.java

@Entity
@Table(name = "team")
public class Team {

@Id
@Column(name = "team_id")
@GeneratedValue(strategy = GenerationType.AUTO)
private int id;

@NotNull
@NotEmpty
@Size(max = 30)
private String leadName;

@NotNull
@NotEmpty
@Email(message = "email must be valid")
private String leadEmail;

@NotNull
@NotEmpty
@Size(max = 30)
private String teamName;

@ManyToOne
@JoinColumn(name = "city_id")
private City city;

@OneToMany( cascade = CascadeType.ALL)
@JoinColumn(name = "team_id")
private List<Idea> ideas;

@NotNull
@NotEmpty
private String organization;

...
}

这是JAVA Hibernate类（Spring Boot），并且存在TeamRepository类。插入之前，我想检查JPA信息库（TeamRepository）中是否存在相同的条目。休眠注释怎么办？可能吗？