如何获得 java 8 中两个不同类的内连接结果

Question

Is there a way to carry out and get the result of inner join between two different classes in java. For example I have:

class A

public class A {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
    @ManyToOne
    private B b;
}

class B

public class B {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;
}

I want to carry out a Inner join based on a single field id . Is it possible to have those result? which way? Thank you

Answer 1

There is annotation in JPA

@JoinColumn(name = "nameOfColumn")

use it under

@ManyToOne
private B b;

Answer 2

@ManyToOne

@JoinColumn(name = "foreign_key" referencedColumnName = "primary/referenced key")

private B b;

Please refer to: https://vladmihalcea.com/how-to-map-a-manytoone-association-using-a-non-primary-key-column/