@OneToMany和@ManyToOne

还是之前举的 城市 和 学校之间的例子
一座城市可以有多个学校
而每个学校都只能在一个城市

City.java

package com.ctguyxr.satokendemo.entity;
import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import lombok.Data;
import javax.persistence.*;
import java.util.List;
/**
 * Created By Intellij IDEA
 *
 * @author Xinrui Yu
 * @date 2021/11/28 20:59 星期日
 */
@Entity
@Data
@Table(name = "t_city")
public class City {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;
    @JsonManagedReference
    @OneToMany(cascade = CascadeType.ALL)
    @JoinColumn(name = "city_id")
    private List<College> colleges;
}

College.java

package com.ctguyxr.satokendemo.entity;
import com.fasterxml.jackson.annotation.JsonBackReference;
import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonManagedReference;
import lombok.Data;
import javax.persistence.*;
import javax.persistence.criteria.CriteriaBuilder;
import java.util.List;
/**
 * Created By Intellij IDEA
 *
 * @author Xinrui Yu
 * @date 2021/11/28 21:00 星期日
 */
@Entity
@Data
@Table(name = "t_colleges")
public class College {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    private String name;
    @JsonBackReference
    @ManyToOne(cascade = CascadeType.ALL)
    private City city;
}

最后生成的表结构