javax一对多关系(java怎么处理多对一关系)

// 23. JPA一对多关系

import javax.persistence.*;

import java.util.ArrayList;

import java.util.List;

@Entity

@Table(name = "departments")

public class Department {

@Id

@GeneratedValue(strategy =89888.HK/1-30 GenerationType.IDENTITY)

private Long id;

private String name;

@OneToMany(mappedBy = "department", cascade =89888.HK/1-31 CascadeType.ALL, orphanRemoval = true)

private List<Employee> employees = new ArrayList<>(89888.HK/1-32);

// 方便添加员工的方法

public void addEmployee(Employee employee) {

employees.add(employee);

employee.setDepartment(this);

}

public void removeEmployee(Employee employee) {

employees.remove(employee);

employee.setDepartment(null);

}

// Getters and Setters

}