java编写：存储多个员工信息（包括工号、姓名、年龄，入职时间），当有新员工入职时，添加其信息；当有员工离职时，删除其信息

1. 定义员工类Employee，包含工号、姓名、年龄、入职时间等属性和相应的get和set方法。

public class Employee {
private int id; //工号
private String name; //姓名
private int age; //年龄
private Date hireDate; //入职时间

public Employee(int id, String name, int age, Date hireDate) {
this.id = id;
this.name = name;
this.age = age;
this.hireDate = hireDate;
}

//getters and setters
public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public int getAge() {
return age;
}

public void setAge(int age) {
this.age = age;
}

public Date getHireDate() {
return hireDate;
}

public void setHireDate(Date hireDate) {
this.hireDate = hireDate;
}

}

2. 定义员工管理类EmployeeManager，包含一个List<Employee>用于存储所有员工信息，以及添加和删除员工的方法。

import java.util.ArrayList;
import java.util.Date;
import java.util.Iterator;
import java.util.List;

public class EmployeeManager {
private List<Employee> employees;

public EmployeeManager() {
employees = new ArrayList<Employee>();
}

//添加新员工
public void addEmployee(Employee employee) {
employees.add(employee);
}

//删除员工
public void removeEmployee(int id) {
Iterator<Employee> iterator = employees.iterator();
while (iterator.hasNext()) {
Employee employee = iterator.next();
if (employee.getId() == id) {
iterator.remove();
break;
}
}
}

//测试
public static void main(String[] args) {
EmployeeManager manager = new EmployeeManager();

//添加员工
Employee employee1 = new Employee(1, "张三", 25, new Date());
Employee employee2 = new Employee(2, "李四", 30, new Date());
manager.addEmployee(employee1);
manager.addEmployee(employee2);

//删除员工
manager.removeEmployee(2);

//输出员工信息
for (Employee employee : manager.employees) {
System.out.println(employee.getName());
}
}
}

运行结果为：

张三

说明已成功添加一个员工，删除一个员工，只剩下一个员工了。