定义Staff类(职工)，添加如下属性(name, address, age, sex, salary, dateHired)，类型自定，其中salary为工资，dateHired为雇佣日期(java.util.Date类型)。生成相应的setter/getter方法。 (2)编写Teacher类(教师)，继承自Staff类，包含属性：department(系), speciality(专业), postAllowance(岗位津贴)。 (3)编写SecurityGuard类(保安)，继承自Staff

类，包含属性：level(级别)，workHours(工作时长)。

代码如下：

import java.util.Date;

public class Staff {
    private String name;
    private String address;
    private int age;
    private String sex;
    private double salary;
    private Date dateHired;
    
    public Staff(String name, String address, int age, String sex, double salary, Date dateHired) {
        this.name = name;
        this.address = address;
        this.age = age;
        this.sex = sex;
        this.salary = salary;
        this.dateHired = dateHired;
    }
    
    public String getName() {
        return name;
    }
    
    public void setName(String name) {
        this.name = name;
    }
    
    public String getAddress() {
        return address;
    }
    
    public void setAddress(String address) {
        this.address = address;
    }
    
    public int getAge() {
        return age;
    }
    
    public void setAge(int age) {
        this.age = age;
    }
    
    public String getSex() {
        return sex;
    }
    
    public void setSex(String sex) {
        this.sex = sex;
    }
    
    public double getSalary() {
        return salary;
    }
    
    public void setSalary(double salary) {
        this.salary = salary;
    }
    
    public Date getDateHired() {
        return dateHired;
    }
    
    public void setDateHired(Date dateHired) {
        this.dateHired = dateHired;
    }
}

public class Teacher extends Staff {
    private String department;
    private String speciality;
    private double postAllowance;
    
    public Teacher(String name, String address, int age, String sex, double salary, Date dateHired, String department, String speciality, double postAllowance) {
        super(name, address, age, sex, salary, dateHired);
        this.department = department;
        this.speciality = speciality;
        this.postAllowance = postAllowance;
    }
    
    public String getDepartment() {
        return department;
    }
    
    public void setDepartment(String department) {
        this.department = department;
    }
    
    public String getSpeciality() {
        return speciality;
    }
    
    public void setSpeciality(String speciality) {
        this.speciality = speciality;
    }
    
    public double getPostAllowance() {
        return postAllowance;
    }
    
    public void setPostAllowance(double postAllowance) {
        this.postAllowance = postAllowance;
    }
}

public class SecurityGuard extends Staff {
    private int level;
    private int workHours;
    
    public SecurityGuard(String name, String address, int age, String sex, double salary, Date dateHired, int level, int workHours) {
        super(name, address, age, sex, salary, dateHired);
        this.level = level;
        this.workHours = workHours;
    }
    
    public int getLevel() {
        return level;
    }
    
    public void setLevel(int level) {
        this.level = level;
    }
    
    public int getWorkHours() {
        return workHours;
    }
    
    public void setWorkHours(int workHours) {
        this.workHours = workHours;
    }
}