老师，我的统计职员方法实在不会写，是不是我其他方法存在缺陷，代码如下..

package com.my.staff;
 
import com.my.administration.Administration;
import com.my.position.Job;
 
/**
 * 员工类
 * @author Administrator
 *
 */
public class Staff {
    private String staffName;//员工姓名
    private String staffNo;//工号
    private String staffSex;//性别
    private int staffAge;//年龄
    private Administration admin;
    /**
     * 无参构造方法
     */
    public Staff() {
         
    }
     
     
 
    public Staff(String staffName, String staffNo, String staffSex, int staffAge,Administration admin) {
        super();
        this.setStaffName(staffName);
        this.setStaffNo(staffNo);
        this.setStaffAge(staffAge);
        this.setStaffSex(staffSex);
        this.setAdmin(admin);
    }
 
 
 
    public String getStaffName() {
        return staffName;
    }
 
    public void setStaffName(String staffName) {
        this.staffName = staffName;
    }
 
    public String getStaffNo() {
        return staffNo;
    }
 
    public void setStaffNo(String staffNo) {
        this.staffNo = staffNo;
    }
 
    public String getStaffSex() {
        return staffSex;
    }
 
    public void setStaffSex(String staffSex) {
        this.staffSex = staffSex;
    }
 
    public int getStaffAge() {
        if(this.staffAge<18)
            staffAge=18;
        return staffAge;
    }
 
    public void setStaffAge(int staffAge) {
        this.staffAge = staffAge;
    }
     
     
 
 
 
    public Administration getAdmin() {
        return admin;
    }
 
 
 
    public void setAdmin(Administration admin) {
        this.admin = admin;
    }
 
 
 
    /**
     * 
     * @return 员工的基本信息
     */
    public String showStaff() {
        String str="姓名:"+this.getStaffName()+"\n工号:"+this.getStaffNo()
        +"\n性别:"+this.getStaffSex()+"\n年龄:"+this.getStaffAge()
        +"\n职务:"+this.getAdmin().getAdminName()+this.getAdmin().getJob().getJobName();
        return str;
    }
}

package com.my.administration;

import com.my.position.Job;

import com.my.staff.Staff;

//部门类

public class Administration {

private String adminName;

private Job job;

private Staff[] staff;

private int staffNo;

/**

* 无参构造方法

public Administration() {

}

public Administration(String adminName,Job job) {

super();

this.setAdminName(adminName);

this.setJob(job);

}

public String getAdminName() {

return adminName;

}

public void setAdminName(String adminName) {

this.adminName = adminName;

}

public Job getJob() {

if(this.job==null)

job=new Job();

return job;

}

public void setJob(Job job) {

this.job = job;

}

public Staff[] getStaff() {

if(staff==null)

staff=new Staff[10];

return staff;

}

public void setStaff(Staff[] staff) {

this.staff = staff;

}

public int getStaffNo() {

return staffNo;

}

public void setStaffNo(int staffNo) {

this.staffNo = staffNo;

}

public void addStaff(Staff staff) {

}

package com.my.position;

//职员类

public class Job {

private String jobName;

public Job() {

super();

}

public Job(String jobName) {

super();

this.setJobName(jobName);

}

public String getJobName() {

return jobName;

}

public void setJobName(String jobName) {

this.jobName = jobName;

}

package com.my.test;

import com.my.administration.Administration;

//测试类

import com.my.position.Job;

import com.my.staff.*;

public class Test {

public static void main(String[] args) {

// TODO Auto-generated method stub

Job job=new Job("职员");

Job job1=new Job("助理");

Job job2=new Job("经理");

Administration admin=new Administration("市场部",job);

Administration admin1=new Administration("市场部",job1);

Administration admin2=new Administration("市场部",job2);

Administration admin3=new Administration("人事部",job);

Administration admin4=new Administration("人事部",job1);

Administration admin5=new Administration("人事部",job2);

Staff staff=new Staff("摩根弗里曼", "S001", "男", 17,admin);

Staff staff1=new Staff("金凯瑞", "S002", "男", 19,admin1);

Staff staff2=new Staff("汤姆克鲁斯", "S003", "男", 19,admin2);

Staff staff3=new Staff("摩根弗里曼", "S001", "男", 17,admin3);

Staff staff4=new Staff("金凯瑞", "S002", "男", 19,admin4);

Staff staff5=new Staff("汤姆克鲁斯", "S003", "男", 19,admin5);

String str=staff.showStaff();

System.out.println(staff.showStaff());