求Java练习的代码！

求Java练习的代码！

可能会有BUG，但是大概的思路应该写清楚了。
对于最后的薪金没有做四舍五入处理
包名：com.salary
下面是代码：

WorkTime.java：================================================================
package com.salary;

public class WorkTime {

public static final int NIGHT_WORK_TIME = 6*60;//到6点的分钟数

private int startHour,startMinute,endHour,endMinute;

public WorkTime(int startHour,int startMinute,int endHour,int endMinute){
this.startHour = startHour;
this.startMinute = startMinute;
this.endHour = endHour;
this.endMinute = endMinute;
}


public int getAllWorkTime(){
int beginWorkTime = getMinutes(startHour,startMinute);
int endWorkTime = getMinutes(endHour,endMinute);

if(beginWorkTime == endWorkTime){
return 24*60;
}

if(endWorkTime<beginWorkTime){
endWorkTime+=24*60;
}

int totalWorkTime = endWorkTime-beginWorkTime;

return totalWorkTime;
}


public int getDayWorkTime(){
int dayWorkTime = getAllWorkTime()-getNightWorkTime();
return dayWorkTime;
}


public int getNightWorkTime(){
int beginMinutes = getMinutes(startHour,startMinute);
int endMinutes = getMinutes(endHour,endMinute);

if(endMinutes<=NIGHT_WORK_TIME){
return endMinutes;
}else if(beginMinutes>=endMinutes){
return NIGHT_WORK_TIME;
}
return 0;
}

private int getMinutes(int hour,int minute){
return hour*60+minute;
}

}
SalaryCalculation.java=============================================================
package com.salary;

public abstract class SalaryCalculation {


public abstract double salaryUnit();


public double salaryCalculate(int hour,int minute){
double hourSalary = salaryUnit()*hour;
double minuteSalary = salaryUnit()*(minute/60);
return hourSalary+minuteSalary;
}


public double salaryCalculate(int minutes){
double hourSalary = salaryUnit()*(minutes/60);
double minuteSalary = salaryUnit()*(minutes%60.0/60);
return hourSalary+minuteSalary;
}

}

DaySalary.java===================================================================
package com.salary;


public class DaySalary extends SalaryCalculation{

public double salaryUnit() {
return 3.4;
}

}

NightSalary.java===================================================================
package com.salary;

public class NightSalary extends SalaryCalculation{

public double salaryUnit() {
return 3.9;
}

}
最后是测试类代码==================================================================
package com.salary;

public class Test {

public static void main(String[] args) {

WorkTime workTime = new WorkTime(22, 0, 2, 20);//从晚上22:00点做到凌晨2:20
int dayWorkTime = workTime.getDayWorkTime();//得到白天的工时
int nightWorkTime = workTime.getNightWorkTime();//得到夜间的工时

double daySalary = new DaySalary().salaryCalculate(dayWorkTime);//计算白天的薪金
double nightSalary = new NightSalary().salaryCalculate(nightWorkTime);//计算夜间的薪金

double salary = daySalary+nightSalary;//计算总薪金
System.out.println(salary);
}
}

输出为：16.55