学以致用——Java源码——员工薪酬系统功能增强（Payroll System Modification）

程序功能：

1. 基类：Emplyee（普通员工）（姓名、生日、身份证号）

2. 直接子类：SalariedEmployee（固定工资员工），HourlyEmployee（小时工）、CommissionEmployee（提成工资员工）

3. 间接子类：BasePlusCommissionEmployee（基本工资加提成工资员工）

4. 打印不同员工的信息

5. 为BasePlusCommissionEmployee类型的员工增加10%的基础工资

6. 如果遇到员工的生日，该员工当月的工资增加100

运行结果：

Employees processed individually:

salaried employee: John Smith

出生年月日: 1980年10月1日

social security number: 111-11-1111

weekly salary: $800.00

earned: $800.00

hourly employee: Karen Price

出生年月日: 1970年1月31日

social security number: 222-22-2222

hourly wage: $16.75; hours worked: 40.00

earned: $670.00

commission employee: Sue Jones

出生年月日: 1990年1月18日

social security number: 333-33-3333

gross sales: $10,000.00; commission rate: 0.06

earned: $600.00

base-salaried commission employee: Bob Lewis

出生年月日: 1992年5月20日

social security number: 444-44-4444

gross sales: $5,000.00; commission rate: 0.04; base salary: $300.00

earned: $500.00

Employees processed polymorphically:

salaried employee: John Smith

出生年月日: 1980年10月1日

social security number: 111-11-1111

weekly salary: $800.00

earned $800.00

hourly employee: Karen Price

出生年月日: 1970年1月31日

social security number: 222-22-2222

hourly wage: $16.75; hours worked: 40.00

earned $770.00

commission employee: Sue Jones

出生年月日: 1990年1月18日

social security number: 333-33-3333

gross sales: $10,000.00; commission rate: 0.06

earned $700.00

base-salaried commission employee: Bob Lewis

出生年月日: 1992年5月20日

social security number: 444-44-4444

gross sales: $5,000.00; commission rate: 0.04; base salary: $300.00

new base salary with 10% increase is: $330.00

earned $530.00

Employee 0 is a exercises.ch10PolymorphismAndInteface.SalariedEmployee

Employee 1 is a exercises.ch10PolymorphismAndInteface.HourlyEmployee

Employee 2 is a exercises.ch10PolymorphismAndInteface.CommissionEmployee

Employee 3 is a exercises.ch10PolymorphismAndInteface.BasePlusCommissionEmployee

代码：

1. 实体类

1) Date类

import java.util.Calendar;//JHTP Exercise 8.8: Enhancing Class Date
//by pandenghuang@163.com
/*** 8.8 (Enhancing Class Date) Modify class Date of Fig. 8.7 to perform error* checking on the initializer values for instance variables month, day and year* (currently it validates only the month and day). Provide a method nextDay to* increment the day by one. Write a program that tests method nextDay in a loop* that prints the date during each iteration to illustrate that the method* works correctly. Test the following cases: a) incrementing into the next* month and b) incrementing into the next year.* * 8.14 (Date Class) Create class Date with the following capabilities: a)* Output the date in multiple formats, such as 1. MM/DD/YYYY 2. June 14, 1992 3. DDD* YYYY b) Use overloaded constructors to create Date objects initialized with* dates of the formats in part (a). In the first case the constructor should* receive three integer values. In the second case it should receive a String* and two integer values. In the third case it should receive two integer* values, the first of which represents the day number in the year. [Hint: To* convert the String representation of the month to a numeric value, compare* Strings using the equals method. For example, if s1 and s2 are Strings, the* method call s1.equals(s2) returns true if the Strings are identical and* otherwise returns false.]* *//*** * @author Pandenghuang@163.com* @Date Jan 7, 2019, 12:35:19 AM**/
public class Date {private int month; // 1-12private int day; // 1-31 based on monthprivate int year; // any yearprivate static final int[] daysPerMonth = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };//constructor: confirm proper value for month and day given the year/*** 使用年月日构建日期，如new Date(2019,1,7)将构建2019年1月7日* @Date Jan 7, 2019, 12:35:31 AM* @param year* @param month* @param day*/public Date(int year, int month, int day) {// check for year up to next year and later than 1918 //2018年12月添加if (year < 1918 || year > Calendar.getInstance().get(Calendar.YEAR) + 100) // 获取下一年的下100年throw new IllegalArgumentException("year (" + day + ") out-of-range. A year later than 1918 and up to next 100 years is expected.");// check if month in rangeif (month <= 0 || month > 12)throw new IllegalArgumentException("month (" + month + ") must be 1-12");// check if day in range for monthif (day <= 0 || (day > daysPerMonth[month] && !(month == 2 && day == 29)))throw new IllegalArgumentException("day (" + day + ") out-of-range for the specified month and year");// check for leap year if month is 2 and day is 29// 闰年判定规则：能被400整除，或，能被4整除但不能被100整除if (month == 2 && day == 29 && !(year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)))throw new IllegalArgumentException("day (" + day + ") out-of-range for the specified month and year");this.month = month;this.day = day;this.year = year;//System.out.printf( "日期对象创建成功：%s%n", this);}//无参构造函数，创建当前日期public Date() {this.year = Calendar.getInstance().get(Calendar.YEAR);this.month = Calendar.getInstance().get(Calendar.MONTH) + 1;this.day = Calendar.getInstance().get(Calendar.DAY_OF_MONTH);}/*** 构造函数: MMM DD YYYY (e8.14)* 根据月份的英文名称，日，年创建日期* @param monthLabel* @param day* @param year*/public Date (String monthLabel, int day, int year) {switch (monthLabel) {case "January":month = 1;break;case "Feburary":month = 2;break;case "March":month = 3;break;case "April":month = 4;break;case "May":month = 5;break;case "June":month = 6;break;case "July":month = 7;break;case "August":month = 8;break;case "Septemeber":month = 9;break;case "October":month = 10;break;case "November":month = 11;break;case "December":month = 12;break;}new Date (year, month, day);} /*** 构造函数: DDD YYYY (e8.14)* 根据一年中天数的序数（第n天）及年份创建日期* @param ddd* @param year*/public Date (int ddd, int year) {int[] accumulatedDaysNonLeapYear = {0,31,59,90,120,151,181,212,243,273,304,334,365}; //平年每月累积天数int[] accumulatedDaysLeapYear =    {0,31,60,91,121,152,182,213,244,274,305,335,366}; //闰年每月累积天数if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) {        //如果是闰年,使用闰年累计天数判断for (int i=12; i>0;i--) {if (ddd - accumulatedDaysLeapYear[i-1]>0) {month = i;day = ddd - accumulatedDaysLeapYear[i-1];break;}   }}else for (int i=12; i>0;i--) {                          //如果是闰年,使用闰年累计天数判断if (ddd - accumulatedDaysNonLeapYear[i-1]>0) {month = i;day = ddd - accumulatedDaysNonLeapYear[i-1];break;}    }   new Date (year, month, day);}   //return a String of the form year/month/daypublic String toString() {return String.format("%d年%d月%d日", year, month, day);}/*** 按照MM/DD/YYYY格式化输出 (e8.14)* @return*/public String toStringMDY() {return String.format("%02d/%02d/%d", month, day,year);}   /*** 按照MMM DD YYYY格式化输出 (e8.14)* @return*/public String toStringMMDY() {String mmm = "";switch (month) {case 1:mmm ="January";break;case 2:mmm ="Feburary";break;case 3:mmm ="March";break;case 4:mmm ="April";break;case 5:mmm ="May";break;case 6:mmm ="June";break;case 7:mmm ="July";break;case 8:mmm ="August";break;case 9:mmm ="September";break;case 10:mmm ="October";break;case 11:mmm ="November";break;case 12:mmm ="December";break;}return String.format("%s %02d %d", mmm, day,year);} /*** 按照DDD YYYY格式化输出 (ddd表示一年中的第n天，e8.14)* @return*/public String toStringDDDY() {int ddd =0;//已经过的整月份的天数为（按平年计算）for (int i=1;i<month;i++) {ddd += daysPerMonth[i];}//加上不足整月的天数ddd += day;//如果是闰年，且日期在2月29日之后，则天数加一if ((year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)) && ((month ==2 && day==29) ||month >=3))++ddd;return String.format("%03d %d", ddd, year);}//增加一天，2018年12月添加public static Date nextDay(int year, int month, int day) {
//数据校验逻辑（与构造函数相同）// check for year up to next year and later than 1918 //2018年12月添加if (year < 1918 || year > Calendar.getInstance().get(Calendar.YEAR) + 100) // 获取下一年的下100年throw new IllegalArgumentException("year (" + day + ") out-of-range. A year later than 1918 and up to next 100 years is expected.");// check if month in rangeif (month <= 0 || month > 12)throw new IllegalArgumentException("month (" + month + ") must be 1-12");// check if day in range for monthif (day <= 0 || (day > daysPerMonth[month] && !(month == 2 && day == 29)))throw new IllegalArgumentException("day (" + day + ") out-of-range for the specified month and year");// check for leap year if month is 2 and day is 29// 闰年判定规则：能被400整除，或，能被4整除但不能被100整除if (month == 2 && day == 29 && !(year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)))throw new IllegalArgumentException("day (" + day + ") out-of-range for the specified month and year");switch (month) {
//1月，3月，5月，7月，8月，10月和12月为小月，每月31天 case 1:case 3:case 5:case 7:case 8:case 10:case 12:if (day + 1 > 31) {day = 1;if (month + 1 > 12) {// 如果是12月31日，加一天后进入新的一年的第一天（元旦）month = 1;++year;} else++month;} else++day; // 非月末，日期直接加一break;
//4月，6月，9月和11月为小月，每月30天    case 4:case 6:case 9:case 11:if (day + 1 > 30) {day = 1;month = month + 1; // 进入下一月1号} else++day; // 非月末，日期直接加一break;case 2:// 2月既不是大月，也不是小月if (month == 2 && day == 29 && (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))) { // 闰年，2月为29天day = 1;month = month + 1; // 月份前进为3月份} else if (month == 2 && day == 28 && !(year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))) { // 平年，2月为28天day = 1;month = month + 1; // 月份前进为3月份} else++day; // 非月末，日期直接加一break;}return new Date(year, month, day);}//返回当前日期的下一天，2018年12月添加public Date nextDay() {int year = this.year;int month = this.month;int day = this.day;switch (month) {
//1月，3月，5月，7月，8月，10月和12月为小月，每月31天 case 1:case 3:case 5:case 7:case 8:case 10:case 12:if (day + 1 > 31) {day = 1;if (month + 1 > 12) {// 如果是12月31日，加一天后进入新的一年的第一天（元旦）month = 1;++year;} else++month;} else++day; // 非月末，日期直接加一break;
//4月，6月，9月和11月为小月，每月30天    case 4:case 6:case 9:case 11:if (day + 1 > 30) {day = 1;month = month + 1; // 进入下一月1号} else++day; // 非月末，日期直接加一break;case 2:// 2月既不是大月，也不是小月if (month == 2 && day == 29 && (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))) { // 闰年，2月为29天day = 1;month = month + 1; // 月份前进为3月份} else if (month == 2 && day == 28 && !(year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))) { // 平年，2月为28天day = 1;month = month + 1; // 月份前进为3月份} else++day; // 非月末，日期直接加一break;}return new Date(year, month, day);}/*** *  @return 月份*  @Date Jan 7, 2019, 12:59:45 AM*/
public int getMonth() {return this.month;
}} // end class Date

2) Emplyee类

//JHTP Exercise 10.12: Payroll System Modification
//by pandenghuang@163.com
/*** 10.12 (Payroll System Modification) Modify the payroll system of Figs.* 10.4–10.9 to include private instance variable birthDate in class Employee.* Use class Date of Fig. 8.7 to represent an employee’s birthday. Add get* methods to class Date. Assume that payroll is processed once per month.* Create an array of Employee variables to store references to the various* employee objects. In a loop, calculate the payroll for each Employee* (polymorphically), and add a $100.00 bonus to the person’s payroll amount if* the current month is the one in which the Employee’s birthday occurs.* * @author Pandenghuang@163.com**/// Fig. 10.4: Employee.java
// Employee abstract superclass.
/*** * @author Pandenghuang@163.com* @Date Jan 7, 2019, 12:42:40 AM**/
public abstract class Employee
{private final String firstName;private final String lastName;private final String socialSecurityNumber;private final Date birthDate;// constructor
/*** * @Date Jan 7, 2019, 12:29:21 AM* @param firstName* @param lastName* @param socialSecurityNumber* @param birthDate*/public Employee(String firstName, String lastName, Date birthDate,String socialSecurityNumber){this.firstName = firstName;                                    this.lastName = lastName;                                    this.socialSecurityNumber = socialSecurityNumber;  this.birthDate = birthDate;} // return first namepublic String getFirstName(){return firstName;} // return last namepublic String getLastName(){return lastName;} /*** * @Date Jan 7, 2019, 12:26:49 AM*  @return birthDate （生日）*/public Date getBirthDate(){return birthDate;} // return social security numberpublic String getSocialSecurityNumber(){return socialSecurityNumber;} // return String representation of Employee object@Overridepublic String toString(){return String.format("%s %s%n出生年月日: %s%nsocial security number: %s", getFirstName(), getLastName(), getBirthDate(),getSocialSecurityNumber());} // abstract method must be overridden by concrete subclassespublic abstract double earnings(); // no implementation here
} // end abstract class Employee

3) SalariedEmployee类

// Fig. 10.5: SalariedEmployee.java
// SalariedEmployee concrete class extends abstract class Employee.public class SalariedEmployee extends Employee
{private double weeklySalary;// constructor/*** * @Date Jan 7, 2019, 12:31:20 AM* @param firstName* @param lastName* @param socialSecurityNumber* @param weeklySalary* @param birthDate*/public SalariedEmployee(String firstName, String lastName, Date birthDate,String socialSecurityNumber, double weeklySalary){super(firstName, lastName,birthDate, socialSecurityNumber); if (weeklySalary < 0.0)throw new IllegalArgumentException("Weekly salary must be >= 0.0");this.weeklySalary = weeklySalary;} // set salarypublic void setWeeklySalary(double weeklySalary){if (weeklySalary < 0.0)throw new IllegalArgumentException("Weekly salary must be >= 0.0");this.weeklySalary = weeklySalary;} // return salarypublic double getWeeklySalary(){return weeklySalary;} // calculate earnings; override abstract method earnings in Employee@Override                                                           public double earnings()                                            {                                                                   return getWeeklySalary();                                        }                                             // return String representation of SalariedEmployee object   @Override                                                    public String toString()                                     {                                                            return String.format("salaried employee: %s%n%s: $%,.2f",super.toString(), "weekly salary", getWeeklySalary());}
} // end class SalariedEmployee

4) HourlyEmployee类

// Fig. 10.6: HourlyEmployee.java
// HourlyEmployee class extends Employee.public class HourlyEmployee extends Employee
{private double wage; // wage per hourprivate double hours; // hours worked for week// constructor/*** * @Date Jan 7, 2019, 12:31:40 AM* @param firstName* @param lastName* @param socialSecurityNumber* @param wage* @param hours* @param birthDate*/public HourlyEmployee(String firstName, String lastName,Date birthDate,String socialSecurityNumber, double wage, double hours){super(firstName, lastName,birthDate, socialSecurityNumber);if (wage < 0.0) // validate wagethrow new IllegalArgumentException("Hourly wage must be >= 0.0");if ((hours < 0.0) || (hours > 168.0)) // validate hoursthrow new IllegalArgumentException("Hours worked must be >= 0.0 and <= 168.0");this.wage = wage;this.hours = hours;} // set wagepublic void setWage(double wage){if (wage < 0.0) // validate wagethrow new IllegalArgumentException("Hourly wage must be >= 0.0");this.wage = wage;} // return wagepublic double getWage(){return wage;} // set hours workedpublic void setHours(double hours){if ((hours < 0.0) || (hours > 168.0)) // validate hoursthrow new IllegalArgumentException("Hours worked must be >= 0.0 and <= 168.0");this.hours = hours;} // return hours workedpublic double getHours(){return hours;} // calculate earnings; override abstract method earnings in Employee@Override                                                           public double earnings()                                            {                                                                   if (getHours() <= 40) // no overtime                           return getWage() * getHours();                                else                                                             return 40 * getWage() + (getHours() - 40) * getWage() * 1.5;}                                          // return String representation of HourlyEmployee object              @Override                                                             public String toString()                                              {                                                                     return String.format("hourly employee: %s%n%s: $%,.2f; %s: %,.2f",super.toString(), "hourly wage", getWage(),                     "hours worked", getHours());                                   }
} // end class HourlyEmployee

5) CommissionEmployee类

// Fig. 10.7: CommissionEmployee.java
// CommissionEmployee class extends Employee.public class CommissionEmployee extends Employee
{private double grossSales; // gross weekly salesprivate double commissionRate; // commission percentage// constructor/*** * @Date Jan 7, 2019, 12:31:03 AM* @param firstName* @param lastName* @param socialSecurityNumber* @param birthDate* @param grossSales* @param commissionRate*/public CommissionEmployee(String firstName, String lastName, Date birthDate,String socialSecurityNumber,  double grossSales, double commissionRate){super(firstName, lastName, birthDate,socialSecurityNumber);if (commissionRate <= 0.0 || commissionRate >= 1.0) // validate throw new IllegalArgumentException("Commission rate must be > 0.0 and < 1.0");if (grossSales < 0.0) // validatethrow new IllegalArgumentException("Gross sales must be >= 0.0");this.grossSales = grossSales;this.commissionRate = commissionRate;} // set gross sales amountpublic void setGrossSales(double grossSales){if (grossSales < 0.0) // validatethrow new IllegalArgumentException("Gross sales must be >= 0.0");this.grossSales = grossSales;} // return gross sales amountpublic double getGrossSales(){return grossSales;} // set commission ratepublic void setCommissionRate(double commissionRate){if (commissionRate <= 0.0 || commissionRate >= 1.0) // validatethrow new IllegalArgumentException("Commission rate must be > 0.0 and < 1.0");this.commissionRate = commissionRate;} // return commission ratepublic double getCommissionRate(){return commissionRate;} // calculate earnings; override abstract method earnings in Employee@Override                                                           public double earnings()                                            {                                                                   return getCommissionRate() * getGrossSales();                    }                                             // return String representation of CommissionEmployee object@Override                                                   public String toString()                                    {                                                           return String.format("%s: %s%n%s: $%,.2f; %s: %.2f",    "commission employee", super.toString(),              "gross sales", getGrossSales(),                       "commission rate", getCommissionRate());             }
} // end class CommissionEmployee

6) BasePlusCommissionEmployee类

// Fig. 10.8: BasePlusCommissionEmployee.java
// BasePlusCommissionEmployee class extends CommissionEmployee.public class BasePlusCommissionEmployee extends CommissionEmployee
{private double baseSalary; // base salary per week// constructorpublic BasePlusCommissionEmployee(String firstName, String lastName, Date birthDate,String socialSecurityNumber,  double grossSales,double commissionRate, double baseSalary){super(firstName, lastName, birthDate,socialSecurityNumber, grossSales, commissionRate);if (baseSalary < 0.0) // validate baseSalary                  throw new IllegalArgumentException("Base salary must be >= 0.0");this.baseSalary = baseSalary;                }// set base salarypublic void setBaseSalary(double baseSalary){if (baseSalary < 0.0) // validate baseSalary                  throw new IllegalArgumentException("Base salary must be >= 0.0");this.baseSalary = baseSalary;                } // return base salarypublic double getBaseSalary(){return baseSalary;}// calculate earnings; override method earnings in CommissionEmployee@Override                                                            public double earnings()                                             {                                                                    return getBaseSalary() + super.earnings();                        } // return String representation of BasePlusCommissionEmployee object@Override                                                           public String toString()                                            {                                                                   return String.format("%s %s; %s: $%,.2f",                       "base-salaried", super.toString(),                            "base salary", getBaseSalary());                             }
} // end class BasePlusCommissionEmployee

2. 测试类

// Fig. 10.9: PayrollSystemTest.java
// Employee hierarchy test program.//JHTP Exercise 10.12: Payroll System Modification
//by pandenghuang@163.comimport java.util.Calendar;/**
* 10.12 (Payroll System Modification) Modify the payroll system of Figs.
* 10.4–10.9 to include private instance variable birthDate in class Employee.
* Use class Date of Fig. 8.7 to represent an employee’s birthday. Add get
* methods to class Date. Assume that payroll is processed once per month.
* Create an array of Employee variables to store references to the various
* employee objects. In a loop, calculate the payroll for each Employee
* (polymorphically), and add a $100.00 bonus to the person’s payroll amount if
* the current month is the one in which the Employee’s birthday occurs.
* @author Pandenghuang@163.com
* @Date Jan 7, 2019, 12:40:32 AM
*
*/
public class PayrollSystemTest
{public static void main(String[] args) {// create subclass objectsSalariedEmployee salariedEmployee = new SalariedEmployee("John", "Smith", new Date(1980,10,1),"111-11-1111", 800.00);HourlyEmployee hourlyEmployee = new HourlyEmployee("Karen", "Price", new Date(1970,1,31),"222-22-2222", 16.75, 40);CommissionEmployee commissionEmployee = new CommissionEmployee("Sue", "Jones", new Date(1990,1,18),"333-33-3333", 10000, .06);BasePlusCommissionEmployee basePlusCommissionEmployee = new BasePlusCommissionEmployee("Bob", "Lewis", new Date(1992,5,20),"444-44-4444", 5000, .04, 300);System.out.println("Employees processed individually:");System.out.printf("%n%s%n%s: $%,.2f%n%n", salariedEmployee, "earned", salariedEmployee.earnings());System.out.printf("%s%n%s: $%,.2f%n%n",hourlyEmployee, "earned", hourlyEmployee.earnings());System.out.printf("%s%n%s: $%,.2f%n%n",commissionEmployee, "earned", commissionEmployee.earnings());System.out.printf("%s%n%s: $%,.2f%n%n", basePlusCommissionEmployee, "earned", basePlusCommissionEmployee.earnings());// create four-element Employee arrayEmployee[] employees = new Employee[4]; // initialize array with Employeesemployees[0] = salariedEmployee;employees[1] = hourlyEmployee;employees[2] = commissionEmployee; employees[3] = basePlusCommissionEmployee;System.out.printf("Employees processed polymorphically:%n%n");// generically process each element in array employeesfor (Employee currentEmployee : employees) {System.out.println(currentEmployee); // invokes toString// determine whether element is a BasePlusCommissionEmployeeif (currentEmployee instanceof BasePlusCommissionEmployee) {// downcast Employee reference to // BasePlusCommissionEmployee referenceBasePlusCommissionEmployee employee = (BasePlusCommissionEmployee) currentEmployee;employee.setBaseSalary(1.10 * employee.getBaseSalary());System.out.printf("new base salary with 10%% increase is: $%,.2f%n",employee.getBaseSalary());} // 如果遇到员工生日在当月，工资总额加100 (2019/01/07)if (currentEmployee.getBirthDate().getMonth() == Calendar.getInstance().get(Calendar.MONTH)+1) System.out.printf("earned $%,.2f%n%n", currentEmployee.earnings()+100);elseSystem.out.printf("earned $%,.2f%n%n", currentEmployee.earnings()); }// get type name of each object in employees arrayfor (int j = 0; j < employees.length; j++)System.out.printf("Employee %d is a %s%n", j, employees[j].getClass().getName()); } // end main
} // end class PayrollSystemTest