# 2019/0514/Java\_靜態類別+繼承特性 \#Java類別&物件 ### ##Static 類別成員 呼叫 ex: Math.PI 不能存取非Static類別成員 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqxgLVJ9xIss1xVFsG%2Fimage.png?alt=media\&token=74c07ad6-6904-44c5-b165-fbef895c11d3) This這個參照是屬於動態方法 new 初始化物件 所以 static無法使用 static 屬於編譯時就存在了 new則是new之後才存在 #### ###目的 展示動態物件內靜態屬性值 靜態方法只能讀取靜態參數值 動態靜態無法互相呼叫參照 使用靜態方法方式 動態方法new完後應該靜態參數就可以存取 但還是會報錯應該要在 static方法內存取 #### ### EmployeeS ``` package com.example.java; public class EmployeeS { private static int count = 0; // number of Employees created private String firstName; private String lastName; public Date birthDate; public Date hireDate; public EmployeeS(String firstName, String lastName,Date birthDate, Date hireDate) { this.firstName = firstName; this.lastName = lastName; this.birthDate = birthDate; this.hireDate = hireDate; ++count; System.out.printf("EmployeeS 物件建立成功 : %s %s; EmployeeS物件數量 = %d%n", firstName, lastName, count); } public String getFirstName() { String strTemp = String.valueOf(this.count); return firstName+strTemp; } public String getLastName() { return lastName; } public static int getCount() { // String s1= firstName; // String s2; // s2 = getFirstName(); return count; } public String toString() { return String.format("%s,%s-雇用日期: %s-出生日期: %s", lastName, firstName, hireDate, birthDate); } } ``` ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Leqy21icJ9rfKUhJLRn%2Fimage.png?alt=media\&token=6531a8e1-fd00-4147-b23b-c142a415a140) #### ### EmployeeSTest ``` package com.example.java; public class EmployeeSTest { public static void main(String[] args) { // TODO 自動產生的方法 Stub System.out.printf("新增員工前， EmployeeS物件數量: %d%n", EmployeeS.getCount()); Date birth = new Date(7, 24, 2005); Date hire = new Date(3, 12, 2016); EmployeeS e1 = new EmployeeS("李", "連杰", birth, hire); EmployeeS e2 = new EmployeeS("甄", "子丹", birth, hire); System.out.printf("%n新增員工後， EmployeeS物件數量:%n"); System.out.printf("呼叫 EmployeeS.getCount(): %d%n", EmployeeS.getCount()); System.out.printf("%n員工 1: %s %s%n員工2: %s %s%n", e1.getFirstName(), e1.getLastName(), e2.getFirstName(), e2.getLastName()); System.out.println(e1); } } ``` ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqyBSE3wM7r2EJBy5y%2Fimage.png?alt=media\&token=fa9d1fce-e965-4607-83f2-f59a18c824f2) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqyDxCG-Swm7ZLDHUh%2Fimage.png?alt=media\&token=bfa6c0fc-d821-4130-b97b-062a08bace83) ### ##靜態類別匯入 Import 在 c#就是using ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqyNsenzk8kUPcC9Wm%2Fimage.png?alt=media\&token=28b00342-6601-493b-a1d6-a28f6e0f5a6b) #### ### StaticImportTest.java ``` package com.example.java; import static java.lang.Math.*; //import static java.lang.Math.sqrt; //import static java.lang.Math.ceil; public class StaticImportTest { public static void main(String[] args) { // TODO 自動產生的方法 Stub System.out.printf("呼叫 Math.sqrt,sqrt(900.0) = %.1f%n", sqrt(900.0)); System.out.printf("呼叫 Math.ceil,ceil(-9.8) = %.1f%n", ceil(-9.8)); System.out.printf("呼叫 Math.E,E = %f%n", java.lang.Math.E); System.out.printf("呼叫 Math.PI,PI = %f%n", java.lang.Math.PI); } } ``` ## #繼承 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Leqy_ryFVikvTbuts25%2Fimage.png?alt=media\&token=baa8f779-3fc3-419d-a611-1a17cd031448) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqyfYG4ip59BJF0MCj%2Fimage.png?alt=media\&token=dadc3603-e364-4159-90e5-0100cb75f671) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqyvyelsfxfuDp4C_x%2Fimage.png?alt=media\&token=0dc38df6-c920-479e-bd26-9db2fde20765) #### ##特殊化specialization ### ##直接間接父類別 #### ##直接間接父類別direct superclass 上層(一代 (其實有祖類別 #### ##間接父類別 indirect superclass #### java元祖類別為 object #### Java只支援單一繼承 跟c++不一樣 sigle inheritance ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Leqz6Fc9GRjqxlSqE3H%2Fimage.png?alt=media\&token=7105cb80-fcc5-4d00-b7c9-f4fe8d2188be) #### ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqzEPlDkhda9tVYub0%2Fimage.png?alt=media\&token=5181e2ec-668e-4b27-a2d7-2a99c4094088) ### ##類別在使用上有兩種狀態 Is a relationship #### ###繼承 Has a relationship #### ###複合 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqzKpS5WyJbImAVJKT%2Fimage.png?alt=media\&token=74823042-a2d9-4e2b-893c-b3f040deab1a) 越子代特徵會越明顯越清楚跟界門綱目科屬種很像 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqzPawZB9FSHQUdJgI%2Fimage.png?alt=media\&token=182ae07e-1699-4f86-9b63-d641b7e58690) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqzRrw-2QP04Jx93tf%2Fimage.png?alt=media\&token=94902e20-535c-4c83-85ac-b7c69b28ef42) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Leqzc_65ziY0Js4fULg%2Fimage.png?alt=media\&token=9c4804fb-c696-4221-8ba4-46f66d05bb51) ### ##向上轉型 一般化往上移 ( 通用 特性化往下移 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Leqzi-cnSL7EpEJJidS%2Fimage.png?alt=media\&token=099629f9-12b6-4465-a49b-96ca20f0fef1) ### ##繼承-存取權 Private 必須要在同一個 class 裡面 Protected 要有繼承關係或同個packge ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-LeqzncAy7JgDCKuAx-A%2Fimage.png?alt=media\&token=515e2fca-cb43-45ff-81ed-e599c957e699) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Leqzsov1Q6qRiZo5lFE%2Fimage.png?alt=media\&token=71f3b3cc-a652-40a0-9121-52e45cf67e14) #### ##Entends 繼承 #### ###CommissionEmployee.java ``` package com.example.java; public class CommissionEmployee extends Object{ private final String firstName; private final String lastName; private final String idNumber; private double grossSales; private double commissionRate; // 佣金，抽庸的比例 public CommissionEmployee(String firstName, String lastName, String idNumber, double grossSales, double commissionRate) { if (grossSales < 0.0) throw new IllegalArgumentException("銷售金額必須 >= 0.0"); if (commissionRate <= 0.0 || commissionRate >= 1.0) throw new IllegalArgumentException("佣金比例必須 > 0.0 and < 1.0"); this.firstName = firstName; this.lastName = lastName; this.idNumber = idNumber; this.grossSales = grossSales; this.commissionRate = commissionRate; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public String getIdNumber() { return idNumber; } public void setGrossSales(double grossSales) { if (grossSales < 0.0) throw new IllegalArgumentException("銷售金額必須 >= 0.0"); this.grossSales = grossSales; } public double getGrossSales() { return grossSales; } public void setCommissionRate(double commissionRate) { if (commissionRate <= 0.0 || commissionRate >= 1.0) throw new IllegalArgumentException("Commission rate must be > 0.0 and < 1.0"); this.commissionRate = commissionRate; } public double getCommissionRate() { return commissionRate; } public double earnings() { return commissionRate * grossSales; } @Override public String toString() { return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f %n%s: %.2f" , "領佣金的員工姓名", firstName, lastName, "身分證字號", idNumber, "每周銷售金額", grossSales, "佣金比例", commissionRate, "薪資",this.earnings()); } } ``` ### ##在不夠熟悉時 通常是實作兩個子類別最後再把相同之處往上搬制做父類別 操控CommissionEmployee類別鑄造物件並操控物件進行方法 但其實是準備跟Employee類別做一般化的父類別 #### ### CommissionEmployeeTest.java ``` package com.example.java; public class CommissionEmployeeTest { public static void main(String[] args) { // TODO 自動產生的方法 Stub CommissionEmployee employee01 = new CommissionEmployee("劉", "德華", "A123456789", 10000, .06); CommissionEmployee employee02 = new CommissionEmployee("陳", "立農", "A123456789", 5000, .1); System.out.println("以下呼叫 Get Method 取回員工資料:"); System.out.printf("%n%s %s%n", "姓:", employee01.getFirstName()); System.out.printf("%s %s%n", "名:", employee01.getLastName()); System.out.printf("%s %s%n", "身分證字號:", employee01.getIdNumber()); System.out.printf("%s %.2f%n", "銷售金額:", employee01.getGrossSales()); System.out.printf("%s %.2f%n", "佣金比例:", employee01.getCommissionRate()); employee01.setGrossSales(15000); employee01.setCommissionRate(.65); System.out.printf("%n%s:%n%n%s%n", "更新員工資料後，呼叫 toString Method 取回員工資料:", employee01); System.out.printf("%n%s:%n%n%s%n", "第二位員工資料", employee02.toString()); } } ``` ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-G34I4fFpvcc8OxB%2Fimage.png?alt=media\&token=9f1f0c77-b918-437a-bb95-839984bdb9a4) ### ##建構子不會被繼承 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-M_GhML68V1F-bQ1%2Fimage.png?alt=media\&token=43f9fff2-5e21-49dd-817f-0782dfd2490d) ### ##不標記@Override也會複寫但最好要加上去 {% embed url="" %} ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-TJ9usOUWuldLk7N%2Fimage.png?alt=media\&token=373b81fa-dc67-476f-9a27-d2cb92356f99) {% embed url="" %} 在實作一個子類別 不一樣的地方只有紅色的地方 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-_XmNSb3HarAWzeB%2Fimage.png?alt=media\&token=fbc1664e-38dd-4f17-912c-8b46302ad381) #### ###BasePlusCommissionEmployee.java #### ##減少重複程式碼 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-h9Z3Va_gbumWpoK%2Fimage.png?alt=media\&token=e3b3d1a7-a69a-430c-9988-76e257e07f93) 建構子 方法 程式碼幾乎一樣 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-lKg3nlOgt4XXwhu%2Fimage.png?alt=media\&token=dc762862-c6ef-40c6-8cc0-167bd7333633) #### ##防止錯誤 ( 重點為第三點 維護困難 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-pk-aUHxwH-uWcHw%2Fimage.png?alt=media\&token=0e5fded3-6813-4b09-a4aa-58e862e46d64) ### ##繼承的使用 設計繼承架構 從兩個都是繼承object轉成其中一個為父類別， (BasePlusCommissionEmployee、CommissionEmployee ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler-wUl7v08x2v3lVbQ%2Fimage.png?alt=media\&token=eb098092-6cf4-498a-8eb8-25a3e229e5d4) ### #子類別呼叫父類別建構式 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler01v2g37sB8G7IESd%2Fimage.png?alt=media\&token=31b736c5-6ff3-46ee-ba6b-3aee3a795fb3) ### ##初始化new父輩實體變數(參數) super ， c#裡面是base {% embed url="" %} #### ###如果沒有寫參數就會自動呼叫沒有參數的版本 #### ###super(參數, 參數, 參數…) super(firstName, lastName, socialSecurityNumber, ◦ grossSales, commissionRate); #### ###Super呼叫方法也可以間接取到父輩的參數 super.getGrossSales #### ###或是把參數從私有改為保護或公有 #### ###類別設計好了要在新增一個檔案test做測試 #### ###熟了的話可以直接從規格書知道那些要寫在父類(一般化)別那些要寫在子(特殊化)，架構邏輯要清楚 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler0J3o_YoKCVXbj-oa%2Fimage.png?alt=media\&token=fd39791d-a392-45a0-9db9-a53b956b3d58) #### ###CommissionEmployeeExtV1 ( 父類別 繼承實作 ``` package com.example.java; public class CommissionEmployeeExtV1 extends Object{ private final String firstName; private final String lastName; private final String idNumber; private double grossSales; private double commissionRate; // 佣金，抽庸的比例 public CommissionEmployeeExtV1(String firstName, String lastName, String idNumber, double grossSales, double commissionRate) { if (grossSales < 0.0) throw new IllegalArgumentException("銷售金額必須 >= 0.0"); if (commissionRate <= 0.0 || commissionRate >= 1.0) throw new IllegalArgumentException("佣金比例必須 > 0.0 and < 1.0"); this.firstName = firstName; this.lastName = lastName; this.idNumber = idNumber; this.grossSales = grossSales; this.commissionRate = commissionRate; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public String getIdNumber() { return idNumber; } public void setGrossSales(double grossSales) { if (grossSales < 0.0) throw new IllegalArgumentException("銷售金額必須 >= 0.0"); this.grossSales = grossSales; } public double getGrossSales() { return grossSales; } public void setCommissionRate(double commissionRate) { if (commissionRate <= 0.0 || commissionRate >= 1.0) throw new IllegalArgumentException("佣金比例必須 > 0.0 and < 1.0"); this.commissionRate = commissionRate; } public double getCommissionRate() { return commissionRate; } public double earnings() { return commissionRate * grossSales; } @Override public String toString() { return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f %n%s: %.2f" , "領佣金的員工姓名", firstName, lastName, "身分證字號", idNumber, "每周銷售金額", grossSales, "佣金比例", commissionRate, "薪資",this.earnings()); } } ``` #### ###BasePlusCommissionEmployeeExtV1 ( 子類別 繼承實作 ``` package com.example.java; public class BasePlusCommissionEmployeeExtV1 extends CommissionEmployeeExtV1{ private double baseSalary; //底薪 public BasePlusCommissionEmployeeExtV1(String firstName, String lastName, String idNumber, double grossSales, double commissionRate,double baseSalary) { super(firstName,lastName,idNumber,grossSales,commissionRate); if (baseSalary < 0.0) throw new IllegalArgumentException("底薪金額必須 >= 0.0"); this.baseSalary = baseSalary; } public void setBaseSalary(double baseSalary) { if (baseSalary < 0.0) throw new IllegalArgumentException("底薪金額必須 >= 0.0"); this.baseSalary = baseSalary; } public double getBaseSalary() { return baseSalary; } @Override public double earnings() { return baseSalary + (super.getCommissionRate() * super.getGrossSales()); } @Override public String toString() { return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f %n%s: %.2f" , "領佣金的員工姓名", super.getFirstName(), super.getLastName(), "身分證字號", super.getIdNumber(), "每周銷售金額", getGrossSales(), "佣金比例", getCommissionRate(), "底薪金額", baseSalary); } } ``` #### ### BasePlusCommissionEmployeeExtV1Test #### ( 現在這個階段都在做類別所以檔案內不會有print必須要用 test檔案內 類別的物件操控做顯示 ``` package com.example.java; public class BasePlusCommissionEmployeeExtV1Test { public static void main(String[] args) { // TODO 自動產生的方法 Stub BasePlusCommissionEmployeeExtV1 employee01 = new BasePlusCommissionEmployeeExtV1("劉", "德華", "A123456789", 10000, .06,1000); CommissionEmployeeExtV1 employee02 = new CommissionEmployeeExtV1("陳", "立農", "A123456789", 5000, .1); System.out.println("以下呼叫 Get Method 取回員工資料:"); System.out.printf("%n%s %s%n", "姓:", employee01.getFirstName()); System.out.printf("%s %s%n", "名:", employee01.getLastName()); System.out.printf("%s %s%n", "身分證字號:", employee01.getIdNumber()); System.out.printf("%s %.2f%n", "銷售金額:", employee01.getGrossSales()); System.out.printf("%s %.2f%n", "佣金比例:", employee01.getCommissionRate()); System.out.printf("%s %.2f%n", "底薪金額:", employee01.getBaseSalary()); employee01.setGrossSales(15000); employee01.setCommissionRate(0.1); employee01.setBaseSalary(2000); System.out.printf("%n%s:%n%n%s%n", "更新員工資料後，呼叫 toString Method 取回員工資料:", employee01); System.out.printf("總薪資:"+String.valueOf(employee01.earnings())); System.out.println("\n\n領獎金員工資料:"); System.out.printf("%n%s:%n%n%s%n", "呼叫 toString Method 取回員工資料:", employee02); } } ``` ### ##繼承重點 經過一系列以上的操作可以看到繼承後的程式碼少了非常少 (重複的都在父類別了 而且修改只要改源頭不需要一個檔案一個檔案改 接著 V2版本 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler0Pgb_FnNPfgnlqlj%2Fimage.png?alt=media\&token=863a116d-11d5-49c4-bc87-112194ac74ef) ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler0R_Jcdya4PZ_30oI%2Fimage.png?alt=media\&token=caa4dc0a-b39f-4e5a-b3bb-44135102371f) 保留封裝特性但同時又能存取父類別參數 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler0Vieosa_mnZiZ6Ut%2Fimage.png?alt=media\&token=e8708655-8706-477b-a690-5ed3a5acfbb9) 孫代也更好的可以存取參數 ### ##參數使用保護繼承的問題 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler0_0r_qAIEaPQDX-8%2Fimage.png?alt=media\&token=4f4620ee-701a-4d5f-8490-25c290ad80ce) #### ###參數變成無效直沒經過驗證(因為驗證寫在父輩 ![](https://1902678905-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LVJQfuBXyvHwCd1Nadk%2F-LeqxTZq4JAWWPrB6inP%2F-Ler0dEMXBcm2g3MySMv%2Fimage.png?alt=media\&token=28fd1c26-f5d4-4a24-8030-0464f10ae72a) #### ###修改父類別的內容變成不會影響到子類別 #### ###CommissionEmployeeExtV2 ``` package com.example.java; public class CommissionEmployeeExtV2 extends Object{ protected final String firstName; protected final String lastName; protected final String idNumber; protected double grossSales; protected double commissionRate; // 佣金，抽庸的比例 public CommissionEmployeeExtV2(String firstName, String lastName, String idNumber, double grossSales, double commissionRate) { if (grossSales < 0.0) throw new IllegalArgumentException("銷售金額必須 >= 0.0"); if (commissionRate <= 0.0 || commissionRate >= 1.0) throw new IllegalArgumentException("佣金比例必須 > 0.0 and < 1.0"); this.firstName = firstName; this.lastName = lastName; this.idNumber = idNumber; this.grossSales = grossSales; this.commissionRate = commissionRate; } public String getFirstName() { return firstName; } public String getLastName() { return lastName; } public String getIdNumber() { return idNumber; } public void setGrossSales(double grossSales) { if (grossSales < 0.0) throw new IllegalArgumentException("銷售金額必須 >= 0.0"); this.grossSales = grossSales; } public double getGrossSales() { return grossSales; } public void setCommissionRate(double commissionRate) { if (commissionRate <= 0.0 || commissionRate >= 1.0) throw new IllegalArgumentException("佣金比例必須 > 0.0 and < 1.0"); this.commissionRate = commissionRate; } public double getCommissionRate() { return commissionRate; } public double earnings() { return commissionRate * grossSales; } @Override public String toString() { return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f %n%s: %.2f" , "領佣金的員工姓名", firstName, lastName, "身分證字號", idNumber, "每周銷售金額", grossSales, "佣金比例", commissionRate, "薪資",this.earnings()); } } ``` #### ###BasePlusCommissionEmployeeExtV2 ``` package com.example.java; public class BasePlusCommissionEmployeeExtV2 extends CommissionEmployeeExtV2 { protected double baseSalary; // 底薪 public BasePlusCommissionEmployeeExtV2(String firstName, String lastName, String idNumber, double grossSales,double commissionRate, double baseSalary) { super(firstName, lastName, idNumber, grossSales, commissionRate); if (baseSalary < 0.0) throw new IllegalArgumentException("底薪金額必須 >= 0.0"); this.baseSalary = baseSalary; } public void setBaseSalary(double baseSalary) { if (baseSalary < 0.0) throw new IllegalArgumentException("底薪金額必須 >= 0.0"); this.baseSalary = baseSalary; } public double getBaseSalary() { return baseSalary; } @Override public double earnings() { grossSales = -5000.0; return baseSalary + (commissionRate * grossSales); } @Override public String toString() { return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f %n%s: %.2f" , "領佣金的員工姓名", firstName, lastName, "身分證字號", idNumber, "每周銷售金額", grossSales, "佣金比例", commissionRate, "底薪金額", baseSalary); } } ``` #### ###BasePlusCommissionEmployeeExtV2Test ``` package com.example.java; public class BasePlusCommissionEmployeeExtV2Test { public static void main(String[] args) { // TODO 自動產生的方法 Stub BasePlusCommissionEmployeeExtV2 employee01 = new BasePlusCommissionEmployeeExtV2("劉", "德華", "A123456789", 10000, .06,1000); CommissionEmployeeExtV2 employee02 = new CommissionEmployeeExtV2("陳", "立農", "A123456789", 5000, .1); System.out.println("以下呼叫 Get Method 取回員工資料:"); System.out.printf("%n%s %s%n", "姓:", employee01.getFirstName()); System.out.printf("%s %s%n", "名:", employee01.getLastName()); System.out.printf("%s %s%n", "身分證字號:", employee01.getIdNumber()); System.out.printf("%s %.2f%n", "銷售金額:", employee01.getGrossSales()); System.out.printf("%s %.2f%n", "佣金比例:", employee01.getCommissionRate()); System.out.printf("%s %.2f%n", "底薪金額:", employee01.getBaseSalary()); employee01.setGrossSales(15000); employee01.setCommissionRate(0.1); employee01.setBaseSalary(2000); System.out.printf("%n%s:%n%n%s%n", "更新員工資料後，呼叫 toString Method 取回員工資料:", employee01); System.out.printf("總薪資:"+String.valueOf(employee01.earnings())); System.out.println("\n\n領獎金員工資料:"); System.out.printf("%n%s:%n%n%s%n", "呼叫 toString Method 取回員工資料:", employee02); } } ```