Question

对于这个程序，到目前为止我所写的内容在下面的代码中。我被卡住了。任何提示/帮助将不胜感激。

给定UML类图和TestApp类，生成满足以下要求的工作系统：

使用toString实现Department类并等于覆盖。如果名称和建筑物编号都匹配，则两个部门对象相等。

使用toString和equals覆盖创建一个抽象的Employee类。如果两个抽象员工在同一个部门，则被认为是相同的。

实现具有hourlySalary的Consultant类。如果两个顾问的费率相同（用便士），则两个顾问是平等的。

实施SalariedEmployee类。如果薪水员工在同一个部门并且薪水相同（以便士为单位），那么他们是平等的。

按照TestApp类中的TODO说明从输入txt文件中读取部门并测试系统。

Ouput should be:

Executive 100
Research 112
Engineering 115
Production 120
Accounting 122
Executive 100(100) Steve Jobs $1000000.00
Research 112(200) Bill Joy $300000.00 
Engineering 115(300) James Gosling $300000.00 
Production 120(1100) Craig McClanahan $250.00    
Accounting 122(400) Kevin Malone $51567.00  
Research 112

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class TestApp {

public static void main(String[] args) {
    ArrayList<Department> depts = 
        readDepartmentsFromFile("depts.txt");
    displayDepartments(depts);

    ArrayList<Employee> company = new ArrayList<>();
    populateEmployeeArray(company, depts);

    // TODO: Display everyone's pay w/o referring to the 
    // subclasses (i.e., using Employee only)

    // TODO: Display all departments that are equal to this one:
    Department d1 = new Department("Research", 112);

    // TODO: Display all departments that are equal to this one:
    Department d2 = new Department("Accounting", 50);

}

private static void displayDepartments(ArrayList<Department> list) {
    // TODO: Display the list to std error (NOT standard output)
}

private static ArrayList<Department> readDepartmentsFromFile(String filename) {
    ArrayList<Department> list = new ArrayList<>();
    // TODO: Use a Scanner to read the input file depts.txt
    // and create one Department object per line in the file.
    // Add all objects to the list.
    // Be sure to close the scanner object using a finally block.
    // Handle possible execptions by producing a nice error 
    // along with the execption's message to standard error 
    // (NOT standard output).
    return list;
}

public static void populateEmployeeArray(ArrayList<Employee> array, 
        ArrayList<Department> departments) {
    SalariedEmployee exec = new SalariedEmployee(100, "Steve", 
            "Jobs", departments.get(0), 100000000);
    SalariedEmployee architect = new SalariedEmployee(200, "Bill", 
            "Joy", departments.get(1), 30000000);
    SalariedEmployee engineer = new SalariedEmployee(300, "James", 
            "Gosling", departments.get(2), 30000000);
    Consultant consultant = new Consultant(1100, "Craig", 
            "McClanahan", departments.get(3), 25000);
    SalariedEmployee accountant = new SalariedEmployee(400, 
            "Kevin", "Malone", departments.get(4), 5156700);

    array.add(exec);
    array.add(architect);
    array.add(engineer);
    array.add(consultant);
    array.add(accountant);
}

}

*更新了TestApp

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class TestApp {

public static void main(String[] args) {
    ArrayList<Department> depts = 
        readDepartmentsFromFile("depts.txt");
    displayDepartments(depts);

    ArrayList<Employee> company = new ArrayList<>();
    populateEmployeeArray(company, depts);

    // TODO: Display everyone's pay w/o referring to the 
    // subclasses (i.e., using Employee only)
    for (Employee employee : company){
        System.out.println(employee);
    }

    // TODO: Display all departments that are equal to this one:
    Department d1 = new Department("Research", 112);
    for (Department department : depts)
        if(department.equals(d1)){
            System.out.println(department);
        }

    // TODO: Display all departments that are equal to this one:
    Department d2 = new Department("Accounting", 50);
    for(Department department : depts){
        if(department.equals(d2)){
            System.out.println(department);
        }
    }

}

private static void displayDepartments(ArrayList<Department> list) {
    // TODO: Display the list to std error (NOT standard output)
    System.err.println(department.toString());
}

private static ArrayList<Department> readDepartmentsFromFile(String filename) {
    ArrayList<Department> list = new ArrayList<>();
    // TODO: Use a Scanner to read the input file depts.txt
    // and create one Department object per line in the file.
    // Add all objects to the list.
    // Be sure to close the scanner object using a finally block.
    // Handle possible execptions by producing a nice error 
    // along with the execption's message to standard error 
    // (NOT standard output).
    File aFile = new File(filename);
    System.out.println(aFile.exists());
    Scanner sc = null;
    if (aFile.exists())
        try{
            sc = new Scanner(aFile);
            while(sc.hasNext()) {
                String deptName = sc.next();
                int buildNum = sc.nextInt();
                Department mallory = new Department(deptName, buildNum);
                list.add(mallory);

                }
            }
    catch(FileNotFoundException exec) {
        System.out.println(exec.getMessage());
    }
    finally {
        sc.close();
    }
    return list;
}

public static void populateEmployeeArray(ArrayList<Employee> array, 
        ArrayList<Department> departments) {
    SalariedEmployee exec = new SalariedEmployee(100, "Steve", 
            "Jobs", departments.get(0), 100000000);
    SalariedEmployee architect = new SalariedEmployee(200, "Bill", 
            "Joy", departments.get(1), 30000000);
    SalariedEmployee engineer = new SalariedEmployee(300, "James", 
            "Gosling", departments.get(2), 30000000);
    Consultant consultant = new Consultant(1100, "Craig", 
            "McClanahan", departments.get(3), 25000);
    SalariedEmployee accountant = new SalariedEmployee(400, 
            "Kevin", "Malone", departments.get(4), 5156700);

    array.add(exec);
    array.add(architect);
    array.add(engineer);
    array.add(consultant);
    array.add(accountant);
}

}

TEXT FILE - 
depts.txt - 
Executive 100
Research 112
Engineering 115
Production 120
Accounting 122

Answer 1

在将任何内容放入ArrayList之前，您已在部门上调用get(0)和get(1)。解决方案：不要这样做！填写ArrayList，在知道该索引存在某些内容之前，不要再调用get(...)。

populateEmployeeArray(company, depts);  // passed into method

以下是填充depts ArrayList：

的方法

// you might need a bit more code in here!!!!  The // TODO: means do it :)
private static ArrayList<Department> readDepartmentsFromFile(String filename) {
  ArrayList<Department> list = new ArrayList<>();
  // TODO: Use a Scanner to read the input file depts.txt
  // and create one Department object per line in the file.
  // Add all objects to the list.
  // Be sure to close the scanner object using a finally block.
  // Handle possible execptions by producing a nice error
  // along with the execption's message to standard error
  // (NOT standard output).
  return list;
}

正如你所看到的，这段代码什么都不做，只返回一个空 ArrayList，所以它表明你有点倒退。您将需要修复程序的这一部分，让它在文本文件首先中阅读，然后修复displayDepartments(...)方法，以便您可以测试readDepartmentsFromFile是否正常工作之前尝试使用depts ArrayList！

实现Scanner将文本文件读取到数组

*更新了TestApp

1 个答案: