提示用户提供就业信息。

Question

我创建了一个简单的程序，在这个程序中，用户会被提示提供有关他们就业的各种细节。在我的Employee.java文件中，我有所有的方法。

Employee.java:

import javax.swing.JOptionPane;

public class Employee {

    private static String name;
    private static String jobTitle;
    private static int age;
    private static int salary;
    private static int taxAmount;
    private static int salaryPostTax;

    public static int getSalary() {
        try {
            String inputSalary = JOptionPane.showInputDialog("Enter your salary:");
            salary = Integer.parseInt(inputSalary);

        } catch (Exception ex) {
            JOptionPane.showMessageDialog(null, "ERROR! That's NOT a numeric value.");
        }
        return salary;
    }

    public static String getName() {
        name = JOptionPane.showInputDialog("Enter your name:");
        return name;
    }

    public static String getJobTitle() {
        jobTitle = JOptionPane.showInputDialog("Enter your Job Title:");
        return jobTitle;
    }

    public static int getAge() {
        try {
            String inputAge = JOptionPane.showInputDialog("Enter your age:");
            age = Integer.parseInt(inputAge);

        } catch (Exception ex) {
            JOptionPane.showMessageDialog(null, "ERROR! That's NOT a numeric value.");
        }
        return age;
    }

    public static int calcTaxAmount () {

        if (salary < 10_000)
            taxAmount = 0;

        if ((salary >= 10_000) && (salary < 30_000))
            taxAmount = 28;

        if ((salary >= 30_000) && (salary < 80_000))
            taxAmount = 38;

        if (salary >= 80_000)
            taxAmount = 48;

        return taxAmount;
    }

    public static int calcSalary () {
        salaryPostTax = salary - taxAmount;

        return salaryPostTax;
    }

    public static void showPayment() {
        if (inputValid() == true) {

            JOptionPane.showMessageDialog(null, "Pay to the order of " + name + " (" + jobTitle +
                    ") the sum of £"+ salaryPostTax);
        } else {
            JOptionPane.showMessageDialog(null, "ERROR! Please fill in ALL the required fields correclty.");
        }
    }

    public static boolean inputValid() {
        if (
                (name != null) &&
                (jobTitle != null) &&
                (!(salary <= 0)) &&
                (!(salaryPostTax <= 0)) &&
                (!(age <= 0))) {
            return true;

        } else {
            return false;
        }
    }
}

我有一个使用类的文件(UseIt.java)。不过，我的问题是:这是否是一个好的编程实践：

1.将所有的方法放在一个方法中，只需调用一个方法，而不是单独调用它们，这就变成了累人的？

。

Employee.java：(示例1)

//Collate ALL Employee details into ONE method
public static void getAllDetails() {
    Employee.getName();
    Employee.getAge();
    Employee.getJobTitle();
    Employee.getSalary();
    Employee.calcTaxAmount();
    Employee.calcSalary();
    Employee.showPayment();
}

UseIt.java：(示例1)

public class UseIt {

    static Employee foo = new Employee();

    public static void main(String[] args) {
        foo.getAllDetails(); //Calling ONE method, rather than all of them.
    }
}

2.将所有方法放入构造函数中，以便方法在创建实例？

时自动运行。

Employee.java (例2)

//Collate ALL Employee details into the constructor
public Employee() {
    Employee.getName();
    Employee.getAge();
    Employee.getJobTitle();
    Employee.getSalary();
    Employee.calcTaxAmount();
    Employee.calcSalary();
    Employee.showPayment();
}

UseIt.java (例2)

public class UseIt {

    public static void main(String[] args) {
        Employee foo = new Employee();
    }
}

Answer 1

所以请原谅任何编译错误。

作为一个新手，有很多东西要学，我首先要了解固体原理，同时也要注意Java程序员犯的十大错误。

您要做的第一件事是避开启动程序的static main(String[] args)方法。您不想使用静态方法。因此，您需要实例化您的系统(MySystem)，以便您处于对象的世界中。

你想把你的责任分开。

总是喜欢不变性。

这里我有一个不可变的Employee对象(一旦实例化就不能更改它)。从我们的DetailsRetriever将从用户获得输入的主要方法，这使用DetailsValidator来确保输入是正确的。如果所有细节都正确，则Factory将创建employee对象。

public class UseIt {

    public static void main(String[] args) {
        MySystem foo = new MySystem(new DetailsRetriever(new DetailsValidator()), new EmployeeFactory())
        foo.start();
    }
}

public class MySystem {

   private final DetailsRetreiver detailsRetriever;
   private final EmployeeFactory employeeFactory;

   public MySystem(DetailsRetreiver detailsRetriever, EmployeeFactory employeeFactory) {
         this.detailsRetriever = detailsRetriever;
         this.employeeFactory = employeeFactory;
   }

   public void start() {
         String name = detailsRetriever.retrieveName();
         String jobTitle = detailsRetriever.retrieveJobTitle();
         ..etc

         Employee employee = employeeFactory.create(name, jobTitle, ..etc);
   }

}

public class Employee {

    private final String name;
    private final String jobTitle;
    private final int age;
    private final int salary;

    public Employee(String name, String jobTitle, int age, int salary) {
        this.name = name;
        this.jobTitle = jobTitle;
        this.age = age;
        this.salary = salary;
    }

   public int calcTaxAmount() {
    int calculatedTax;
    if (salary < 10_000)
        calculatedTax = 0;

    if ((salary >= 10_000) && (salary < 30_000))
        calculatedTax = 28;

    if ((salary >= 30_000) && (salary < 80_000))
        calculatedTax = 38;

    if (salary >= 80_000)
        calculatedTax = 48;

    return taxAmount;
}

   public int calcSalary() {
    int calculatedSalaryPostTax = salary - calcTaxAmount();

    return calculatedSalaryPostTax;
   }

}

public class DetailsRetreiver {

    private final DetailsValidator detailsValidator;

    public DetailsRetreiver(DetailsValidator detailsValidator) {
      this.detailsValidator - detailsValidator;
    }

    public String getName() {
        String name = JOptionPane.showInputDialog("Enter your name:");
        if(detailsValidator.validateName(name)) {
          return name;
        } else {
           return getName(); // or throw an exception
        }
    }

    // etc ...

}

public class DetailsValidator {

     public boolean validateName(String input) {
          // add more validation as you need
          return !"".equals(input);
     }

     // etc
}

public class EmployeeFactory {

      public Employee create(String name, String jobTitle, int age, ... etc) {
           return new Employee(name, jobTitle, age .. etc); 
      }

}