在try-catch塊之后有代碼時，try-Catch不會重新運行

Question

我正在嘗試在do-while循環中運行多個try-catch塊來幫助捕獲諸如整數和雙輸入的InputMissMatch之類的錯誤，但是，我仍然需要能夠在相同的do-while循環中從輸入字符串控制台界面。

是否有可能在捕獲異常后使try-catch塊重新運行，而不是移至下一行代碼，如果可以，怎么辦？

這是我的代碼：

import java.util.HashMap;
import java.util.InputMismatchException;
import java.util.Map;
import java.util.Scanner;


public class EmployeeBenefits {

    Map <Integer, CaptureDetails> map = new HashMap<> ();

    int number;
    String name;
    String surname;
    double grossSalary;

    int employeeNumber = 1;
    int numberOfEmployees = 0;

    public void captureDetails() {

        boolean codeIsRunning = true;

        Scanner input = new Scanner (System.in);

        do {

            inputNumberOfEmployees ();

            if (numberOfEmployees != 0) {

                for (int enterDetails = 0; enterDetails < numberOfEmployees; enterDetails++) {

                    inputEmployeeNumber ();
                    inputEmployeeNames ();
                    inputGrossSalary ();

                    map.put(employeeNumber, new CaptureDetails (number, name, surname, grossSalary));
                    employeeNumber++;
                }
            }

            codeIsRunning = false;

        } while (codeIsRunning); // end of do-while loop

    } //  end of captureDetails () method

    public void inputNumberOfEmployees () {

        Scanner input = new Scanner (System.in);

        try {

            System.out.print ("Enter the number of employees to input: ");
            numberOfEmployees = input.nextInt();

        }
        catch (InputMismatchException e) {

            System.out.println ("\nYou must enter an integer value. Please try agin\n");
            input.nextLine();
        }

    } // end of inputNumberOfEmployees()

    public void inputEmployeeNumber () {

        Scanner input = new Scanner (System.in);

        try {

            System.out.print ("Enter Number: ");
            number = input.nextInt();

        } catch (InputMismatchException e) {

            System.out.println("\nYou must enter an integer value. Please try agin\n");
            input.nextLine ();

        }

    } // end of inputEmployeeNumber()

    public void inputGrossSalary () {

        Scanner input = new Scanner (System.in);

        try {
            System.out.print ("Enter Gross Salary: ");
            grossSalary = input.nextDouble();
        }
        catch (InputMismatchException e) {
            System.out.println ("\nEnter employees salary. Please try agin\n");
            input.nextLine ();
        }

    } // inputGrossSalary ()

    public void inputEmployeeNames () {

        Scanner input = new Scanner (System.in);

        System.out.print ("Enter Name: ");
        name = input.nextLine();

        System.out.print ("Enter Surname: ");
        surname = input.nextLine();

    } // end of inputEmployeeNames

    public static void main(String[] args) {

        EmployeeBenefits eb = new EmployeeBenefits ();

        boolean programIsRunning = true;

        Scanner input = new Scanner (System.in);

        while (programIsRunning) {

            System.out.println ("1. Enter Employee details");
            System.out.println ("2. Set New Salary");
            System.out.println ("3. Print Employee Details");
            System.out.println ("4. Exit");

            switch (input.nextInt()) {

                case 1:
                    eb.captureDetails ();
                    break;
                case 2:
                    break;
                case 3:
                    break;
                case 4:
                    programIsRunning = false;
                    break;

                default :
                    System.out.println ("Enter a value between from 1 to 4\n");

            } // end of switch-case (input.nextInt())

        } // end of while (programIsRunning) loop  

    } // end of main method

} // end of EmployeeBenefits class


class CaptureDetails {

    int number;
    String name, surname;
    double grossSalary;

    public CaptureDetails (int number, String name, String surname, double grossSalary) {

        this.number = number;
        this.name = name;
        this.surname = surname;
        this.grossSalary = grossSalary;

    }

} // end of CaptureDetails class

Answer 1

您可以從catch語句中調出方法，也可以添加一個while循環來檢查有效輸入。

public void inputNumberOfEmployees () {

    Scanner input = new Scanner (System.in);

    try {

        System.out.print ("Enter the number of employees to input: ");
        numberOfEmployees = input.nextInt();

    }
    catch (InputMismatchException e) {

        System.out.println ("\nYou must enter an integer value. Please try agin\n");
        inputNumberOfEmployees(); // This is the Change
    }

} // end of inputNumberOfEmployees()

Answer 2

這樣的事情可能會起作用：

public void inputEmployeeNumber () {

    Scanner input = new Scanner (System.in);

    boolean isValid = false;
    while (!isValid)
    {
        try {

            System.out.print ("Enter Number: ");
            number = input.nextInt();
            isValid = true;

        } catch (InputMismatchException e) {

            System.out.println("\nYou must enter an integer value. Please try agin\n");
            input.nextLine ();

        }
    }

} // end of inputEmployeeNumber()

Answer 3

您當然可以在循環中提示輸入。 問題是...您沒有使用循環：

public void inputNumberOfEmployees () {
    Scanner input = new Scanner (System.in);
    try {
        System.out.print ("Enter the number of employees to input: ");
        numberOfEmployees = input.nextInt();
    }
    catch (InputMismatchException e) {
        System.out.println ("\nYou must enter an integer value. Please try agin\n");
        input.nextLine();
    }
}

如果要循環執行此邏輯，則將其包裝在循環中。 在這種情況下，終止條件將是輸入是否成功。 因此，您可以使用一個簡單的布爾標志來跟蹤它。 也許是這樣的：

public void inputNumberOfEmployees () {
    Scanner input = new Scanner (System.in);

    boolean isInvalid = true;
    while (isInvalid) {

        try {
            System.out.print ("Enter the number of employees to input: ");
            numberOfEmployees = input.nextInt();

            isInvalid = false;
        }
        catch (InputMismatchException e) {
            System.out.println ("\nYou must enter an integer value.\n");
        }

    }
}

Answer 4

嘗試在catch塊內嘗試執行continue label語句以嘗試block 。 它將反復嘗試獲取輸入，直到沒有異常被捕獲為止