java - 将 javax.swing 转换为命令输入

Question

如何将javax.swing.*转换为正常的命令行提示符？我尝试在 https://compilr.com/ 上测试代码但由于它有 javax.swing.* 它不会提示对话框。

import javax.swing.*;

public class Program
{
  public static void main ( String[] args)
  {
    int numOfGrades = 0, gradeCount = 0, sum = 0;
    char grade;
    String openMsg, getNumOfGrades, getGrades, outMsg1, gradeOut;

    openMsg = "Welcome.\n\n" +
    "Grading Scale: A = 4, B = 3, C = 2, D = 1, F = 0\n\n" +
    "Please tell me how many grades to enter today:";
    getNumOfGrades = JOptionPane.showInputDialog ( openMsg );
    numOfGrades = Integer.parseInt ( getNumOfGrades );



    while ( gradeCount != numOfGrades )
    {
      getGrades =  JOptionPane.showInputDialog("Please enter grade number: "+ (gradeCount+1) + "\n" +
      "Grading Scale: A = 4, B = 3, C = 2, D = 1, F = 0\n\n");
      grade = getGrades.charAt ( 0 );
      JOptionPane.showMessageDialog ( null, grade );

      //int sum = 0;

      switch(grade)
      {
      case 'a': case 'A':
        grade = 4;
        break;
      case 'b': case 'B':
        grade = 3;
        break;
      case 'c': case 'C':
        grade = 2;
        break;
      case 'd': case 'D':
        grade = 1;
        break;
      case 'f': case 'F':
        grade = 0;
        break;
      default:
        String errOut = "Sorry, Invalid entry. Exiting Program!";
        JOptionPane.showMessageDialog ( null, errOut );
        break;
      }

      sum += grade;

      gradeCount++;
    }

    double gpa = sum / gradeCount;

    outMsg1 = "You entered " + numOfGrades + " grades\n" +
    "Your GPA is: " + gpa + "\n" +
    "These were the grades you entered: "; //+ grade;  

    JOptionPane.showMessageDialog ( null, outMsg1 );

    System.exit ( 0 );

  }
}

Answer 1

这完全取决于您想要做什么。如果您只想要一个可运行的程序，那么最简单的方法是使用命令行参数来传递您的输入，而不是提示输入。

要运行的类名称后面的每个命令行参数都作为 main 方法接收的 args 字符串数组传入。所以你可以简单地从这个数组中读取它们。

如果您想提示输入，那么您需要使用System.out.println 写出消息。可以使用 System.in 从“标准输入”读取输入。由于这是一个输入流，因此通常包装在 BufferedReader 和输入流读取器中。例如

BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
System.out.println("Type some data");
String theData = reader.readLine()