java - 错误: Could not find or load main class

Question

我是 Java 编程新手，并将其作为学校项目进行。这是我写的代码

public static void main(String args[])
import javax.swing.*;
import java.awt.event.*;
public class SleepCounter extends JFrame {
  private JPanel panel;
  private JLabel messageLabel;
  private JTextField sleepTextField;
  private JTextField sleepAnswerField;
  private final int WINDOW_WIDTH = 310;
  private final int WINDOW_HEIGHT = 100;
  public SleepCounter() {
    setTitle("Sleep Counter");
    setSize(WINDOW_WIDTH, WINDOW_HEIGHT);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    buildPanel();
    add(panel);
    setVisible(true);
  }
  private void buildPanel() {
    dailyLabel = new JLabel("Enter Sleep " + "in hours");
    hourTextField = new JTextField(10);
    CalcButton = new JButton("Calculate");
    CalcButton.addActionListener(new CalcButtonListener());
    panel = new JPanel();
    panel.add(dailyLabel);
    panel.add(sleepTextField);
    panel.add(CalcButton);
    panel.add(sleepAnswerField);
  }
  private class CalcButtonListener implements ActionListener {
    public void actionPerformer(ActionEvent e) {
      String input;
      int total;
      input = sleepTextField.getText();
      for (int i = 0; i < 7; i++); {
        input += total;
      }
      JOptionPane.showMessageDialog(null, "The total amount of sleep for " + (i + 1) + "days is" + total);
      if (int i > 7) {
        double avg = (total / 7);
        JOptionPane.showMessageDialog(null, "The avg amount of sleep for 7 days is" + avg);
      }
    }
  }
}

运行时我收到一条错误消息:

Error: Could not find or laod main class Graduation Project.

我已经搜索了这个网站并尽可能多地检查了答案。我将不胜感激您提供的任何帮助。

Answer 1

您已将 main 方法放在类之外

 public class  YourClass
 {
  public static void main(String args[])
   {  
   }
  }

将其放入其中并记住在这些导入之前不能放置任何东西

import javax.swing.*;
import java.awt.event.*;