Question

我将此代码添加到Netbeans，我得到的文件test1不包含main()函数。

我添加了main()功能，但仍然收到此错误：

import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JToolBar;
import javax.swing.KeyStroke;

import net.miginfocom.swing.MigLayout;

public class test1 extends JFrame {

    // Window Vars //
    String title;
    int width;
    int height;

    // Mid Level componets //
    JMenuBar menuBar;
    JMenu file;
    JToolBar toolBar;
    JPanel map;
    JPanel sideBar;

    // Low Level componets //
    JMenuItem exit;

    JButton select;

    public test1(String title, int width, int height) {
        this.title = title;
        this.width = width;
        this.height = height;
        this.makeInterface();
    }

    public void makeInterface() {
        // Setup JFrame
        this.setTitle(title);
        this.setSize(width, height);
        this.setLocationRelativeTo(null);
        this.setMinimumSize(new Dimension(700, 500));
        this.setVisible(true);

        this.setLayout(new MigLayout(
                "debug, fillx, gap unrel rel",  // Layout
                "[grow, fill][fill]",         // Column
                "[fill][fill]"));       // Row
        this.makeMenu();
        this.addToolBars();
        this.makePanels();
        this.setupActionListeners();
    }

    public void makeMenu() {
        this.menuBar = new JMenuBar();
        this.file = new JMenu("File");
        this.file.setMnemonic(KeyEvent.VK_F);
        this.menuBar.add(file);

        this.exit = new JMenuItem("Exit", KeyEvent.VK_E);
        this.exit.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_E, ActionEvent.ALT_MASK));
        this.file.add(exit);

        this.setJMenuBar(this.menuBar);
    }

    public void addToolBars() {
        this.toolBar = new JToolBar("Draggable");
        this.addToolBarButtons();
        this.add(toolBar, "span, height 20:35:50, wrap");
    }

    public void addToolBarButtons() {
        this.select = new JButton("Select");
        this.toolBar.add(select);
    }

    public void makePanels() {
        this.map = new JPanel();
        this.sideBar = new JPanel();

        this.add(map, "width 400:600:, flowy, growy");
        this.add(sideBar, "width 250:300:350, flowy, growy");
    }

    public void setupActionListeners() {
        this.exit.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
    }
    public static void main(){
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new test1("r",400,400).setVisible(true);
            }
        });
    }
}

有人可以找出问题所在吗？

Answer 1

main的正确签名是

public static void main(String[] args)

Answer 2

你需要作为参数（String [] args）

Answer 3

main函数声明中缺少必需的参数.main的正确语法是：

public static void main(String args[])

Answer 4

如果您使用的是像Eclipse这样的IDE。我建议你输入ma并自动填充它，这样你就不会犯任何错误。

即使main（）存在，也没有main（）

4 个答案: