Question

我目前不是java的新手，但我第一次收到此错误是我的代码示例！解释为什么即使我实现了mouseListener方法，我也似乎无法使我的代码能够与IntelliJ一起工作

package com.company;

import org.w3c.dom.events.MouseEvent;

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

public class AppMenu extends JMenuBar implements MouseListener {

    //  Constants
    private static String menufile = "File";
    private static String editmenu = "Edit";
    private static String aboutmenu = "About";

    //  Constructor
    public AppMenu() {
        super();

        this.add(newMenu(menufile));
        this.add(newMenu(editmenu));
        this.add(newMenu(aboutmenu));
    }

    //  This function create new menu for the App Menu
    private JMenu newMenu(String _name){
        JMenu newMenu = new JMenu(_name);
        //newMenu.addMouseListener(this);
        return newMenu;
    }

    public void mouseExited(MouseEvent e) {}

    public void mousePressed(MouseEvent e) {}

    public void mouseReleased(MouseEvent e) {}

    public void mouseEntered(MouseEvent e) {}

    public void mouseClicked(MouseEvent e) {}
}

Answer 1

var query = function(sql) {
    return new Promise(function(resolve, reject) {
        var returnValue = "";
        db.query(sql, function(error, rows) {
            if (error) {
                returnValue = "";
            } else {
                returnValue = rows[0]['url'];
                console.log("in function result: " + returnValue);
            }
            resolve(returnValue)
        });
    });
};

var getSlaveURL = async function() {
    var sqlQuery = "SELECT url FROM `slave` WHERE `id`='2' LIMIT 1";
    let result = await query(sqlQuery)
    console.log("out function result: " + result);
};

getSlaveURL();

是错误的导入，你想要

import org.w3c.dom.events.MouseEvent;

快速查看How to Write a Mouse Listener和JavaDocs for MouseListener上的示例会突出显示特定问题

实现鼠标侦听器java时出错

1 个答案: