Java中以时钟的效果显示时间

超、凢脫俗 2023-09-26 20:44 84阅读 0赞

可以使用Java语言中的控制台输出函数和定时器来实现在IDEA控制台输出时间的时钟效果。具体步骤如下：

1. 获取当前系统时间

Date currentTime = new Date();  // 获取当前系统时间
    int hour = currentTime.getHours();  // 获取小时
    int minute = currentTime.getMinutes();  // 获取分钟
    int second = currentTime.getSeconds();  // 获取秒钟

2. 输出时钟效果

while(true) {
        currentTime = new Date();
        hour = currentTime.getHours();
        minute = currentTime.getMinutes();
        second = currentTime.getSeconds();
        System.out.print("\r" + hour + ":" + minute + ":" + second);
        Thread.sleep(1000);
    }

上述代码中通过 while 循环不断地更新系统时间，并使用 System.out.print() 函数实现控制台输出。其中 "\\r" 表示光标返回到行首，实现覆盖输出的效果；Thread.sleep() 函数实现了每秒刷新一次的效果。这样就能够在IDEA控制台中输出类似于时钟的效果了。

下面是输出一个图形化时钟的代码

package test;
    
    
    import javax.swing.JFrame;
    import javax.swing.JPanel;
    import javax.swing.Timer;
    import java.awt.Color;
    import java.awt.Font;
    import java.awt.Graphics;
    import java.awt.Graphics2D;
    import java.awt.Point;
    import java.awt.RenderingHints;
    import java.util.Calendar;
    
    public class Clock extends JPanel {
        private static final long serialVersionUID = 1L;
    
        public static void main(String[] args) {
            JFrame frame = new JFrame("Clock");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(400, 400);
            frame.setLocationRelativeTo(null); // 居中显示
            Clock clock = new Clock();
            frame.add(clock);
            frame.setVisible(true);
    
            Timer timer = new Timer(1000, e -> {
                clock.repaint();
            });
            timer.start();
        }
    
        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g;
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    
            int width = getWidth();
            int height = getHeight();
            int size = Math.min(width, height); // 时钟大小
    
            // 画圆，作为表盘
            g2d.setColor(Color.WHITE);
            g2d.fillOval((width - size) / 2, (height - size) / 2, size, size);
            g2d.setColor(Color.BLACK);
            g2d.drawOval((width - size) / 2, (height - size) / 2, size, size);
    
            Point center = new Point(width / 2, height / 2);
            int radius = size / 2 - 10; // 刻度线离表盘边框的距离
    
            // 画刻度线
            for (int i = 0; i < 12; i++) {
                double angle = Math.PI / 6 * i;
                int x1 = (int) (center.x + Math.cos(angle) * radius);
                int y1 = (int) (center.y - Math.sin(angle) * radius);
                int len = i % 3 == 0 ? 20 : 10;
                int x2 = (int) (center.x + Math.cos(angle) * (radius - len));
                int y2 = (int) (center.y - Math.sin(angle) * (radius - len));
                g2d.drawLine(x1, y1, x2, y2);
            }
    
            // 画时针、分针、秒针
            Calendar now = Calendar.getInstance();
            int hour = now.get(Calendar.HOUR);
            int minute = now.get(Calendar.MINUTE);
            int second = now.get(Calendar.SECOND);
    
            double hourAngle = Math.PI / 6 * (hour + minute / 60.0);
            int hourHandLen = radius / 2; // 时针长度
            int hourHandWidth = 5; // 时针宽度
            int xh = (int) (center.x + Math.cos(hourAngle) * hourHandLen);
            int yh = (int) (center.y - Math.sin(hourAngle) * hourHandLen);
            g2d.setColor(Color.BLACK);
            g2d.setStroke(new java.awt.BasicStroke(hourHandWidth));
            g2d.drawLine(center.x, center.y, xh, yh);
    
            double minuteAngle = Math.PI / 30 * minute;
            int minuteHandLen = radius * 3 / 4; // 分针长度
            int minuteHandWidth = 3; // 分针宽度
            int xm = (int) (center.x + Math.cos(minuteAngle) * minuteHandLen);
            int ym = (int) (center.y - Math.sin(minuteAngle) * minuteHandLen);
            g2d.setColor(Color.BLACK);
            g2d.setStroke(new java.awt.BasicStroke(minuteHandWidth));
            g2d.drawLine(center.x, center.y, xm, ym);
    
            double secondAngle = Math.PI / 30 * second;
            int secondHandLen = radius * 4 / 5; // 秒针长度
            int secondHandWidth = 1; // 秒针宽度
            int xs = (int) (center.x + Math.cos(secondAngle) * secondHandLen);
            int ys = (int) (center.y - Math.sin(secondAngle) * secondHandLen);
            g2d.setColor(Color.RED);
            g2d.setStroke(new java.awt.BasicStroke(secondHandWidth));
            g2d.drawLine(center.x, center.y, xs, ys);
    
            // 画中心点
            int pointSize = 10; // 中心点大小
            g2d.fillOval(center.x - pointSize / 2, center.y - pointSize / 2, pointSize, pointSize);
    
            // 显示时间
            Font font = new Font("Arial", Font.PLAIN, 20);
            g2d.setFont(font);
            String timeStr = String.format("%02d:%02d:%02d", hour, minute, second);
            int strWidth = g2d.getFontMetrics().stringWidth(timeStr); // 字符串宽度
            int strHeight = g2d.getFontMetrics().getHeight(); // 字符串高度
            g2d.drawString(timeStr, center.x - strWidth / 2, center.y + strHeight / 2);
        }
    }