Java 我的GUI程序有什么问题

我已经看了这个代码好几个小时了，但不知道出了什么问题。它是从教科书上抄下来的。当我点击run时，只有一个空盒子出现。它应该显示汽车，一个在左上角，一个在右下角。

方法

paintComponent

拼写错误，因此它不会覆盖超类方法。因此，只调用绘制空白框的默认方法

有一种方法可以通过

@Override

注释避免这种常见的错误。通过将此注释添加到重写超类方法或实现接口方法的所有方法中，如果您键入错误的方法名称，而不是创建难以调试的错误，编译器将因错误而停止：

import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.Point2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;

public class Car {

private int xLeft;
private int yTop;

public Car(int x, int y){
    xLeft =x;
    yTop=y;
}

public void draw(Graphics2D g2){
    Rectangle body = new Rectangle(xLeft, yTop+10, 60, 10);
    Ellipse2D.Double frontTire= new Ellipse2D.Double(xLeft+10, yTop+20, 10,     10);
     Ellipse2D.Double rearTire= new     Ellipse2D.Double(xLeft+40,yTop+20,10,10);
    Point2D.Double r1 = new Point2D.Double(xLeft+10,yTop+10);
    Point2D.Double r2 = new Point2D.Double(xLeft+20,yTop);
    Point2D.Double r3 = new Point2D.Double(xLeft+40,yTop);
    Point2D.Double r4 = new Point2D.Double(xLeft+50,yTop+10);
    Line2D.Double frontWindshield = new  Line2D.Double(r1,r2);
    Line2D.Double roofTop = new  Line2D.Double(r2,r3);
    Line2D.Double rearWindshield = new  Line2D.Double(r3,r4);

    g2.draw(body);
    g2.draw(frontTire);
    g2.draw(rearTire);
    g2.draw(frontWindshield);
    g2.draw(roofTop);
    g2.draw(rearWindshield);
 }
}

import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.JComponent;

public class CarComponent extends  JComponent {
public void paintCompnent(Graphics g){
    Graphics2D g2 = (Graphics2D) g;
    Car car1 = new Car(0,0);
     int x = getWidth()-60;
     int y = getHeight()-30;

     Car car2 = new Car(x,y);
     car1.draw(g2);
     car2.draw(g2);
 }
}

import javax.swing.JFrame;
public class CarViewer {

     public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.setSize(400,500);
    frame.setTitle("Two Cars");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    CarComponent component = new CarComponent();
    frame.add(component);

    frame.setVisible(true);
    }

 }

---

将

paintComponent

重命名为

paintComponent

谢谢！你是个天才！

@Override
public void paintComponent(Graphics g){
    // code here
}