图片路径问题:Swing--ImageIcon(url)

源代码：

import javax.swing.*;
import java.awt.*;
import java.net.URL;

public class ImageDemo1 extends JFrame {

    public ImageDemo1(){
        JLabel label = new JLabel("小事情");
        //获取图片的地址
        URL url = ImageDemo1.class.getResource("ye.jpg");

        ImageIcon imageIcon = new ImageIcon(url);
        label.setIcon(imageIcon);
        label.setHorizontalAlignment(SwingConstants.CENTER);

        Container container = getContentPane();
        container.add(label);

        setVisible(true);
        setBounds(100,100,500,400);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }
    public static void main(String[] args) {
        new ImageDemo1();
    }
}

报错：

Exception in thread "main" java.lang.NullPointerException
	at javax.swing.ImageIcon.<init>(ImageIcon.java:217)
	at com.ggl.lesson04.ImageDemo1.<init>(ImageDemo1.java:16)
	at com.ggl.lesson04.ImageDemo1.main(ImageDemo1.java:29)

Process finished with exit code 1

报错原因：

//获取图片的地址
        URL url = ImageDemo1.class.getResource("ye.jpg");
        ImageIcon imageIcon = new ImageIcon(url);

//路径为null，空指针异常

//可以进行如下修改：
    ImageIcon imageIcon = new ImageIcon("src/com/ggl/lesson04/ye.jpg");

修改后的代码：

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


public class ImageDemo1 extends JFrame {

    public ImageDemo1(){
        JLabel label = new JLabel("小事情");
        //获取图片的地址
       ImageIcon imageIcon = new ImageIcon("src/com/ggl/lesson04/ye.jpg");

        label.setIcon(imageIcon);
        label.setHorizontalAlignment(SwingConstants.CENTER);

        Container container = getContentPane();
        container.add(label);

        setVisible(true);
        setBounds(100,100,700,600);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }
    public static void main(String[] args) {
        new ImageDemo1();
    }
}

运行效果：

图片路径问题:Swing--ImageIcon(url)

原文：https://www.cnblogs.com/javastudys/p/java_03.html