尝试使用ImageIO加载图像时出现java错误。阅读

Question

在搜索类似问题后，我想问以下问题：

我试图从Google静态地图加载一张图片，但是我得到了这个错误：Exception in thread "main" java.lang.IllegalArgumentException: input == null! at javax.imageio.ImageIO.read(Unknown Source) at MapPicturePanel.main(MapPicturePanel.java:18)

以下是该类的完整代码：

 import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.*;

public class MapPicturePanel {
    private JScrollPane getContent(BufferedImage image) {
        ImageIcon icon = new ImageIcon(image);
        JLabel label = new JLabel(icon);
        label.setHorizontalAlignment(JLabel.CENTER);
        return new JScrollPane(label);
    }

    public static void main(String[] args) throws IOException {
        String path = "http://maps.googleapis.com/maps/api/staticmap?center=37.426616,-122.176380&zoom=14&size=800x600&scale=2&format=jpg&maptype=hybrid&sensor=false";
        URL url = MapPicturePanel.class.getResource(path);
        BufferedImage image = ImageIO.read(url);
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setContentPane(new MapPicturePanel().getContent(image));
        f.setSize(800,800);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}

Answer 1

您正在尝试在类路径中查找资源（这就是Class.getResource所做的）。但看起来您希望从外部url加载图像

就这么做吧

BufferedImage image  - ImageIO.read(new URL(path));