java - Java格式错误的url异常，用于简单的url

Question

令人沮丧的格式错误的url异常。作为测试，我添加了“ URL url = new URL(” http://www.google.com“); ”只是为了查看一个非常简单的URL是否会引发错误，并且确实如此。我不知道是什么原因造成的。

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

public class Train {

public static void main(String[] args) {
    URL url = new URL("http://www.google.com");
    ImageIcon icon = new ImageIcon(new URL("https://upload.wikimedia.org/wikipedia/commons/d/d4/Wikipedesketch1.png"));**
    Integer miles = Integer.parseInt(JOptionPane.showInputDialog("Enter the miles"));
    Double gallons = Double.parseDouble(JOptionPane.showInputDialog("Enter the gallons"));  
    Double mpg = miles / gallons;
    JOptionPane.showMessageDialog(null, "Miles per gallon is " + mpg, "Gass Mileage", JOptionPane.PLAIN_MESSAGE, icon); 
}

}

线程“主”中的异常java.lang.Error: Unresolved 编译问题:
未处理的异常类型MalformedURLException
未处理的异常类型MalformedURLException

at Train.main(Train.java:13)

Answer 1

您有编译错误，没有try/catch for抛出异常
新的ImageIcon()

尝试这个:

import javax.swing.*;
import java.net.*;
public class Train {
    public static void main(String[] args) {
        try {
        URL url = new URL("http://www.google.com");
        ImageIcon icon = new ImageIcon(new URL("https://upload.wikimedia.org/wikipedia/commons/d/d4/Wikipedesketch1.png"));
        Integer miles = Integer.parseInt(JOptionPane.showInputDialog("Enter the miles"));
        Double gallons = Double.parseDouble(JOptionPane.showInputDialog("Enter the gallons"));  
        Double mpg = miles / gallons;
        JOptionPane.showMessageDialog(null, "Miles per gallon is " + mpg, "Gass Mileage", JOptionPane.PLAIN_MESSAGE, icon);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}