java.net.URL类

package com.mozq.boot.kuayu01.demo;

import java.net.MalformedURLException;
import java.net.URL;

public class URL_01 {
    public static void main(String[] args) {
        try {
            URL url = new URL("");
            /*
            URL url = new URL("");
            java.net.MalformedURLException: no protocol:
                at java.net.URL.<init>(URL.java:593)
                at java.net.URL.<init>(URL.java:490)
                at java.net.URL.<init>(URL.java:439)
             */
            /*
            URL url = new URL(null);
            java.net.MalformedURLException
                at java.net.URL.<init>(URL.java:627)
                at java.net.URL.<init>(URL.java:490)
                at java.net.URL.<init>(URL.java:439)
                at com.mozq.boot.kuayu01.demo.URL_01.main(URL_01.java:10)
            Caused by: java.lang.NullPointerException
                at java.net.URL.<init>(URL.java:532)
                ... 3 more
             */
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }
}