URL 是 统一资源定位符,用来定位互联网上的某一个资源,比如 www.baidu.com
DNS 是域名解析,把域名解析成IP地址
格式:
协议://IP地址:端口/项目名/资源
URL 类中的方法:
package com.network.url; import java.net.MalformedURLException; import java.net.URL; public class URLDemo01 { public static void main(String[] args) throws MalformedURLException { URL url = new URL("http://localhost:8080/helloworld/index.jsp?username=zhangsan"); System.out.println(url.getProtocol()); //协议 System.out.println(url.getHost()); //主机ip System.out.println(url.getPort()); //端口 System.out.println(url.getPath()); //文件 System.out.println(url.getFile()); //全路径 System.out.println(url.getQuery()); //参数 } }
package com.network.url; import java.io.FileOutputStream; import java.io.InputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; public class URLDemo02 { public static void main(String[] args) throws Exception { //1.下载地址 URL url = new URL("https://m801.music.126.net/20220730170101/972d74fc0cfac98baa9584ab1d7cdb7d/jdyyaac/obj/w5rDlsOJwrLDjj7CmsOj/14096427565/7854/7b14/6110/6a83aac06435d939143701eebe126ed9.m4a"); //2.连接到这个资源 HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(); //3.下载 InputStream is = urlConnection.getInputStream(); FileOutputStream fos = new FileOutputStream("f:\\test\\gu.m4a"); byte[] buffer = new byte[1024]; int count; while ((count = is.read(buffer)) != -1){ fos.write(buffer); } //关闭 fos.close(); is.close(); urlConnection.disconnect(); } }