网络编程之 URL 下载网络资源

例如：https://www.baidu.com

URL【统一资源定位符】：定位资源的，定位互联网上的某一个资源。

DNS 域名解析：www.baidu.com【某一域名】指向 39.156.69.79【某一网站空间IP】

URL 组成：协议://ip地址:端口/项目名/资源

 

 

URL：统一资源定位符

 

package lesson04;

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

/**
 * URL：统一资源定位符
 */
public class URLDemo1 {

    public static void main(String[] args) throws MalformedURLException {
        URL url = new URL("http://localhost:8080/helloworld/index.jsp?username=kuangshen&password=123");
        //协议名
        System.out.println(url.getProtocol());
        //主机名-主机ip
        System.out.println(url.getHost());
        //端口
        System.out.println(url.getPort());
        //地址-文件路径
        System.out.println(url.getPath());
        //文件-全路径
        System.out.println(url.getFile());
        //查询部分-参数
        System.out.println(url.getQuery());
    }

}

URL下载资源

 

package lesson04;

import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

/**
 * URL下载资源
 */
public class URLDown {

    public static void main(String[] args) throws Exception {
        //1、下载地址
        URL url = new URL("https://m10.music.126.net/20201121104035/2c5eb73ce4421a090b62647f6c486e2c/yyaac/obj/wonDkMOGw6XDiTHCmMOi/3625445007/7d37/4109/d0ef/d56e8176f5789a4e6f8b2173ce500bf6.m4a");

        //2、连接到这个资源 HTTP
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();

        InputStream inputStream = urlConnection.getInputStream();

        FileOutputStream fos = new FileOutputStream("f6.m4a");

        byte[] buffer = new byte[1024];
        int len;
        while ((len = inputStream.read(buffer)) != -1){
            fos.write(buffer, 0, len); //写出这个数据
        }

        //关闭
        fos.close();
        inputStream.close();

        //断开连接
        urlConnection.disconnect();
    }

}

效果一览