URL下载网络资源

URL

https://www.baidu.com/
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 XXX.X..X..X

协议：//ip地址：端口/项目名/资源

package com.wang.netStudy.lesson04;

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=wsh&password=123");
        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.wang.netStudy.lesson04;

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

public class UrlDown {
    public static void main(String[] args) throws IOException {
        //1.下载地址
        URL url = new URL("http://localhost:8080/helloworld/index.txt");

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

        InputStream is = urlConnection.getInputStream();

        FileOutputStream fos = new FileOutputStream("index.txt");

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

        fos.close();
        is.close();
        urlConnection.disconnect();//断开连接
    }
}