URL下载网络资源-2022-12-20

URL 统一资源定位符,定位互联网的某一个资源

DNS 域名解析  WWW.BAIDU.COM  解析成 XXX.X.X.XXX  本质就是把一个域名解析成一个IP

https: 协议   //   IP地址：端口   /  项目名  /   具体资源

www.baidu.com/  

Tomcat 要打开

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

public class UrlDown {
    public static void main(String[] args) throws Exception {

        //1.下载地址
        URL url = new URL("http://localhost:8080/lr/security.text");

        //2.连接这个资源
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        InputStream inputStream = connection.getInputStream();
        
        //3.下载这个资源
        FileOutputStream fos = new FileOutputStream("security.text");

        byte[] buffer2 = new byte[1024];
        int len;
        while ((len = inputStream.read(buffer2))!=-1) {
            fos.write(buffer2,0,len);
        }

        //4.关闭资源
        fos.close();
        inputStream.close();
        connection.disconnect(); 


    }
}