package wangluobiancheng.lesson04;

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

public class UrlDown {
    public static void main(String[] args) throws Exception {
        //1.下载地址
        URL url = new URL("http://localhost:8080/Alan/Securityfile.txt");
        //2.连接到这个资源 HTTP
        HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();

        InputStream inputStream = urlConnection.getInputStream();

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


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

打开就是这样的