1.加载servlet容器

不能使用main方法直接调用

  public static boolean httpDownload(String httpUrl, String saveFile) {        // 1.下载网络文件        int byteRead;        URL url;        try {            url = new URL(httpUrl);        } catch (MalformedURLException e1) {            e1.printStackTrace();            return false;        }         try {            //2.获取链接            URLConnection conn = url.openConnection();            //3.输入流            InputStream inStream = conn.getInputStream();            //3.写入文件            FileOutputStream fs = new FileOutputStream(saveFile);             byte[] buffer = new byte[1024];            while ((byteRead = inStream.read(buffer)) != -1) {                fs.write(buffer, 0, byteRead);            }            inStream.close();            fs.close();            return true;        } catch (FilenotFoundException e) {            e.printStackTrace();            return false;        } catch (IOException e) {            e.printStackTrace();            return false;        }    }      @Test    public void httpDownload() {        httpDownload("http://video.zhihuishu.com/zhs/ablecommons/demo/201806/dddee1c446314b84a26c74a8def3c3c7.mp4","E:\\test/22.mp4");    }

2.添加common-io依赖

import org.apache.commons.io.FileUtils; import java.io.File;import java.net.URL; public class TestDownloadFile {     public static void main(String[] args) throws Exception{        String urlStr = "https://img2018.cnblogs.com/i-beta/1278703/201911/1278703-20191128121650595-812419505.png";        URL url = new URL(urlStr);        String tempFileName = "E://a.png";        File temp = new File(tempFileName);        FileUtils.copyURLToFile(url, temp);    }}