java下载网络文件、图片等资源_各种文件以及图片的下载 java-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_38410147/article/details/121211367

该博客展示了如何使用Java的HttpURLConnection类从网络读取文件并将其下载到本地。代码实现了设置超时、模拟浏览器请求头以及将输入流转换为字节数组的功能，确保了文件的稳定获取和存储。

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import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
public class FileUtil {
/*读取网络文件*/
    public static InputStream getFileInputStream(String path) {
        URL url = null;
        try {
            url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            //设置超时间为3秒
            conn.setConnectTimeout(5*1000);
            //防止屏蔽程序抓取而返回403错误
            conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
            //得到输入流
            return conn.getInputStream();
        } catch (Exception e) {
            log.error("读取网络文件异常:"+path);
        }
        return null;
    }

    public void  downLoadFromUrl(String urlStr,String fileName,String savePath) throws IOException{
        InputStream fileInputStream = getFileInputStream(urlStr);
//        if (isOk) {
//           log.info("获取输入流："+fileInputStream.toString());
//            //文件保存位置
//            String s =savePath+fileName;
//            if (huaweiyunOss.uploadFile(s, HuaweiyunOss.FileType.FILES, fileInputStream)) {
//                log.info("download success!!");
//            }else{
//                log.info("download false!!");
//            }
//        }else{
            //获取自己数组
        byte[] getData = readInputStream(fileInputStream);
        File saveDir = new File(savePath);
        if(!saveDir.exists()){
            saveDir.mkdir();
        }
        File file = new File(saveDir+File.separator+fileName);
        FileOutputStream output = new FileOutputStream(file);
        output.write(getData);
        if(output!=null){
            output.close();
        }
        log.info("download success!!");
//        }
        if(fileInputStream!=null){
            fileInputStream.close();
        }
    }

    public byte[] readInputStream(InputStream inputStream) throws IOException {
        byte[] buffer = new byte[10240];
        int len = 0;
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        while((len = inputStream.read(buffer)) != -1) {
            bos.write(buffer, 0, len);
        }
        bos.close();
        return bos.toByteArray();
    }
}