链接：https://www.jianshu.com/p/f4016e2e1158

https://blog.csdn.net/xinyuebaihe/article/details/88249561

文件下载后文件损坏的问题，今天做项目碰到了，就顺便做个笔记吧！

本地文件下载：

public void getWordFile(HttpServletRequest request, HttpServletResponse response) throws IOException {   
     private static final String fileNameString = "XXXX.docx"; //声明要下载的文件名      
     //String fileName = new String(fileNameString.getBytes("ISO8859-1"), "UTF-8");      
     response.setContentType("application/octet-stream");   
     // URLEncoder.encode(fileNameString, "UTF-8") 下载文件名为中文的，文件名需要经过url编码      
     response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileNameString, "UTF-8"));   
     File file;   
     FileInputStream fileIn = null;   
     ServletOutputStream out = null;   
     try {   
        String contextPath = ContextLoader.getCurrentWebApplicationContext().getServletContext().getRealPath("/");   
        String filePathString = contextPath + "database" + File.separator + fileNameString;   
        file = new File(filePathString);   
        fileIn = new FileInputStream(file);   
        out = response.getOutputStream();   
  
        byte[] outputByte = new byte[1024];   
        int readTmp = 0;   
        while ((readTmp = fileIn.read(outputByte)) != -1) {   
           out.write(outputByte, 0, readTmp); //并不是每次都能读到1024个字节，所有用readTmp作为每次读取数据的长度，否则会出现文件损坏的错误     
        }   
     }   
     catch (Exception e) {   
        log.error(e.getMessage());   
     }   
     finally {   
        fileIn.close();   
        out.flush();   
        out.close();   
     }   
  }

网络文件下载

https://blog.csdn.net/xiansu5452/article/details/79485388

    public static boolean downloadFile(String fileUrl, String fileLocal) throws Exception {
        boolean flag = false;
        URL url = new URL(fileUrl);
        HttpURLConnection urlCon = (HttpURLConnection) url.openConnection();
        urlCon.setConnectTimeout(6000);
        urlCon.setReadTimeout(6000);
        int code = urlCon.getResponseCode();
        if (code != HttpURLConnection.HTTP_OK) {
            throw new Exception("文件读取失败");
        }
        //读文件流
        DataInputStream in = new DataInputStream(urlCon.getInputStream());
        DataOutputStream out = new DataOutputStream(new FileOutputStream(fileLocal));
        byte[] buffer = new byte[2048];
        int count = 0;
        while ((count = in.read(buffer)) > 0) {
            out.write(buffer, 0, count);
        }
        try {
            if (out != null) {
                out.close();
            }
            if (in != null) {
                in.close();
            }
 
        } catch (Exception e) {
            e.printStackTrace();
        }
        flag = true;
        return flag;
    }