文件输入和输出流

@Test
    public void TestChiPan() throws IOException {
       // File file=new File("G:\\timg.jpg");
        //File file=new File("C:\\Users\\win10\\Desktop\\新建文件夹\\答辩PPT.pptx");
        File file=new File("wenjian/1.jpg");
        InputStream inputStream=new FileInputStream(file);
        byte[] pic=new byte[inputStream.available()];
        inputStream.read(pic);
        inputStream.close();

        File file2 = new File("wenjian/3.jpg");
        FileOutputStream outputStream = new FileOutputStream(file2);
        outputStream.write(pic);
        outputStream.close();

    }


服务器返回文件
  @RequestMapping("/downLoadFile")
    public  void DownLoadFile(HttpServletRequest request, HttpServletResponse response) throws IOException {
        String fileName=request.getParameter("fileName");
        response.setContentType("text/html;charset=utf-8");
        response.setCharacterEncoding("utf-8");
        System.out.println(fileName);
        //FileInputStream in = new FileInputStream("G:\\"+fileName);
        FileInputStream in = new FileInputStream("/"+fileName);
        response.setHeader("content-disposition",
                "attachment;filename=" + URLEncoder.encode("fileName", "utf-8"));
        OutputStream out = response.getOutputStream();
        // 创建缓冲区
        byte buffer[] = new byte[1024];
        int len = 0;
        // 循环将输入流中的内容读取到缓冲区中
        while ((len = in.read(buffer)) > 0) {
            // 输出缓冲区内容到浏览器，实现文件下载
            out.write(buffer, 0, len);
        }
        // 关闭文件流
        in.close();
        // 关闭输出流
        out.close();
    }


android 从服务器下载文件
@Test
    public void TestDownLoadFile() throws IOException {
        URL url = new URL("http://localhost/downLoadFile/downLoadFile?fileName=timg.jpg");
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setReadTimeout(5000);
        con.setConnectTimeout(5000);
        con.setRequestProperty("Charset", "UTF-8");
        con.setRequestMethod("GET");
        if (con.getResponseCode() == 200) {
            InputStream is = con.getInputStream();//获取输入流
            FileOutputStream fileOutputStream = null;//文件输出流
            if (is != null) {
                fileOutputStream = new FileOutputStream("G:\\TestMysql\\tig.jpg");//指定文件保存路径，代码看下一步
                byte[] buf = new byte[1024];
                int ch;
                while ((ch = is.read(buf)) != -1) {
                    fileOutputStream.write(buf, 0, ch);//将获取到的流写入文件中
                    System.out.println("写文件");
                }
            }
            if (fileOutputStream != null) {
                fileOutputStream.flush();
                fileOutputStream.close();
            }
        }
    }