java网络下载图片到本地

String path = "https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1546100952419&di=4b9466f689800898b761d411c0eed2d2&imgtype=0&src=http%3A%2F%2Fb.hiphotos.baidu.com%2Fzhidao%2Fpic%2Fitem%2F14ce36d3d539b600d3924a1feb50352ac65cb73e.jpg";
        try{
            URL url = null;
            int imageNumber = 0;

            try {
                url = new URL(path);
                DataInputStream dataInputStream = new DataInputStream(url.openStream());

                String imageName =  "E:/test.jpg";

                FileOutputStream fileOutputStream = new FileOutputStream(new File(imageName));
                ByteArrayOutputStream output = new ByteArrayOutputStream();

                byte[] buffer = new byte[1024];
                int length;

                while ((length = dataInputStream.read(buffer)) > 0) {
                    output.write(buffer, 0, length);
                }
                byte[] context=output.toByteArray();
                fileOutputStream.write(output.toByteArray());
                dataInputStream.close();
                fileOutputStream.close();
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

从网络下载图片到本地（尝试成功）

 

//文件下载相关代码
    @GetMapping("/downloadImage")
    public String downloadImage( HttpServletResponse response) {
        String fileUrl = "https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1546100952419&di=4b9466f689800898b761d411c0eed2d2&imgtype=0&src=http%3A%2F%2Fb.hiphotos.baidu.com%2Fzhidao%2Fpic%2Fitem%2F14ce36d3d539b600d3924a1feb50352ac65cb73e.jpg";

        if (fileUrl != null) {
            //下载时文件名称
            String fileName = fileUrl.substring(fileUrl.lastIndexOf("/" + 1));
            DataInputStream fis = null;
            BufferedInputStream bis = null;
            try {
                URL url = new URL(fileUrl);
                fis = new DataInputStream(url.openStream());

                response.setContentType("application/force-download");// 设置强制下载不打开
                response.addHeader("Content-Disposition",
                        "attachment;fileName=" + fileName);// 设置文件名
                byte[] buffer = new byte[1024];
                bis = new BufferedInputStream(fis);
                OutputStream os = response.getOutputStream();
                int i = bis.read(buffer);
                while (i != -1) {
                    os.write(buffer, 0, i);
                    i = bis.read(buffer);
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (bis != null) {
                    try {
                        bis.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (fis != null) {
                    try {
                        fis.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
        return null;
    }

尝试过已经成功，公司框架是前后端分离的，不明白为啥GetMapping就可以进行下载，但是用PostMapping就不行了，浏览器没反应