java中什么方法可以在微信服务器上面把图片下载到本地服务器并保存（知道微信服务器上面图片的链接）

java中什么方法可以在微信服务器上面把图片下载到本地服务器并保存（知道微信服务器上面图片的链接）

根据图片链接，转成byte存入数据库，数据库格式为Blob

    public static byte[] image2Base64(String imageUrl){
        URL url = null;
        InputStream is = null;
        ByteArrayOutputStream outputStream = null;
        HttpURLConnection connection = null;
        try {
            url = new URL(imageUrl);
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setConnectTimeout(5000);
            connection.connect();
            is = connection.getInputStream();
            outputStream = new ByteArrayOutputStream();
            byte[] buffer = new byte[1024];
            int len = 0;
            while ((len = is.read(buffer)) != -1){
                outputStream.write(buffer, 0,len);
            }
            return outputStream.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        }
        finally{
            if(is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(connection != null) {
                connection.disconnect();
            }
        }
        return null;
    }

    /**
     * 
     * @param imageUrl 图片地址
     * @param path 文件下载目录
     */
    public static void downloadImage(String imageUrl, String path) {
        URL url = null;
        InputStream is = null;
        OutputStream outputStream = null;
        HttpURLConnection connection = null;
        try {
            url = new URL(imageUrl);
            connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.setConnectTimeout(5000);
            connection.connect();
            is = connection.getInputStream();
            String suffix = imageUrl.substring(imageUrl.lastIndexOf("."));

            File directory = new File(path);
            if (!directory.exists()){
                directory.mkdirs();
            }
            if (!directory.isDirectory()){
                throw new RuntimeException("所传的不是目录地址");
            }
            File file = new File(directory,UUID.randomUUID().toString() + suffix);
            outputStream = new FileOutputStream(file);
            byte[] buffer = new byte[1024];
            int len = 0;
            while ((len = is.read(buffer)) != -1) {
                outputStream.write(buffer, 0, len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (connection != null) {
                connection.disconnect();
            }
        }
    }