JAVA - 网络/本地图片互转Base64

简介：实际需求是，接口传输图片等文件时，先转成Base64字符串，再传输，然后接受，再转成图片

一、读取网络图片转Base64

 public static String readNetFile(String imgURL){
            ByteArrayOutputStream data = new ByteArrayOutputStream();
            try {
                // 创建URL
                URL url = new URL(imgURL);
                byte[] by = new byte[1024];
                // 创建链接
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setRequestMethod("GET");
                conn.setConnectTimeout(5000);
                InputStream is = conn.getInputStream();
                // 将内容读取内存中
                int len = -1;
                while ((len = is.read(by)) != -1) {
                    data.write(by, 0, len);
                }
                // 关闭流
                is.close();
            } catch (IOException e) {
                e.prin