編碼

 /**
     * 線上圖片Base64編碼
     * @param link 線上圖片請求地址
     * @return
     * @throws IOException
     */
    public static String toBase64(String link) {
        byte[] data = null;
        InputStream inputStream = null;
        try {
            URL url = new URL(link);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(5000);
            inputStream = conn.getInputStream();
            //這裡為分界上面程式碼是拿到網路圖片，下面程式碼是編碼
            data = new byte[inputStream.available()];
            if (inputStream != null){
                inputStream.read(data);
            }
            if (inputStream != null){
                inputStream.close();
            }
        }catch (Exception e) {
                    e.printStackTrace();
                }
                BASE64Encoder encoder = new BASE64Encoder();
                return encoder.encode(data);
    }
 

解碼

/**
* 檔案Base64解碼Java示例程式碼
*
* @param str      需要解碼的字元
* @param filePath 生成檔案的路徑
* @return
*/
public static boolean decodeStrToFile(String str, String filePath) {
     if (str == null)
     return false;
     BASE64Decoder decoder = new BASE64Decoder();
     try {
         byte[] bytes = decoder.decodeBuffer(str);
         for (int i = 0; i < bytes.length; ++i) {
              if (bytes[i] < 0) {
                  bytes[i] += 256;
              }
         }
         OutputStream out = new FileOutputStream(filePath);
         out.write(bytes);
         out.flush();
         out.close();
         return true;
     } catch (Exception e) {
         return false;
     }
}