java.io.IOException: Stream closed 的問題

public static String getBodyString(ServletRequest request) {
        StringBuilder sb = new StringBuilder();
        InputStream inputStream = null;
        BufferedReader reader = null;
        InputStreamReader isr = null;
        try {
            inputStream = request.getInputStream();
            isr = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
            //reader = new BufferedReader(new InputStreamReader(inputStream, Charset.forName("UTF-8")));
            reader = new BufferedReader(isr);
            String line = "";
            while ((line = reader.readLine()) != null) {
                sb.append(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (isr != null) {
                try {
                    isr.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return sb.toString();
    }

當普通請求進來沒有處理字節流，所以流不存在關閉。

當文件資源請求進來，會經過請求封裝的流處理過程，流關閉后，在過濾器中被重復使用。報錯！

所以要對文件資源的請求做單獨放行的處理。