Provisional headers are shown

问题：

文件上传没有返回值，浏览器console显示Provisional headers are shown

服务端处理数据流方式：

InputStreamReader insr = new InputStreamReader(request.getInputStream(),"utf-8"); // 读取服务器的响应内容并显示 String result = ""; int respInt = insr.read(); while(respInt != -1){    result += (char)respInt;    respInt = insr.read(); }

数据流字节少则如上方法可以正常，但是如图片等文件则此方法会出现异常

解决：

服务端处理数据流方式异常，更换服务端数据流处理方式，如：

public static String  ReadAsChars2(HttpServletRequest request) {     InputStream is = null;     StringBuilder sb = new StringBuilder();     try {         is = request.getInputStream();         byte[] b = new byte[4096];         for (int n; (n = is.read(b)) != -1; ) {             sb.append(new String(b, 0, n));         }     } catch (IOException e) {         e.printStackTrace();     } finally {         if (null != is) {             try {                 is.close();             } catch (IOException e) {                 e.printStackTrace();             }         }     }      return sb.toString(); }

来源：51CTO

作者：碧扶摇

链接：https://blog.csdn.net/liuzhen917/article/details/101219025