java - HTTPServlet Request.getInputStream() 总是接收空行

Question

客户端:

    public List<String> post(List<String> toWrite){
        String result = "";
        List<String> allResults = new ArrayList<String>();

        try {
            openConnection();
            connection.setDoOutput(true);
            connection.setRequestMethod("POST");
            initializeOutputStream();
            for(int i = 0; i < toWrite.size(); i++){
                out.write(toWrite.get(i));
                out.newLine();
            }
            System.out.println(connection.getResponseCode());
            System.out.println(connection.getResponseMessage());
            initializeInputStream();
            while((result = in.readLine()) != null){
                allResults.add(result);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            closeConnection();
        }

        return allResults;
    }

One of the attempts at the host:

    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        // TODO Auto-generated method stub
        List<String> incoming = new ArrayList<String>();

//      BufferedReader in = req.getReader();
//
//      String tmp = in.readLine();

        resp.setContentType("text/plain");
        PrintWriter out = resp.getWriter();

        StringBuilder stringBuilder = new StringBuilder();  
        BufferedReader bufferedReader = null;  
        try {  
          InputStream inputStream = req.getInputStream();  
          if (inputStream != null) {  
           bufferedReader = new BufferedReader(new InputStreamReader(  
        inputStream));  
           char[] charBuffer = new char[128];  
           int bytesRead = -1;  
           //while ((bytesRead = bufferedReader.read(charBuffer)) > 0) {
           while(bytesRead != -1){
            stringBuilder.append(charBuffer, 0, bytesRead);  
           }  
          } else {  
           stringBuilder.append("");  
          }  
        } catch (IOException ex) {  
          throw ex;  
        } finally {  
          if (bufferedReader != null) {  
           try {  
            bufferedReader.close();  
           } catch (IOException ex) {  
            throw ex;  
           }  
          }  
        }  
        String body = stringBuilder.toString();  
        System.out.println(body);

        out.println(body);

//      BufferedReader in = new BufferedReader(new InputStreamReader(req.getInputStream()));        
//      
//      String tmp = "";
//      
//      //while(!(in.ready())){}
//      
//      while((tmp = in.readLine()) != null){
//          System.out.println(tmp);
//      }
//
//
//      out.println(tmp);

        out.println("end");

    }

请注意注释掉的行 - 这是我尝试从客户那里获取信息的众多其他尝试之一。

servlett 中的 System.out.printlns 和 out.printlns 都返回空行。程序结束时的“结束”返回没有问题。这不是在客户端读回多行的问题 - 如果我放置多个 out.println，那么我可以很好地读取它们。输入流的 system.out.println() 也返回空白。状态码是200，看来没有连接错误。

有人吗？

Answer 1

看起来你的 while 循环在这里没有做任何事情，因为在你的情况下，bytesRead 总是 -1 因此它永远不会进入循环，而且，你不'根本不要使用您的 bufferedReader 从输入流中读取:-

    int bytesRead = -1;
    while (bytesRead != -1) {
        stringBuilder.append(charBuffer, 0, bytesRead);
    }

试试这个:-

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    resp.setContentType("text/plain");
    PrintWriter out = resp.getWriter();

    StringBuilder stringBuilder = new StringBuilder(1000);
    Scanner scanner = new Scanner(req.getInputStream());
    while (scanner.hasNextLine()) {
        stringBuilder.append(scanner.nextLine());
    }

    String body = stringBuilder.toString();

    System.out.println(body);
    out.println(body);

}