HTTPServlet Request.getInputStream()始终接收空白行 [英] HTTPServlet Request.getInputStream() always receiving blank line
问题描述
客户:
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,这是我尝试从客户端获取内容的许多其他尝试之一.
Please note the commented out lines- thats one of the many other attempts I've tried to get stuff from the client.
System.out.printlns和out.printlns都返回一个空行.程序末尾的"end"没有问题地返回.在客户端读回多行不是问题-如果我将多行out.println放进去,那么我就读得很好.输入流的system.out.println()也返回空白.状态代码为200,因此似乎没有连接错误.
System.out.printlns and out.printlns from the servlett all return a blank line. The "end" at the end of the program returns without problem. It is not a problem of reading multiple lines back on the client side- if I put multiple out.println's, then I read them fine. The system.out.println() for the inputstream also returns blank. The status code is 200, so there seems to be no connection errors.
有人吗?
推荐答案
您的while循环似乎在这里什么也不做,因为在您的情况下,bytesRead
始终为-1,因此它将永远不会进入循环而且,您根本不会使用bufferedReader
来读取输入流:-
It seems like your while loop doesn't do anything here, because in your case, bytesRead
is always -1 thus it will never get into the loop at all, and further, you don't use your bufferedReader
at all to read from the input stream:-
int bytesRead = -1;
while (bytesRead != -1) {
stringBuilder.append(charBuffer, 0, bytesRead);
}
尝试一下:-
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);
}
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