[java] Accessing post variables using Java Servlets

What is the Java equivalent of PHP's $_POST? After searching the web for an hour, I'm still nowhere closer.

This question is related to java http servlets

The answer is


The previous answers are correct but remember to use the name attribute in the input fields (html form) or you won't get anything. Example:

<input type="text" id="username" /> <!-- won't work --> <input type="text" name="username" /> <!-- will work --> <input type="text" name="username" id="username" /> <!-- will work too -->

All this code is HTML valid, but using getParameter(java.lang.String) you will need the name attribute been set in all parameters you want to receive.


For getting all post parameters there is Map which contains request param name as key and param value as key.

Map params = servReq.getParameterMap();

And to get parameters with known name normal

String userId=servReq.getParameter("user_id");

POST variables should be accessible via the request object: HttpRequest.getParameterMap(). The exception is if the form is sending multipart MIME data (the FORM has enctype="multipart/form-data"). In that case, you need to parse the byte stream with a MIME parser. You can write your own or use an existing one like the Apache Commons File Upload API.


Here's a simple example. I didn't get fancy with the html or the servlet, but you should get the idea.

I hope this helps you out.

<html>
<body>
<form method="post" action="/myServlet">
<input type="text" name="username" />
<input type="password" name="password" />
<input type="submit" />
</form>
</body>
</html>

Now for the Servlet

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class MyServlet extends HttpServlet {
  public void doPost(HttpServletRequest request,
                    HttpServletResponse response)
      throws ServletException, IOException {

    String userName = request.getParameter("username");
    String password = request.getParameter("password");
    ....
    ....
  }
}

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