Using Java servlet to obtain HTML form parameters to send API request

Question

I have an HTML form and want to use Java on the backend. When the form is submitted, I am trying to send a request to an API on the same server. The API request I'm trying to send using a Java SDK requires me to obtain the parameters entered on the HTML form. How can I do this within doPost() in the servlet? Is it possible to use HttpHandler within my servlet doPost() to accomplish this with the POSTed parameters?

Answer 1

Here's a generic form

<form name="loginForm" method="post" action="loginServlet">
Username: <input type="text" name="username"/> <br/>
Password: <input type="password" name="password"/> <br/>
<input type="submit" value="Login" />
</form>

Here, loginServletis your servlet URL.

Your servlet class should extend HttpServlet, and your doPost() method should look like this. Remember to specify your servlet URL inside @webServlet. Alternatively, you can declare and map your servlet inside your web.xml file.

@WebServlet("/loginServlet")
protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    // code to process the form...
}

In the body, you can grab the parameters like so

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

Now you have obtained the form parameters.

Credit to CodeJava http://www.codejava.net/java-ee/servlet/handling-html-form-data-with-java-servlet