Hackforge Academy

Explanation

Request parameters are values sent by the client as part of the URL query string or HTML form data.

Code:

GET /users?id=101

id = 101

Explanation

Use getParameter() to retrieve a single request parameter.

Code:

String name = request.getParameter("name");
System.out.println(name);

Explanation

Use getParameterValues() when multiple values can be submitted with the same parameter name.

Code:

String[] skills =
    request.getParameterValues("skill");

for (String skill : skills) {
    System.out.println(skill);
}

Explanation

HTML form fields are submitted to the servlet using their name attributes.

Code:

<form action="register" method="post">
    <input type="text" name="username">
    <input type="email" name="email">
    <button type="submit">Register</button>
</form>

Explanation

The servlet can read the submitted form data and process it.

Code:

protected void doPost(HttpServletRequest request,
                      HttpServletResponse response)
                      throws IOException {

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

    response.getWriter()
            .println(username + " - " + email);
}