Обучение Java. Сервлеты


Handling GET requests

Handling GET requests involves overriding the doGet method. The following example shows the BookDetailServlet doing this. The methods discussed in the section are shown in bold.

public class BookDetailServlet extends HttpServlet {

public void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { ... // set content-type header before accessing the Writer response.setContentType("text/html");

PrintWriter out = response.getWriter();

// then write the response out.println("<html>" + "<head><title>Book Description</title></head>" + ...);

//Get the identifier of the book to display String bookId = request.getParameter("bookId");

if (bookId != null) { // and the information about the book and print it ... } out.println("</body></html>"); out.close();

} ... }

The servlet extends the HttpServlet class and overrides the doGet method.

Within the doGet method, the getParameter

method gets the servlet's expected argument.

To respond to the client, the example doGet method uses a Writer from the HttpServletResponse object to return text data to the client. Before accessing the writer, the example sets the content-type header. At the end of the doGet method, after the response has been sent, the Writer is closed.

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