Bitter servlets - Bitter Java - page 61

HttpServletResponse res)
throws ServletException, IOException
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
out.println("Hello World");
out.close();
}
}

D Print writer prints HTML responses
E Printing response for the end user

B This servlet inherits from HTTPServlet , which is the standard communication
between the client and server for this class of application.
C This program is triggered by an HTTP GET request. The other common HTTP
command is POST . Many times, both GET s and POST s are sent to a common
method. These examples consolidate them in a method called performTask .

Server

Web app server

Servlet

F

HTML

E

D

Web server

C g

Hardware

Client

B

Browser

System software

Program artifact

Figure 3.4 B The user makes a request for a servlet. C The browser does an HTTP POST .
D The web server passes the request through to the application server, possibly installed as a
web server plug-in. E The application server invokes the servlet. F The servlet executes and
prints out an HTML page that G is returned to the user.