December 2003
Intermediate to advanced
764 pages
24h 58m
English
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Generating a Response
Besides
the
request object, the container passes an object that implements the
HttpServletResponse interface as an argument to
the doGet( ) and doPost( )
methods. This interface defines methods for getting a writer or
stream for the response body. It also defines methods for setting the
response status code and headers. Example 19-3
contains the code for a servlet that uses some of the methods.
Example 19-3. Using HttpServletResponse methods
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloMIME extends HttpServlet {
private static final int TEXT_TYPE = 0;
private static final int IMAGE_TYPE = 1;
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
String greeting = "Hello World!";
int majorType = TEXT_TYPE;
String type = request.getParameter("type");
if ("plain".equals(type)) {
response.setContentType("text/plain");
}
else if ("html".equals(type)) {
response.setContentType("text/html");
greeting = "<html><body><h1>" + greeting +
"</h1></body></html>";
}
else if ("image".equals(type)) {
response.setContentType("image/gif");
majorType = IMAGE_TYPE;
}
else {
response.sendError(HttpServletResponse.SC_BAD_REQUEST,
"Please specify a valid response type");
return;
}
if (majorType == TEXT_TYPE) {
PrintWriter out = response.getWriter( );
out.println(greeting);
}
else {
OutputStream os = response.getOutputStream( ); ServletContext application = getServletContext( ); InputStream ...Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.