Using Request Data

Example 4-1 shows a servlet that uses many of the HttpServletRequest methods.

Example 4-1. Using HttpServletRequest methods
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Iterator;
import java.util.Map;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
  
public class HelloYou extends HttpServlet {
    public void doGet(HttpServletRequest request, 
        HttpServletResponse response) 
        throws ServletException, IOException {
  
        String name = request.getParameter("name");
        if (name == null) {
            name = "you";
        }
        response.setContentType("text/html");
        PrintWriter out = response.getWriter( );
        out.println("<html><body>");
        out.println("<h1>Hello " + name + "</h1>");
  
        out.println("I see that:<ul>");
        String userAgent = request.getHeader("User-Agent");
        out.println("<li>your browser is: " + userAgent);
        String requestURI = request.getRequestURI( );
        out.println("<li>the URI for this page is: " +
            requestURI);
        String contextPath = request.getContextPath( );
        out.println("<li>the context path for this app is" +
            contextPath);
        String servletPath = request.getServletPath( );
        out.println("<li>this servlet is mapped to: " + 
            servletPath);
        String pathInfo = request.getPathInfo( );
        out.println("<li>the remaining path is: " + pathInfo);
        Map parameters = request.getParameterMap( ); out.println("<li>you sent the following params:<ul>"); Iterator i = parameters.keySet( ).iterator( ); while (i.hasNext( ...

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