SearchEngines.java Servlet that redirects requests to various search engines. Uses the SearchSpec helper class. Accessed by means of SearchEngines.html.

SearchEngines.java  Servlet that redirects requests to various search engines. Uses the SearchSpec  helper class. Accessed by means of SearchEngines.html. 

package cwp;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.net.*;

/** Servlet that takes a search string, number of results per
 *  page, and a search engine name, sending the query to
 *  that search engine. Illustrates manipulating
 *  the response status line. It sends a 302 response
 *  (via sendRedirect) if it gets a known search engine,
 *  and sends a 404 response (via sendError) otherwise.
 *  


 *  Taken from Core Web Programming Java 2 Edition
 *  from Prentice Hall and Sun Microsystems Press,
 *  .
 *  May be freely used or adapted.
 */

public class SearchEngines extends HttpServlet {
  public void doGet(HttpServletRequest request,
                    HttpServletResponse response)
      throws ServletException, IOException {
    String searchString = request.getParameter("searchString");
    if ((searchString == null) ||
        (searchString.length() == 0)) {
      reportProblem(response, "Missing search string.");
      return;
    }
    // The URLEncoder changes spaces to "+" signs and other
    // non-alphanumeric characters to "%XY", where XY is the
    // hex value of the ASCII (or ISO Latin-1) character.
    // Browsers always URL-encode form values, so the
    // getParameter method decodes automatically. But since
    // we're just passing this on to another server, we need to
    // re-encode it.
    searchString = URLEncoder.encode(searchString);
    String numResults = request.getParameter("numResults");
    if ((numResults == null) ||
        (numResults.equals("0")) ||
        (numResults.length() == 0)) {
      numResults = "10";
    }
    String searchEngine =
      request.getParameter("searchEngine");
    if (searchEngine == null) {
      reportProblem(response, "Missing search engine name.");
      return;
    }
    SearchSpec[] commonSpecs = SearchSpec.getCommonSpecs();
    for(int i=0; i" + message + "");
  }

  public void doPost(HttpServletRequest request,
                     HttpServletResponse response)
      throws ServletException, IOException {
    doGet(request, response);
  }
}



SearchSpec.java

package cwp;

/** Small class that encapsulates how to construct a
 *  search string for a particular search engine.
 *  


 *  Taken from Core Web Programming Java 2 Edition
 *  from Prentice Hall and Sun Microsystems Press,
 *  May be freely used or adapted.
 */

public class SearchSpec {
  private String name, baseURL, numResultsSuffix;

  private static SearchSpec[] commonSpecs =
    { new SearchSpec("google",
                     "http://www.google.com/search?q=",
                     "&num="),
      new SearchSpec("infoseek",
                     "http://infoseek.go.com/Titles?qt=",
                     "&nh="),
      new SearchSpec("lycos",
                     "http://lycospro.lycos.com/cgi-bin/" +
                        "pursuit?query=",
                     "&maxhits="),
      new SearchSpec("hotbot",
                     "http://www.hotbot.com/?MT=",
                     "&DC=")
    };

  public SearchSpec(String name,
                    String baseURL,
                    String numResultsSuffix) {
    this.name = name;
    this.baseURL = baseURL;
    this.numResultsSuffix = numResultsSuffix;
  }

  public String makeURL(String searchString,
                        String numResults) {
    return(baseURL + searchString +
           numResultsSuffix + numResults);
  }

  public String getName() {
    return(name);
  }

  public static SearchSpec[] getCommonSpecs() {
    return(commonSpecs);
  }
}