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17.4 A Query Viewer That Uses Object Serialization and HTTP Tunneling

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Listing 17.6 QueryGenerator.java 

package coreservlets;

import java.io.*; 

import javax.servlet.*;

import javax.servlet.http.*;

/** Servlet that generates an array of strings and

 *  sends them via an ObjectOutputStream to applet

 *  or other Java client.

 */

public class QueryGenerator extends HttpServlet {

  public void doGet(HttpServletRequest request,

                    HttpServletResponse response)

      throws ServletException, IOException {

    boolean useNumbering = true;

    String useNumberingFlag =

      request.getParameter("useNumbering");

    if ((useNumberingFlag == null) ||

        useNumberingFlag.equals("false")) {

      useNumbering = false;

    }

    String contentType =

      "application/x java serialized object";

    response.setContentType(contentType);

    ObjectOutputStream out =

      new ObjectOutputStream(response.getOutputStream());

    String[] queries = getQueries(useNumbering);

    // If you send a nonstandard data structure, be

    // sure it is defined with "implements Serializable".

    out.writeObject(queries);

    out.flush();

  }

  public void doPost(HttpServletRequest request,

                     HttpServletResponse response)

      throws ServletException, IOException {

    doGet(request, response);

  }

  private String[] getQueries(boolean useNumbering) {

    String[] queries = new String[50];

    for(int i=0; i