querygenerator.java

servlet与jsp核心编程 书籍源码 部分

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.
 *  <P>
 *  Taken from Core Servlets and JavaServer Pages
 *  from Prentice Hall and Sun Microsystems Press,
 *  http://www.coreservlets.com/.
 *  &copy; 2000 Marty Hall; may be freely used or adapted.
 */

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<queries.length; i++) {
      queries[i] = randomQuery();
      if (useNumbering) {
        queries[i] = "" + (i+1) + ": " + queries[i];
      }
    }
    return(queries);
  }

  // The real, honest-to-goodness queries people have sent :-)
  
  private String randomQuery() {
    String[] locations = { "Where ", "How " };
    String[] actions =
      { "can I look for ", "can I find ", "can I get " };
    String[] sources =
      { "information ", "resources ", "data ", "references " };
    String[] prepositions = { "on ", "about ", "concerning " };
    String[] subjects =
      { "the book Core Servlets and JavaServer Pages",
        "the text Core Servlets and JavaServer Pages",
        "Core Servlets and JavaServer Pages",
        "Core Servlets and JSP",
        "the book Core Web Programming (Java 2 Edition)",
        "Core Web Programming (Java 2 Edition)",
        "servlet programming", "JavaServer Pages", "JSP",
        "Java alternatives to CGI", "server-side Java" };
    String[] endings = { "?", "?", "?", "?!", "?!!!?" };
    String[][] sentenceTemplates =
      { locations, actions, sources,
        prepositions, subjects, endings };
    String query = "";
    for(int i=0; i<sentenceTemplates.length; i++) {
      query = query + randomEntry(sentenceTemplates[i]);
    }
    return(query);
  }

  private String randomEntry(String[] strings) {
    int index = (int)(Math.random()*strings.length);
    return(strings[index]);
  }
}