📄 counterservlet.java
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/* -*- mode:java; indent-tabs-mode:nil; c-basic-offset:2 -*- * $RCSFile$ $Revision: 1.12 $ $Date: 2006/02/06 21:26:47 $ * Copyright (c) 2002-2004 Autonomy Corp. All Rights Reserved. */import java.io.*;import java.util.*;import javax.servlet.*;import javax.servlet.http.*;/** * Example of a click counting Servlet, for use with * <code>CounterSearchable</code>. * * The <code>CounterSearchable</code> rewrites * the URL of each result to redirect through this Servlet which * logs which hit was selected. * <p> * This Servlet should be installed so that it is accessed * via the URL specified in the <code>setCounterLocation()</code> * method of the <code>CounterSearchable</code>. * <p> * If this Servlet is installed as * <tt>http://search.corp.com/count.html</tt> * Then <code>CounterSearchable</code> would rewrite the search * result URL <tt>http://www.corp.com/<tt> as follows: * <tt>http://search.corp.com/count.html?q=home&n=4&url=http://www.corp.com/</tt> * Indicating that for the query "home", the 4th result was selected. * The Servlet should redirect to the desired page <tt>http://www.corp.com/</tt>. * @serial exclude * */public class CounterServlet extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String query = null; String url = null; int num = -1; String id = "none"; // optional argument Enumeration enumeration = req.getParameterNames(); while (enumeration.hasMoreElements()) { String name = (String)enumeration.nextElement(); String[] values = req.getParameterValues(name); if (name.equals("q")) { query = decode(values[0]); } else if (name.equals("n")) { num = parseInt(decode(values[0]), -1); } else if (name.equals("url")) { url = decode(values[0]); } else if (name.equals("id")) { id = decode(values[0]); } } // Send the redirect before we log this, so the user doesn't // have to wait. if (url != null) { resp.sendRedirect(url); } else { error(req, resp); } if (url == null) { log("error: missing url parameter " + req.getRequestURI() + req.getQueryString()); } else if (query == null) { log("error: missing q parameter " + req.getRequestURI() + req.getQueryString()); } else if (num == -1) { log("error: missing n parameter " + req.getRequestURI() + req.getQueryString()); } else { // Everything OK, log it. log(id + " " +url + " " + num + " " + query); } } private void error(HttpServletRequest req, HttpServletResponse resp) throws IOException { // Buffer output to set Content-length and support 1.1 persistent conn. ByteArrayOutputStream bytes = new ByteArrayOutputStream(4096); PrintWriter out = new PrintWriter(bytes,true); out.println("<html><head>"); out.println("<title>Unable to redirect</title>"); out.println("</head><body>"); out.println("Unable to redirect, no URL provided as parameter."); out.println("<p>"); out.println("Please return to the previous page with your browser's"); out.println("<i>Back</i> button."); out.println("</body></html>"); resp.setStatus(HttpServletResponse.SC_OK); resp.setContentType("text/html"); resp.setContentLength(bytes.size()); bytes.writeTo(resp.getOutputStream()); } private static String decode(String value) throws UnsupportedEncodingException { if (value==null) return value; byte[] bytes = value.getBytes(); return new String(bytes, "UTF-8"); } private static int parseInt(String str, int def) { try { return Integer.parseInt( str ); } catch (Exception e) { return def; } }}⌨️ 快捷键说明
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