getchart.java

OLAP 的客户端代码

/*
 * ====================================================================
 * This software is subject to the terms of the Common Public License
 * Agreement, available at the following URL:
 *   http://www.opensource.org/licenses/cpl.html .
 * Copyright (C) 2003-2004 TONBELLER AG.
 * All Rights Reserved.
 * You must accept the terms of that agreement to use this software.
 * ====================================================================
 */
package com.tonbeller.jpivot.chart;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 *
 * @author  arosselet
 * @version
 */
public class GetChart extends HttpServlet {
    String basePath;
    /** Initializes the servlet.
     */
    final static String fileNotFound="/WEB-INF/jpivot/img_not_found.gif";
    
    public void init(ServletConfig config) throws ServletException {        
        super.init(config);             
    }
    /** Destroys the servlet.
     */
    public void destroy() {
        
    }
    
    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {

        HttpSession session = request.getSession();
        String filename = request.getParameter("filename");
        System.out.println("GetChart called: filename="+filename);
        if (filename == null) {
            throw new ServletException("Parameter 'filename' must be supplied");
        }

        //  Replace ".." with ""
        //  This is to prevent access to the rest of the file system
        filename = searchReplace(filename, "..", "");

        //  Check the file exists
        File file = new File(System.getProperty("java.io.tmpdir"), filename);
        if (!file.exists()) {
            throw new ServletException("File '" + file.getAbsolutePath() + "' does not exist");
        }
         //  Serve it up
        sendTempFile(file, response);
       
        return;

    }
    public static void sendTempFile(File file, HttpServletResponse response)
            throws IOException, FileNotFoundException {

        String mimeType = null;
        String filename = file.getName();
        if (filename.length() > 5) {
            if (filename.substring(filename.length() - 5, filename.length()).equals(".jpeg") || 
                filename.substring(filename.length() - 5, filename.length()).equals(".jpg")) {
                mimeType = "image/jpeg";
            }
            else if (filename.substring(filename.length() - 4, filename.length()).equals(".png")) {
                mimeType = "image/png";
            }
            else if (filename.substring(filename.length() - 4, filename.length()).equals(".gif")) {
                mimeType = "image/gif";
            }
        }
        sendTempFile(file, response, mimeType);
    }

    /**
     * Binary streams the specified file to the HTTP response in 1KB chunks
     *
     * @param file The file to be streamed.
     * @param response The HTTP response object.
     * @param mimeType The mime type of the file, null allowed.
     *
     * @throws IOException  if there is an I/O problem.
     * @throws FileNotFoundException  if the file is not found.
     */
    public static void sendTempFile(File file, HttpServletResponse response,
                                    String mimeType)
            throws IOException, FileNotFoundException {

        if (file.exists()) {
            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));

            //  Set HTTP headers
            if (mimeType != null) {
                response.setHeader("Content-Type", mimeType);
            }
            response.setHeader("Content-Length", String.valueOf(file.length()));
            SimpleDateFormat sdf = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss z");
            response.setHeader("Last-Modified", sdf.format(new Date(file.lastModified())));

            BufferedOutputStream bos = new BufferedOutputStream(response.getOutputStream());
            byte[] input = new byte[1024];
            boolean eof = false;
            while (!eof) {
                int length = bis.read(input);
                if (length == -1) {
                    eof = true;
                } else {
                    bos.write(input, 0, length);
                }
            }
            bos.flush();
            bis.close();
            bos.close();
        }
        else {
            throw new FileNotFoundException(file.getAbsolutePath());
        }
        return;
    }

      /**
     * Perform a search/replace operation on a String
     * There are String methods to do this since (JDK 1.4)
     *
     * @param inputString  the String to have the search/replace operation.
     * @param searchString  the search String.
     * @param replaceString  the replace String.
     *
     * @return the String with the replacements made.
     */
    public static String searchReplace(String inputString,
                                       String searchString,
                                       String replaceString) {

        int i = inputString.indexOf(searchString);
        if (i == -1) {
            return inputString;
        }

        String r = "";
        r += inputString.substring(0, i) + replaceString;
        if (i + searchString.length() < inputString.length()) {
            r += searchReplace(inputString.substring(i + searchString.length()),
                               searchString,
                               replaceString);
        }

        return r;
    }
   
    /** Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    
}