com.klwork.common.utils.WebUtils.java Source code

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Here is the source code for com.klwork.common.utils.WebUtils.java

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/**
 * Copyright (c) 2005-2009 springside.org.cn
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * 
 * $Id: WebUtils.java 763 2009-12-27 18:36:21Z calvinxiu $
 */
package com.klwork.common.utils;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import java.util.StringTokenizer;
import java.util.zip.GZIPOutputStream;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringUtils;

/**
 * HttpServlet.
 * 
 * @author calvin
 */
public class WebUtils {

    public static final long ONE_YEAR_SECONDS = 60 * 60 * 24 * 365;

    /**
     *  Header.
     */
    public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) {
        //Http 1.0 header
        response.setDateHeader("Expires", System.currentTimeMillis() + expiresSeconds * 1000);
        //Http 1.1 header
        response.setHeader("Cache-Control", "max-age=" + expiresSeconds);
    }

    /**
     * Header.
     */
    public static void setNoCacheHeader(HttpServletResponse response) {
        //Http 1.0 header
        response.setDateHeader("Expires", 0);
        //Http 1.1 header
        response.setHeader("Cache-Control", "no-cache");
    }

    /**
     * LastModified Header.
     */
    public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) {
        response.setDateHeader("Last-Modified", lastModifiedDate);
    }

    /**
     * Etag Header.
     */
    public static void setEtag(HttpServletResponse response, String etag) {
        response.setHeader("ETag", etag);
    }

    /**
     * ??If-Modified-Since Header, ?.
     * 
     * , checkIfModifyfalse ,304 not modify status.
     * 
     * @param lastModified ?.
     */
    public static boolean checkIfModifiedSince(HttpServletRequest request, HttpServletResponse response,
            long lastModified) {
        long ifModifiedSince = request.getDateHeader("If-Modified-Since");
        if ((ifModifiedSince != -1) && (lastModified < ifModifiedSince + 1000)) {
            response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
            return false;
        }
        return true;
    }

    /**
     * ?? If-None-Match Header, Etag?.
     * 
     * Etag, checkIfNoneMatchfalse, 304 not modify status.
     * 
     * @param etag ETag.
     */
    public static boolean checkIfNoneMatchEtag(HttpServletRequest request, HttpServletResponse response,
            String etag) {
        String headerValue = request.getHeader("If-None-Match");
        if (headerValue != null) {
            boolean conditionSatisfied = false;
            if (!"*".equals(headerValue)) {
                StringTokenizer commaTokenizer = new StringTokenizer(headerValue, ",");

                while (!conditionSatisfied && commaTokenizer.hasMoreTokens()) {
                    String currentToken = commaTokenizer.nextToken();
                    if (currentToken.trim().equals(etag)) {
                        conditionSatisfied = true;
                    }
                }
            } else {
                conditionSatisfied = true;
            }

            if (conditionSatisfied) {
                response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
                response.setHeader("ETag", etag);
                return false;
            }
        }
        return true;
    }

    /**
     * ???gzip?.
     */
    public static boolean checkAccetptGzip(HttpServletRequest request) {
        //Http1.1 header
        String acceptEncoding = request.getHeader("Accept-Encoding");

        if (StringUtils.contains(acceptEncoding, "gzip")) {
            return true;
        } else {
            return false;
        }
    }

    /**
     * Gzip HeaderGZIPOutputStream.
     */
    public static OutputStream buildGzipOutputStream(HttpServletResponse response) throws IOException {
        response.setHeader("Content-Encoding", "gzip");
        response.setHeader("Vary", "Accept-Encoding");
        return new GZIPOutputStream(response.getOutputStream());
    }

    /**
     * ??Header.
     * 
     * @param fileName ???.
     */
    public static void setDownloadableHeader(HttpServletResponse response, String fileName) {
        response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");
    }

    /**
     * ???
     * @param request
     * @param response
     */
    public static void VerificationCode(HttpServletRequest request, HttpServletResponse response) throws Exception {
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        // 
        int width = 60, height = 20;
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);

        // ?
        Graphics g = image.getGraphics();

        // ??
        Random random = new Random();

        // 
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);

        // 
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));

        // 
        // g.setColor(new Color());
        // g.drawRect(0,0,width-1,height-1);

        // ?155?????
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }

        String base = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQUSTUVWXYZ0123456789";
        // ????(4?)
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            int start = random.nextInt(base.length());
            String rand = base.substring(start, start + 1);
            sRand = sRand.concat(rand);
            // ??
            g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 13 * i + 6, 16);
        }

        // ??SESSION
        request.getSession().setAttribute("entrymrand", sRand);

        // 
        g.dispose();
        OutputStream out = response.getOutputStream();
        // ?
        ImageIO.write(image, "JPEG", out);

        out.flush();
        out.close();
    }

    /**
     * ?
     * @param fc
     * @param bc
     * @return
     */
    public static Color getRandColor(int fc, int bc) {
        Random random = new Random();
        if (fc > 255)
            fc = 255;
        if (bc > 255)
            bc = 255;
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

}