com.eryansky.common.web.utils.WebUtils.java Source code

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

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/**
 *  Copyright (c) 2012-2014 http://www.eryansky.com
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 */
package com.eryansky.common.web.utils;

import org.apache.commons.lang3.StringUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Map;
import java.util.StringTokenizer;
import java.util.zip.GZIPOutputStream;

/**
 * HttpServlet.
 * 
 * @author &Eryan eryanwcp@gmail.com
 */
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, ?.
     * <p/>
     * , 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?.
     * <p/>
     * 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 + "\"");
    }

    /**
     * ???Request Parameters.
     * <p/>
     * Parameter???.
     */
    public static Map<String, Object> getParametersStartingWith(HttpServletRequest request, String prefix) {
        return org.springframework.web.util.WebUtils.getParametersStartingWith(request, prefix);
    }

    /**
     * ?Ajax.
     * 
     * @param request
     * @return
     */
    public static boolean isAjaxRequest(HttpServletRequest request) {
        String header = request.getHeader("X-Requested-With");
        if (header != null && "XMLHttpRequest".equals(header)) {
            return true;
        } else {
            return false;
        }
    }
}