com.androidwhy.modules.web.Servlets.java Source code

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Here is the source code for com.androidwhy.modules.web.Servlets.java

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/**
 * Copyright (c) 2009-2012 androidwhy.com
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 */
package com.androidwhy.modules.web;

import com.androidwhy.modules.utils.Encodes;
import com.google.common.net.HttpHeaders;
import org.apache.commons.lang3.Validate;

import javax.servlet.ServletRequest;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.UnsupportedEncodingException;
import java.util.*;
import java.util.Map.Entry;

/**
 * HttpServlet.
 * 
 * @author Gordon
 */
public class Servlets {

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

    /**
     *  Header.
     */
    public static void setExpiresHeader(HttpServletResponse response, long expiresSeconds) {
        // Http 1.0 header, set a fix expires date.
        response.setDateHeader(HttpHeaders.EXPIRES, System.currentTimeMillis() + expiresSeconds * 1000);
        // Http 1.1 header, set a time after now.
        response.setHeader(HttpHeaders.CACHE_CONTROL, "private, max-age=" + expiresSeconds);
    }

    /**
     * ?Header.
     */
    public static void setNoCacheHeader(HttpServletResponse response) {
        // Http 1.0 header
        response.setDateHeader(HttpHeaders.EXPIRES, 1L);
        response.addHeader(HttpHeaders.PRAGMA, "no-cache");
        // Http 1.1 header
        response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache, no-store, max-age=0");
    }

    /**
     * LastModified Header.
     */
    public static void setLastModifiedHeader(HttpServletResponse response, long lastModifiedDate) {
        response.setDateHeader(HttpHeaders.LAST_MODIFIED, lastModifiedDate);
    }

    /**
     * Etag Header.
     */
    public static void setEtag(HttpServletResponse response, String etag) {
        response.setHeader(HttpHeaders.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(HttpHeaders.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(HttpHeaders.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(HttpHeaders.ETAG, etag);
                return false;
            }
        }
        return true;
    }

    /**
     * ??Header.
     * 
     * @param fileName ???.
     */
    public static void setFileDownloadHeader(HttpServletResponse response, String fileName) {
        try {
            // ???
            String encodedfileName = new String(fileName.getBytes(), "ISO8859-1");
            response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + encodedfileName + "\"");
        } catch (UnsupportedEncodingException e) {
        }
    }

    /**
     * ???Request Parameters, copy from spring WebUtils.
     * 
     * Parameter???.
     */
    public static Map<String, Object> getParametersStartingWith(ServletRequest request, String prefix) {
        Validate.notNull(request, "Request must not be null");
        Enumeration paramNames = request.getParameterNames();
        Map<String, Object> params = new TreeMap<String, Object>();
        if (prefix == null) {
            prefix = "";
        }
        while (paramNames != null && paramNames.hasMoreElements()) {
            String paramName = (String) paramNames.nextElement();
            if ("".equals(prefix) || paramName.startsWith(prefix)) {
                String unprefixed = paramName.substring(prefix.length());
                unprefixed = unprefixed.replace("__", ".");
                String[] values = request.getParameterValues(paramName);
                if (values == null || values.length == 0) {
                    // Do nothing, no values found at all.
                } else if (values.length > 1) {
                    params.put(unprefixed, values);
                } else {
                    params.put(unprefixed, values[0]);
                }
            }
        }
        return params;
    }

    /**
     * ?Parameters?Query StringParameter, paramter nameprefix.
     * 
     * @see #getParametersStartingWith
     */
    public static String encodeParameterStringWithPrefix(Map<String, Object> params, String prefix) {
        if (params == null || params.size() == 0) {
            return "";
        }

        if (prefix == null) {
            prefix = "";
        }

        StringBuilder queryStringBuilder = new StringBuilder();
        Iterator<Entry<String, Object>> it = params.entrySet().iterator();
        while (it.hasNext()) {
            Entry<String, Object> entry = it.next();
            //queryStringBuilder.append(prefix).append(entry.getKey()).append('=').append(entry.getValue());
            queryStringBuilder.append(prefix).append(entry.getKey().replace(".", "__")).append('=')
                    .append(entry.getValue());
            if (it.hasNext()) {
                queryStringBuilder.append('&');
            }
        }
        return queryStringBuilder.toString();
    }

    /**
     * Http Basic? Header?.
     */
    public static String encodeHttpBasic(String userName, String password) {
        String encode = userName + ":" + password;
        return "Basic " + Encodes.encodeBase64(encode.getBytes());
    }
}