requesthelper.java

来自「一个实用工具类」· Java 代码 · 共 149 行

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.web.helper;

import java.util.Iterator;
import java.util.Map;
import java.util.Set;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;

import org.butor.helper.URLEncoder;
import org.butor.log.Log;

/**
 * Various helper methods to use on an ButorServletRequest.
 * 
 * @author 	mateusfi
 */
public abstract class RequestHelper {

	/**
	 * Gets a cookie by its name from the request.
	 * 
	 * @param request 
	 * @param name Name of the cookie to get.
	 * @return The found cookie or null if not found.
	 */
	public static Cookie getCookie(HttpServletRequest request, String name) {
		if (request == null) {
			throw new NullPointerException("request can't be null");
		}
		if (name == null) {
			throw new NullPointerException("name can't be null");
		}
		
		Cookie[] cookies = request.getCookies();
		if (cookies == null) {
			return null;
		}
		
		for (int i = 0; i < cookies.length; i++) {
			Cookie cookie = cookies[i];
			if (cookie != null) {
				if (cookie.getName().equals(name)) {
					return cookie;
				}
			}
		}
		
		return null;
	}

	/**
	 * Builds an absolute URL using the information of the request and
	 * an context-relative path.
	 * 
	 * @param request 
	 * @param path path to include in the URL, can be null
	 * @param contextRelative if true, the URL will contain the current contextPath
	 */
	public static String buildUrl(HttpServletRequest request, String path, boolean contextRelative) {
		return buildUrl(request, path, contextRelative, null);
	}

	/**
	 * Builds an absolute URL using the information of the request and
	 * an context-relative path.
	 * 
	 * @param request 
	 * @param path path to include in the URL, can be null
 	 * @param contextRelative if true, the URL will contain the current contextPath
	 * @param params map of parameters to append to URL.  Map key is a String and map value could be either
	 * 	a String of a String[].
	 */	
	public static String buildUrl(HttpServletRequest request, String path, boolean contextRelative, Map params) {
		if (request == null) {
			Log.logStr(RequestHelper.class, Log.LOG_TYPE_WARN, "buildUrl", "request is null, can't build URL");
			return null;
		}

		// If the server port correspond to the default according to scheme, do not 
		// include it in the URL otherwise this causes some trouble for the login process.
		String port = "";
		if (("http".equals(request.getScheme()) && request.getServerPort() != 80) 
			|| ("https".equals(request.getScheme()) && request.getServerPort() != 443)) {
			port = ":" + request.getServerPort();
		}
		
		StringBuffer url = new StringBuffer();
		url.append(request.getScheme());
		url.append("://");
		url.append(request.getServerName());
		url.append(port);

		if (contextRelative) {
			url.append(request.getContextPath());
		}
		
		if (path != null) {
			url.append(path);
		}
		
		if (params != null) {
			if (params.size() > 0) {
				url.append("?");
				
				StringBuffer queryString = new StringBuffer();
				
				Set keys = params.keySet();
				for (Iterator it = keys.iterator(); it.hasNext(); ) {
					String key = (String)it.next();
					Object o = params.get(key);
					
					String value = "";
					// If map value is of type String[], we must iterate
					// into it and create multiple keys having the same name.
					if (o instanceof String[]) {
						String[] valueArray = (String[])o;
						for (int i = 0; i < valueArray.length; i++) {
							appendParameter(queryString, key, valueArray[i]);
						}
					} else {
						appendParameter(queryString, key, params.get(key).toString());
					}
				}
				
				url.append(queryString.toString());
			}
		}
		
		return url.toString();
	}
	
	private static void appendParameter(StringBuffer queryString, String name, String value) {
		if (queryString.length() > 0) {
			queryString.append("&");
		}
		queryString.append(name + "=" + URLEncoder.encode(value));
	}
}