Cookie
Cookie 是指存儲在用戶本地終端上的數據,同時它是與具體的 Web 頁面或者站點相關的。Cookie 數據會自動在 Web 瀏覽器和 Web 服務器之間傳輸,也就是說 HTTP 請求發送時,會把保存在該請求域名下的所有 Cookie 值發送給 Web 服務器,因此服務器端腳本是可以讀、寫存儲在客戶端的 Cookie 的操作。
LocalStorage
在 HTML5 中,新加入了一個 localStorage 特性,這個特性主要是用來作爲本地存儲來使用的,解決了 Cookie 存儲空間不足的問題(Cookie 中每條 Cookie 的存儲空間爲 4k),localStorage 中一般瀏覽器支持的是 5M 大小,這個在不同的瀏覽器中 localStorage 會有所不同。
SessionStorage
SessionStorage 與 LocalStorage 的唯一一點區別就是 LocalStorage 屬於永久性存儲,而 SessionStorage 屬於當會話結束的時候,SessionStorage 中的鍵值對就會被清空。
UserData、GlobalStorage、Google Gear
這三種的使用都有一定的侷限性,例如
- userData 是 IE 瀏覽器專屬,它的容量可以達到 640K,這種方案可靠,不需要安裝額外插件,只不過它僅在IE下有效
- globalStorage 適用於 Firefox 2+ 的瀏覽器,類似於 IE 的 userData
- google gear 是谷歌開發出的一種本地存儲技術,需要安裝 Gear 組件
Flash ShareObject(Flash Cookie)
這種方式能能解決上面提到的 Cookie 存儲的兩個弊端,而且能夠跨瀏覽器,應該說是目前最好的本地存儲方案。不過,需要在頁面中插入一個 Flash,當瀏覽器沒有安裝 Flash 控件時就不能用了。所幸的是,沒有安裝 Flash 的用戶極少。
附:CookieUtils
package com.funtl.leeshop.commons.utils;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
/**
* Cookie 工具類
* <p>Title: CookieUtils</p>
* <p>Description: </p>
*
* @author Lusifer
* @version 1.0.0
* @date 2017/12/10 22:00
*/
public final class CookieUtils {
/**
* 得到Cookie的值, 不編碼
*
* @param request
* @param cookieName
* @return
*/
public static String getCookieValue(HttpServletRequest request, String cookieName) {
return getCookieValue(request, cookieName, false);
}
/**
* 得到Cookie的值,
*
* @param request
* @param cookieName
* @return
*/
public static String getCookieValue(HttpServletRequest request, String cookieName, boolean isDecoder) {
Cookie[] cookieList = request.getCookies();
if (cookieList == null || cookieName == null) {
return null;
}
String retValue = null;
try {
for (int i = 0; i < cookieList.length; i++) {
if (cookieList[i].getName().equals(cookieName)) {
if (isDecoder) {
retValue = URLDecoder.decode(cookieList[i].getValue(), "UTF-8");
} else {
retValue = cookieList[i].getValue();
}
break;
}
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return retValue;
}
/**
* 得到Cookie的值,
*
* @param request
* @param cookieName
* @return
*/
public static String getCookieValue(HttpServletRequest request, String cookieName, String encodeString) {
Cookie[] cookieList = request.getCookies();
if (cookieList == null || cookieName == null) {
return null;
}
String retValue = null;
try {
for (int i = 0; i < cookieList.length; i++) {
if (cookieList[i].getName().equals(cookieName)) {
retValue = URLDecoder.decode(cookieList[i].getValue(), encodeString);
break;
}
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return retValue;
}
/**
* 設置Cookie的值 不設置生效時間默認瀏覽器關閉即失效,也不編碼
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue) {
setCookie(request, response, cookieName, cookieValue, -1);
}
/**
* 設置Cookie的值 在指定時間內生效,但不編碼
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, int cookieMaxage) {
setCookie(request, response, cookieName, cookieValue, cookieMaxage, false);
}
/**
* 設置Cookie的值 不設置生效時間,但編碼
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, boolean isEncode) {
setCookie(request, response, cookieName, cookieValue, -1, isEncode);
}
/**
* 設置Cookie的值 在指定時間內生效, 編碼參數
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, int cookieMaxage, boolean isEncode) {
doSetCookie(request, response, cookieName, cookieValue, cookieMaxage, isEncode);
}
/**
* 設置Cookie的值 在指定時間內生效, 編碼參數(指定編碼)
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, int cookieMaxage, String encodeString) {
doSetCookie(request, response, cookieName, cookieValue, cookieMaxage, encodeString);
}
/**
* 刪除Cookie帶cookie域名
*/
public static void deleteCookie(HttpServletRequest request, HttpServletResponse response,
String cookieName) {
doSetCookie(request, response, cookieName, "", -1, false);
}
/**
* 設置Cookie的值,並使其在指定時間內生效
*
* @param cookieMaxage cookie生效的最大秒數
*/
private static final void doSetCookie(HttpServletRequest request, HttpServletResponse response,
String cookieName, String cookieValue, int cookieMaxage, boolean isEncode) {
try {
if (cookieValue == null) {
cookieValue = "";
} else if (isEncode) {
cookieValue = URLEncoder.encode(cookieValue, "utf-8");
}
Cookie cookie = new Cookie(cookieName, cookieValue);
if (cookieMaxage > 0)
cookie.setMaxAge(cookieMaxage);
if (null != request) {// 設置域名的cookie
String domainName = getDomainName(request);
// System.out.println(domainName);
if (!"localhost".equals(domainName)) {
cookie.setDomain(domainName);
}
}
cookie.setPath("/");
response.addCookie(cookie);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 設置Cookie的值,並使其在指定時間內生效
*
* @param cookieMaxage cookie生效的最大秒數
*/
private static final void doSetCookie(HttpServletRequest request, HttpServletResponse response,
String cookieName, String cookieValue, int cookieMaxage, String encodeString) {
try {
if (cookieValue == null) {
cookieValue = "";
} else {
cookieValue = URLEncoder.encode(cookieValue, encodeString);
}
Cookie cookie = new Cookie(cookieName, cookieValue);
if (cookieMaxage > 0)
cookie.setMaxAge(cookieMaxage);
if (null != request) {// 設置域名的cookie
String domainName = getDomainName(request);
// System.out.println(domainName);
if (!"localhost".equals(domainName)) {
cookie.setDomain(domainName);
}
}
cookie.setPath("/");
response.addCookie(cookie);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 得到cookie的域名
*/
private static final String getDomainName(HttpServletRequest request) {
String domainName = null;
String serverName = request.getRequestURL().toString();
if (serverName == null || serverName.equals("")) {
domainName = "";
} else {
serverName = serverName.toLowerCase();
serverName = serverName.substring(7);
final int end = serverName.indexOf("/");
serverName = serverName.substring(0, end);
final String[] domains = serverName.split("\\.");
int len = domains.length;
if (len > 3) {
// www.xxx.com.cn
domainName = "." + domains[len - 3] + "." + domains[len - 2] + "." + domains[len - 1];
} else if (len <= 3 && len > 1) {
// xxx.com or xxx.cn
domainName = "." + domains[len - 2] + "." + domains[len - 1];
} else {
domainName = serverName;
}
}
if (domainName != null && domainName.indexOf(":") > 0) {
String[] ary = domainName.split("\\:");
domainName = ary[0];
}
return domainName;
}
}