Session跨域解决方案
所谓Session跨域就是摒弃了系统（Tomcat）提供的Session，而使用自定义的类似Session的机制来保存客户端数据的一种解决方案。
如：通过设置cookie的domain来实现cookie的跨域传递。在cookie中传递一个自定义的session_id。这个session_id是客户端的唯一标记。将这个标记作为key，将客户端需要保存的数据作为value，在服务端进行保存（数据库保存或NoSQL保存）。这种机制就是Session的跨域解决。
什么跨域： 客户端请求的时候，请求的服务器，不是同一个IP，端口，域名，主机名的时候，都称为跨域。
什么是域：在应用模型，一个完整的，有独立访问路径的功能集合称为一个域。如：百度称为一个应用或系统。百度下有若干的域，如：搜索引擎（www.baidu.com），百度贴吧（tie.baidu.com），百度知道（zhidao.baidu.com），百度地图（map.baidu.com）等。域信息，有时也称为多级域名。域的划分： 以IP，端口，域名，主机名为标准，实现划分。
localhost / 127.0.0.1
使用cookie跨域共享，是session跨域的一种解决方案。
jsessionid是和servlet绑定的httpsession的唯一标记。
cookie应用 - new Cookie("", "").
request.getCookies() -> cookie[] -> 迭代找到需要使用的cookie
response.addCookie().
cookie.setDomain() - 为cookie设定有效域范围。
cookie.setPath() - 为cookie设定有效URI范围。
代码如下：
package com.sxt.controller;
import java.util.UUID;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import com.sxt.commons.utils.CookieUtils;
@Controller
public class TestController {
@RequestMapping("/test")
public String test(HttpServletRequest request, HttpServletResponse response){
String cookieName="custom_global_session_id";
String encodeString="UTF-8";
String cookieValue = CookieUtils.getCookieValue(request, cookieName, encodeString);
if(null == cookieValue || "".equals(cookieValue.trim())){
System.out.println("无cookie，生成新的cookie数据");
cookieValue = UUID.randomUUID().toString();
}
// 根据cookieValue访问数据存储，获取客户端数据。
CookieUtils.setCookie(request, response, cookieName, cookieValue, 0, encodeString);
return "/ok.jsp";
}
}
package com.sxt.commons.utils;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* Cookie 工具类
*
*/
public final class CookieUtils {
/**
* 得到Cookie的值, 不编码
*
* @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;
}
/**
* 设置Cookie的值 不设置生效时间默认浏览器关闭即失效,也不编码
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue) {
setCookie(request, response, cookieName, cookieValue, -1);
}
/**
* 设置Cookie的值 在指定时间内生效,但不编码
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, int cookieMaxage) {
setCookie(request, response, cookieName, cookieValue, cookieMaxage, false);
}
/**
* 设置Cookie的值 不设置生效时间,但编码
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, boolean isEncode) {
setCookie(request, response, cookieName, cookieValue, -1, isEncode);
}
/**
* 设置Cookie的值 在指定时间内生效, 编码参数
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, int cookieMaxage, boolean isEncode) {
doSetCookie(request, response, cookieName, cookieValue, cookieMaxage, isEncode);
}
/**
* 设置Cookie的值 在指定时间内生效, 编码参数(指定编码)
*/
public static void setCookie(HttpServletRequest request, HttpServletResponse response, String cookieName,
String cookieValue, int cookieMaxage, String encodeString) {
doSetCookie(request, response, cookieName, cookieValue, cookieMaxage, encodeString);
}
/**
* 删除Cookie带cookie域名
*/
public static void deleteCookie(HttpServletRequest request, HttpServletResponse response,
String cookieName) {
doSetCookie(request, response, cookieName, "", -1, false);
}
/**
* 设置Cookie的值，并使其在指定时间内生效
*
* @param cookieMaxage cookie生效的最大秒数
*/
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) {// 设置域名的cookie
String domainName = getDomainName(request);
if (!"localhost".equals(domainName)) {
cookie.setDomain(domainName);
}
}
cookie.setPath("/");
response.addCookie(cookie);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 设置Cookie的值，并使其在指定时间内生效
*
* @param cookieMaxage cookie生效的最大秒数
*/
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) {// 设置域名的cookie
String domainName = getDomainName(request);
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;
// 获取完整的请求URL地址。
String serverName = request.getRequestURL().toString();
if (serverName == null || serverName.equals("")) {
domainName = "";
} else {
serverName = serverName.toLowerCase();
if (serverName.startsWith("http://")){
serverName = serverName.substring(7);
} else if (serverName.startsWith("https://")){
serverName = serverName.substring(8);
}
final int end = serverName.indexOf("/");
// .test.com www.test.com.cn/sso.test.com.cn/.test.com.cn spring.io/xxxx/xxx
serverName = serverName.substring(0, end);
final String[] domains = serverName.split("\\.");
int len = domains.length;
if (len > 3) {
domainName = "." + domains[len - 3] + "." + domains[len - 2] + "." + domains[len - 1];
} else if (len <= 3 && len > 1) {
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;
}
}
在host文件配置如下：
192.168.31.214 test1.mss.ctc.com
192.168.31.214 test2.mss.ctc.com
通过浏览器访问地址 http://test2.mss.ctc.com/test 和 http://test1.mss.ctc.com/test 是否相同的cookie值
