先抛出问题 为什么第二次从A系统请求B系统的Session发明对象没了。但是需要取出来对照，这可怎么办？
　  别急，但愿看完能帮到你

1 package com.ilas.union.bigdataPlatform.common.util; 2 3 import javax.servlet.http.HttpSession; 4 import java.util.ArrayList; 5 import java.util.UUID; 10 11 public class TokenUtli { 12 private static final String TOKEN_LIST_NAME = "tokenList"; 13 14 private static ArrayList getTokenList(HttpSession session) { 15 Object obj = session.getAttribute(TOKEN_LIST_NAME); 16 if (obj != null) { 17 return (ArrayList) obj; 18 } else { 19 ArrayList tokenList = new ArrayList(); 20 session.setAttribute(TOKEN_LIST_NAME, tokenList); 21 return tokenList; 22 } 23 } 24 25 private static void saveTokenString(String tokenStr, HttpSession session) { 26 ArrayList tokenList = getTokenList(session); 27 tokenList.add(tokenStr); 28 session.setAttribute(TOKEN_LIST_NAME, tokenList); 29 } 30 31 private static String generateTokenString(){ 32 return Long.toString(System.currentTimeMillis())+"_"+UUID.randomUUID().toString(); 33 } 34 35 36 public static String getTokenString(HttpSession session) { 37 String tokenStr = generateTokenString(); 38 saveTokenString(tokenStr, session); 39 return tokenStr; 40 } 41 42 43 44 public static boolean isTokenStringValid(String tokenStr, HttpSession session) { 45 boolean valid = false; 46 if(session != null){ 47 ArrayList tokenList = getTokenList(session); 48 if (tokenList.contains(tokenStr)) { 49 valid = true; 50 tokenList.remove(tokenStr); 51 } 52 } 53 return valid; 54 } 55 56 }