普通的(de)Web開發，都(dou)是把sessionid保存在(zai)cookie中傳(chuan)遞的(de)。

不管是java還是php，服務端的(de)會在(zai)response的(de)header中加上(shang)Set-Cookie

1. Response Headers
2. Content-Type:application/json;charset=UTF-8
3. Date:Mon, 02 Apr 2018 16:02:42 GMT
4. Set-Cookie:JSESSIONID=781C7F500DFA24D663BA243A4D9044BC;path=/yht;HttpOnly

瀏覽器(qi)的請求也會(hui)在header中(zhong)加上

1. Request Headers
2. Accept:*/*
3. Accept-Encoding:gzip, deflate, br
4. Accept-Language:zh-CN,zh;q=0.8
5. Cache-Control:no-cache
6. Connection:keep-alive
7. Content-Length:564
8. content-type:application/json
9. Cookie:JSESSIONID=781C7F500DFA24D663BA243A4D9044BC;path=/yht;HttpOnly

通(tong)過(guo)這個(ge)sessionid就能使瀏覽(lan)器端和服(fu)務端保持會(hui)話(hua)，使瀏覽(lan)器端保持登(deng)錄狀態

但是，微信(xin)小(xiao)程序不(bu)(bu)能保存(cun)Cookie，導致每次wx.request到服(fu)務端(duan)都會(hui)創建一個(ge)新的會(hui)話，小(xiao)程序端(duan)就(jiu)不(bu)(bu)能保持登(deng)錄狀態了(le)

簡單的處理方法如(ru)下(xia)：

 1、把服務端response的Set-Cookie中(zhong)的值(zhi)保(bao)存到Storage中(zhong)

1. wx.request({
2. url: path,
3. method:method,
4. header: header,
5. data:data,
6. success:function(res){
7. if(res && res.header && res.header['Set-Cookie']){
8. wx.setStorageSync('cookieKey', res.header['Set-Cookie']);//保存Cookie到Storage
9. }
10. },
11. fail:fail
12. })
13. wx.request再從Storage中取出Cookie,封裝到header中
14. let cookie = wx.getStorageSync('cookieKey');
15. let path=conf.baseurl+url;
16. let header = { };
17. if(cookie){
18. header.Cookie=cookie;
19. }
20.  
21. wx.request({
22. url: path,
23. method:method,
24. header: header,
25. data:data,
26. success:success,
27. fail:fail
28. })