php的全局变量

php的全局变量

1.$是php的一个全局变量组，在一个脚本作用域内都可以使用

打印的结果如下：

D:\WWW.php:2:

array (size=8)
  '_GET' => 
    array (size=0)
      empty
  '_POST' => 
    array (size=0)
      empty
  '_COOKIE' => 
    array (size=2)
      'sugstore' => string '0' (length=1)
      'baikeVisitId' => string '8d420959-b540-4e7e-a145-9f73bdb16b13' (length=36)
  '_FILES' => 
    array (size=0)
      empty
  '_SERVER' => 
    array (size=80)
      'ALLUSERSPROFILE' => string 'C:ProgramData' (length=14)
      'APPDATA' => string 'C:UsersjAppDataRoaming' (length=26)
      'CommonProgramFiles' => string 'C:Program FilesCommon Files' (length=29)
      'CommonProgramFiles(x86)' => string 'C:Program Files (x86)Common Files' (length=35)
      'CommonProgramW6432' => string 'C:Program FilesCommon Files' (length=29)
      'COMPUTERNAME' => string 'DESKTOP-CCCARJ6' (length=15)
      'ComSpec' => string 'C:Windowssystem32cmd.exe' (length=27)
      'DriverData' => string 'C:WindowsSystem32DriversDriverData' (length=38)
      'HOMEDRIVE' => string 'C:' (length=2)
      'HOMEPATH' => string 'Usersj' (length=8)
      'LOCALAPPDATA' => string 'C:UsersjAppDataLocal' (length=24)
      'LOGONSERVER' => string '\DESKTOP-CCCARJ6' (length=17)
      'NUMBER_OF_PROCESSORS' => string '8' (length=1)
      'NVIDIAWHITELISTED' => string '0x01' (length=4)
      'OneDrive' => string 'C:UsersjOneDrive' (length=19)
      'OS' => string 'Windows_NT' (length=10)
      'Path' => string 'C:WindowsSystem32;D:node;d:Program Files (x86)Tencent΢��web�����߹���dll;C:UsersjAppDataLocalProgramsPythonPython310Scripts;C:UsersjAppDataLocalProgramsPythonPython310;C:UsersjAppDataLocalMicrosoftWindowsApps;C:UsersjAppDataLocalProgramsMicrosoft VS Codebin;d:Program FilesJetBrainsPyCharm 2021.3.2bin;D:phpstudy_proExtensionsMySQL5.7.26bin;C:UsersjAppDataRoamingnpm' (length=418)
      'PATHEXT' => string '.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC' (length=53)
      'PROCESSOR_ARCHITECTURE' => string 'AMD64' (length=5)
      'PROCESSOR_IDENTIFIER' => string 'Intel64 Family 6 Model 60 Stepping 3, GenuineIntel' (length=50)
      'PROCESSOR_LEVEL' => string '6' (length=1)
      'PROCESSOR_REVISION' => string '3c03' (length=4)
      'ProgramData' => string 'C:ProgramData' (length=14)
      'ProgramFiles' => string 'C:Program Files' (length=16)
      'ProgramFiles(x86)' => string 'C:Program Files (x86)' (length=22)
      'ProgramW6432' => string 'C:Program Files' (length=16)
      'PSModulePath' => string 'C:Program FilesWindowsPowerShellModules;C:Windowssystem32WindowsPowerShellv1.0Modules' (length=93)
      'PUBLIC' => string 'C:UsersPublic' (length=15)
      'PyCharm' => string 'd:Program FilesJetBrainsPyCharm 2021.3.2bin;' (length=48)
      'SHIM_MCCOMPAT' => string '0x810000001' (length=11)
      'SystemDrive' => string 'C:' (length=2)
      'SystemRoot' => string 'C:Windows' (length=10)
      'TEMP' => string 'C:UsersjAppDataLocalTemp' (length=29)
      'TMP' => string 'C:UsersjAppDataLocalTemp' (length=29)
      'USERDOMAIN' => string 'DESKTOP-CCCARJ6' (length=15)
      'USERDOMAIN_ROAMINGPROFILE' => string 'DESKTOP-CCCARJ6' (length=15)
      'USERNAME' => string 'j' (length=1)
      'USERPROFILE' => string 'C:Usersj' (length=10)
      'windir' => string 'C:Windows' (length=10)
      'WXDRIVE_START_ARGS' => string '--wxdrive-setting=0 --disable-gpu --disable-software-rasterizer --enable-features=NetworkServiceInProcess' (length=105)
      'HTTP_COOKIE' => string 'sugstore=0; baikeVisitId=8d420959-b540-4e7e-a145-9f73bdb16b13' (length=61)
      'HTTP_ACCEPT_LANGUAGE' => string 'zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6' (length=47)
      'HTTP_ACCEPT_ENCODING' => string 'gzip, deflate, br' (length=17)
      'HTTP_SEC_FETCH_DEST' => string 'document' (length=8)
      'HTTP_SEC_FETCH_USER' => string '?1' (length=2)
      'HTTP_SEC_FETCH_MODE' => string 'navigate' (length=8)
      'HTTP_SEC_FETCH_SITE' => string 'none' (length=4)
      'HTTP_ACCEPT' => string 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7' (length=124)
      'HTTP_USER_AGENT' => string 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0' (length=125)
      'HTTP_UPGRADE_INSECURE_REQUESTS' => string '1' (length=1)
      'HTTP_SEC_CH_UA_PLATFORM' => string '"Windows"' (length=9)
      'HTTP_SEC_CH_UA_MOBILE' => string '?0' (length=2)
      'HTTP_SEC_CH_UA' => string '"Not_A Brand";v="8", "Chromium";v="120", "Microsoft Edge";v="120"' (length=65)
      'HTTP_CONNECTION' => string 'keep-alive' (length=10)
      'HTTP_HOST' => string 'localhost' (length=9)
      'REDIRECT_STATUS' => string '200' (length=3)
      'SERVER_NAME' => string 'localhost' (length=9)
      'SERVER_PORT' => string '80' (length=2)
      'SERVER_ADDR' => string '127.0.0.1' (length=9)
      'REMOTE_PORT' => string '63074' (length=5)
      'REMOTE_ADDR' => string '127.0.0.1' (length=9)
      'SERVER_SOFTWARE' => string 'nginx/1.15.11' (length=13)
      'GATEWAY_INTERFACE' => string 'CGI/1.1' (length=7)
      'REQUEST_SCHEME' => string 'http' (length=4)
      'SERVER_PROTOCOL' => string 'HTTP/1.1' (length=8)
      'DOCUMENT_ROOT' => string 'D:/phpstudy_pro/WWW' (length=19)
      'DOCUMENT_URI' => string '/index2.php' (length=11)
      'REQUEST_URI' => string '/index2.php' (length=11)
      'SCRIPT_NAME' => string '/index2.php' (length=11)
      'CONTENT_LENGTH' => string '' (length=0)
      'CONTENT_TYPE' => string '' (length=0)
      'REQUEST_METHOD' => string 'GET' (length=3)
      'QUERY_STRING' => string '' (length=0)
      'PATH_TRANSLATED' => string 'D:/phpstudy_pro/WWW' (length=19)
      'PATH_INFO' => string '' (length=0)
      'SCRIPT_FILENAME' => string 'D:/phpstudy_pro/WWW/index2.php' (length=30)
      'FCGI_ROLE' => string 'RESPONDER' (length=9)
      'PHP_SELF' => string '/index2.php' (length=11)
      'REQUEST_TIME_FLOAT' => float 1702975573.7174
      'REQUEST_TIME' => int 1702975573
  '_ENV' => 
    array (size=0)
      empty
  '_REQUEST' => 
    array (size=0)
      empty
  'GLOBALS' => 
&array<
可以看出包含的有_GET、_POST、_COOKIE、_FILES、_SERVER、_ENV
_REQUEST、GLOBALS等数据。那么例如我们把get、cookie等添加数据是不
是也会在$GLOBALS中显示呢？如下图可以看到是可以的。那么$GLOBALS就是
这些全局函数的一个数据组，当然也可以自定义全局变量。

2.$自定义全局变量的使用php超全局变量，如下图可以看到在函数外面定义变量$x

和$y,在函数里面可以用$调用相加获得全局变量$z.

3. 声明全局,声明后，给变量赋值，在php作用域内，再次声明

就可以使用了。

4.$_GET一般是url传参php超全局变量，或者=”get”传参

5.$_POST不显示在url中可以js的post、=”post”提交、或者curl的

post请求。

6.$和$多用于用户身份的保存（网站的登录状态的判断）,

$的值可以在控制台看到（存储在客户端php超全局变量php的全局变量php的全局变量，不安全），$在控

制台看不到（存储在服务器端比较安全），

7.$,存储文件信息

8.$会接收到$_GET和$_POST的数据（部分开源的框架会重写

$）

9.$是包含头部信息、路径信息、脚本位置等信息的全局变量

10.$_ENY是服务器的环境变量的数组