I define a system variable CATALINA_HOME which refers to tomcat installation directory in my OS system(windows 7 ultimate 64 bit), now I want to get it by java, my code is below:
System.out.println(System.getenv("CATALINA_HOME"));
it returns null, I am pretty sure this variable exists in my system, I type set catalina_home in cmd console, it shows exactly the value assigned to it.
So why can’t I get it, or is there other way to get system env variable?
PS: the below are all variables retrieved by System.getenv().
Map<String, String> env = System.getenv();
for (String key : env.keySet())
{
System.out.println(key + ":" + env.get(key));
}
System.out.println(System.getenv("CATALINA_HOME"));
output:
USERPROFILE:C:Userschorusheng ProgramData:C:ProgramData PATHEXT:.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC JAVA_HOME:C:Program FilesJavajdk1.6.0_20 ProgramFiles(x86):C:Program Files (x86) TEMP:C:UsersCHORUS~1AppDataLocalTemp SystemDrive:C: ProgramFiles:C:Program Files Path:C:/Program Files (x86)/Java/jre7/bin/client;C:/Program Files (x86)/Java/jre7/bin;C:/Program Files (x86)/Java/jre7/lib/i386;C:Program Files (x86)NVIDIA CorporationPhysXCommon;d:Program Files (x86)KOUTONCTBS Standard Client;C:Program Files (x86)PC Connectivity Solution;D:oracleproduct11.2.0dbhome_1bin;C:Program Files (x86)Common FilesNetSarang;C:Windowssystem32;C:Windows;C:WindowsSystem32Wbem;C:WindowsSystem32WindowsPowerShellv1.0;C:Program FilesIntelWiFibin;C:Program FilesCommon FilesIntelWirelessCommon;C:Program Files (x86)EgisTec BioExcess;C:Program Files (x86)EgisTec BioExcessx64;C:Program Files (x86)Common FilesThunder NetworkKanKanCodecs;d:Program Files (x86)TencentQQPCMgr6.6.2150.401;D:Program Files (x86)TortoiseSVNbin;d:Program Files (x86)DigiWin OpenVPNbin;d:Program Files (x86)TencentQQPCMgr6.6.2150.401;F:chegaeclipsej2ee3.7; HOMEDRIVE:C: DYNA_HOME:E:plm PROCESSOR_REVISION:2502 USERDOMAIN:chorus ALLUSERSPROFILE:C:ProgramData ProgramW6432:C:Program Files PROCESSOR_IDENTIFIER:Intel64 Family 6 Model 37 Stepping 2, GenuineIntel SESSIONNAME:Console TMP:C:UsersCHORUS~1AppDataLocalTemp CommonProgramFiles:C:Program FilesCommon Files CLASSPATH:.;C:Program FilesJavajdk1.6.0_20libdt.jar;C:Program FilesJavajdk1.6.0_20libtools.jar; LOGONSERVER:\CHORUS PROCESSOR_ARCHITECTURE:AMD64 FP_NO_HOST_CHECK:NO OS:Windows_NT HOMEPATH:Userschorusheng PROCESSOR_LEVEL:6 CommonProgramW6432:C:Program FilesCommon Files 1830B7BD-F7A3-4c4d-989B-C004DE465EDE:f44:431b280 LOCALAPPDATA:C:UserschorushengAppDataLocal COMPUTERNAME:CHORUS windir:C:Windows SystemRoot:C:Windows asl.log:Destination=file NUMBER_OF_PROCESSORS:4 USERNAME:chorusheng PUBLIC:C:UsersPublic PSModulePath:C:Windowssystem32WindowsPowerShellv1.0Modules CommonProgramFiles(x86):C:Program Files (x86)Common Files ComSpec:C:Windowssystem32cmd.exe APPDATA:C:UserschorushengAppDataRoaming null
as we can see, the last line is null which is the value of CATALINA_HOME variable.
PS: my tomcat is not an installation edition.
Answer
Possible reasons:
You’ve used
set CATALINA_HOMEin a command prompt. That makes this variable local to this window. It should be visible to processes started from this command prompt but nowhere else. UseMy Computer > Advanced > Environment Variablesto make a variable visible to all new processes.The process which tries to read the variable is already running. Restart it.
Note: That could be the IDE if you start Tomcat from the debugger or the standalone Tomcat process when you start it from the command line.
The start script of Tomcat unsets the variable before it invokes
java.exeTomcat unsets the variable in it’s Java code.