[OT] Determinare se Java è installato in setup della propria applicazione

[PAC_84]

Salve a tutti,
ho creato un pacchetto di installazione con un tool automatico createinstall free. Poichè la mia è un apllicazione java vorrei sapere se c'è modo di verificare se nel pc in cui vado ad installare la mia applicazione c'è un jre... come si fa? qualcuno può aiutarmi?
Grazie mille

[pallinopinco]

In NSIS si fa una cosa del genere:

Function DetectJRE
  Exch $0    ; Get version requested  
        ; Now the previous value of $0 is on the stack, and the asked for version of JDK is in $0
  Push $1    ; $1 = Java version string (ie 1.5.0)
  Push $2    ; $2 = Javahome
  Push $3    ; $3 and $4 are used for checking the major/minor version of java
  Push $4
  MessageBox MB_OK "Detecting JRE"
  ReadRegStr $1 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment" "CurrentVersion"
  MessageBox MB_OK "Read : $1"
  StrCmp $1 "" DetectTry2
  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment\$1" "JavaHome"
  MessageBox MB_OK "Read 3: $2"
  StrCmp $2 "" DetectTry2
  Goto GetJRE
 
DetectTry2:
  ReadRegStr $1 HKLM "SOFTWARE\JavaSoft\Java Development Kit" "CurrentVersion"
  MessageBox MB_OK "Detect Read : $1"
  StrCmp $1 "" NoFound
  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Development Kit\$1" "JavaHome"
  MessageBox MB_OK "Detect Read 3: $2"
  StrCmp $2 "" NoFound
 
GetJRE:
; $0 = version requested. $1 = version found. $2 = javaHome
  MessageBox MB_OK "Getting JRE"
  IfFileExists "$2\bin\java.exe" 0 NoFound
  StrCpy $3 $0 1            ; Get major version. Example: $1 = 1.5.0, now $3 = 1
  StrCpy $4 $1 1            ; $3 = major version requested, $4 = major version found
  MessageBox MB_OK "Want $3 , found $4"
  IntCmp $4 $3 0 FoundOld FoundNew
  StrCpy $3 $0 1 2
  StrCpy $4 $1 1 2            ; Same as above. $3 is minor version requested, $4 is minor version installed
  MessageBox MB_OK "Want $3 , found $4" 
  IntCmp $4 $3 FoundNew FoundOld FoundNew
 
NoFound:
  MessageBox MB_OK "JRE not found"
  Push "0"
  Goto DetectJREEnd
 
FoundOld:
  MessageBox MB_OK "JRE too old: $3 is older than $4"
;  Push ${TEMP2}
  Push "-1"
  Goto DetectJREEnd  
FoundNew:
  MessageBox MB_OK "JRE is new: $3 is newer than $4"
 
  Push "$2\bin\java.exe"
;  Push "OK"
;  Return
   Goto DetectJREEnd
DetectJREEnd:
    ; Top of stack is return value, then r4,r3,r2,r1
    Exch    ; => r4,rv,r3,r2,r1,r0
    Pop $4    ; => rv,r3,r2,r1r,r0
    Exch    ; => r3,rv,r2,r1,r0
    Pop $3    ; => rv,r2,r1,r0
    Exch     ; => r2,rv,r1,r0
    Pop $2    ; => rv,r1,r0
    Exch    ; => r1,rv,r0
    Pop $1    ; => rv,r0
    Exch    ; => r0,rv
    Pop $0    ; => rv 
FunctionEnd 

Non dovrebbe essere difficile portare i controlli sul Registry (una volta note le chiavi) nel tuo sistema di installazione.