NSIS script for java installation

Question

I want to install Java using an NSIS script, but i have to know whether Java is installed or not in the system (Windows). based on the register keys how can we check if Java

Answer 1

Another example with online jre installer and 64/32 bit check

java min version

!define JRE_VERSION_6 "1.5"

check function

Function DetectJRE
  ;64bit jre und jdk check
  SetRegView 64
  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment" \
             "CurrentVersion"
  ;StrCmp $2 ${JRE_VERSION_6} done
  ${VersionCompare} $2 ${JRE_VERSION_6} $R0
  StrCmp $R0 "1" done

  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Development Kit" \
             "CurrentVersion"
  ;StrCmp $2 ${JRE_VERSION_6} done
  ${VersionCompare} $2 ${JRE_VERSION_6} $R0
  StrCmp $R0 "1" done

  ;32bit jre und jdk check
  SetRegView 32
  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Runtime Environment" \
             "CurrentVersion"
  ;StrCmp $2 ${JRE_VERSION_6} done
  ${VersionCompare} $2 ${JRE_VERSION_6} $R0
  StrCmp $R0 "1" done

  ReadRegStr $2 HKLM "SOFTWARE\JavaSoft\Java Development Kit" \
             "CurrentVersion"
  ;StrCmp $2 ${JRE_VERSION_6} done
  ${VersionCompare} $2 ${JRE_VERSION_6} $R0
  StrCmp $R0 "1" done


  Call GetJRE
  done:
FunctionEnd

version compare

Function VersionCompare
    !define VersionCompare `!insertmacro VersionCompareCall`

    !macro VersionCompareCall _VER1 _VER2 _RESULT
        Push `${_VER1}`
        Push `${_VER2}`
        Call VersionCompare
        Pop ${_RESULT}
    !macroend

    Exch $1
    Exch
    Exch $0
    Exch
    Push $2
    Push $3
    Push $4
    Push $5
    Push $6
    Push $7

    begin:
    StrCpy $2 -1
    IntOp $2 $2 + 1
    StrCpy $3 $0 1 $2
    StrCmp $3 '' +2
    StrCmp $3 '.' 0 -3
    StrCpy $4 $0 $2
    IntOp $2 $2 + 1
    StrCpy $0 $0 '' $2

    StrCpy $2 -1
    IntOp $2 $2 + 1
    StrCpy $3 $1 1 $2
    StrCmp $3 '' +2
    StrCmp $3 '.' 0 -3
    StrCpy $5 $1 $2
    IntOp $2 $2 + 1
    StrCpy $1 $1 '' $2

    StrCmp $4$5 '' equal

    StrCpy $6 -1
    IntOp $6 $6 + 1
    StrCpy $3 $4 1 $6
    StrCmp $3 '0' -2
    StrCmp $3 '' 0 +2
    StrCpy $4 0

    StrCpy $7 -1
    IntOp $7 $7 + 1
    StrCpy $3 $5 1 $7
    StrCmp $3 '0' -2
    StrCmp $3 '' 0 +2
    StrCpy $5 0

    StrCmp $4 0 0 +2
    StrCmp $5 0 begin newer2
    StrCmp $5 0 newer1
    IntCmp $6 $7 0 newer1 newer2

    StrCpy $4 '1$4'
    StrCpy $5 '1$5'
    IntCmp $4 $5 begin newer2 newer1

    equal:
    StrCpy $0 0
    goto end
    newer1:
    StrCpy $0 1
    goto end
    newer2:
    StrCpy $0 2

    end:
    Pop $7
    Pop $6
    Pop $5
    Pop $4
    Pop $3
    Pop $2
    Pop $1
    Exch $0
FunctionEnd

getJre

Function GetJRE
    MessageBox MB_YESNO "XXXXXX require at least Java 1.5! Do you want to download and install it now?" IDYES doInstall

    Abort
    doInstall:
    StrCpy $2 "$TEMP\Java Runtime Environment.exe"
    nsisdl::download /TIMEOUT=30000 ${JRE_URL} $2
    Pop $R0 ;Get the return value
        StrCmp $R0 "success" +3
        MessageBox MB_OK "Download failed: $R0"
        Quit
    ExecWait $2
    Delete $2  

    Call DetectJRE
FunctionEnd

if theire is something missing you will find it at nsis-wiki page