安装前检查Java是否存在

Question

我正在为jar应用创建一个Inno Setup安装程序.我现在要做的是在继续安装之前检查java是否存在.所以我只需要确保用户能够运行:

java -jar my-app.jar

我现在正在做的是:

[Code]

function InitializeSetup(): Boolean;
var
  ErrorCode: Integer;
  JavaInstalled : Boolean;
  Result1 : Boolean;
begin
  JavaInstalled := RegKeyExists(HKLM,'SOFTWARE\JavaSoft\Java Runtime Environment\1.6');
  if JavaInstalled then
  begin
    Result := true;
  end else
    begin
      Result1 := MsgBox('This tool requires Java Runtime Environment version 1.6 or newer to run. Please download and install the JRE and run this setup again. Do you want to download it now?',
        mbConfirmation, MB_YESNO) = idYes;
      if Result1 = false then
      begin
        Result:=false;
      end else
      begin
        Result:=false;
        ShellExec('open',
          'http://javadl.sun.com/webapps/download/AutoDL?BundleId=33787',
          '','',SW_SHOWNORMAL,ewNoWait,ErrorCode);
      end;
    end;
  end;
end;

我的问题是:

• 检查注册表是否足以确保java的主目录将在PATH中？(能够在控制台中运行"java")

• 如果安装了更高版本的java,那么注册表中的密钥是否仍然存在,或者我将不得不检查每个更高版本？

• 有没有人有更好的方式来下载java,而不仅仅是显示弹出窗口并将用户带到下载页面？

Answer 1

我希望有人发现这很有用,我所做的就是重复使用Inno Setups wiki中的一些代码来与版本作为数字进行<>比较:

{ Both DecodeVersion and CompareVersion functions where taken from the  wiki }
procedure DecodeVersion (verstr: String; var verint: array of Integer);
var
  i,p: Integer; s: string;
begin
  { initialize array }
  verint := [0,0,0,0];
  i := 0;
  while ((Length(verstr) > 0) and (i < 4)) do
  begin
    p := pos ('.', verstr);
    if p > 0 then
    begin
      if p = 1 then s:= '0' else s:= Copy (verstr, 1, p - 1);
      verint[i] := StrToInt(s);
      i := i + 1;
      verstr := Copy (verstr, p+1, Length(verstr));
    end
    else
    begin
      verint[i] := StrToInt (verstr);
      verstr := '';
    end;
  end;

end;

function CompareVersion (ver1, ver2: String) : Integer;
var
  verint1, verint2: array of Integer;
  i: integer;
begin

  SetArrayLength (verint1, 4);
  DecodeVersion (ver1, verint1);

  SetArrayLength (verint2, 4);
  DecodeVersion (ver2, verint2);

  Result := 0; i := 0;
  while ((Result = 0) and ( i < 4 )) do
  begin
    if verint1[i] > verint2[i] then
      Result := 1
    else
      if verint1[i] < verint2[i] then
        Result := -1
      else
        Result := 0;
    i := i + 1;
  end;

end;

{ Here's my code }
function InitializeSetup(): Boolean;
var
  ErrorCode: Integer;
  JavaVer : String;
  Result1 : Boolean;
begin
    RegQueryStringValue(HKLM, 'SOFTWARE\JavaSoft\Java Runtime Environment', 'CurrentVersion', JavaVer);
    Result := false;
    if Length( JavaVer ) > 0 then
    begin
        if CompareVersion(JavaVer,'1.6') >= 0 then
        begin
            Result := true;
        end;
    end;
    if Result = false then
    begin
        Result1 := MsgBox('This tool requires Java Runtime Environment v1.6 or older to run. Please download and install JRE and run this setup again.' + #13 + #10 + 'Do you want to download it now?',
          mbConfirmation, MB_YESNO) = idYes;
        if Result1 = true then
        begin
            ShellExec('open',
              'http://www.java.com/en/download/manual.jsp#win',
              '','',SW_SHOWNORMAL,ewNoWait,ErrorCode);
        end;
    end;
end;

感谢你的帮助

Answer 2

我改变了你的代码,我认为这样可以支持更新版本的Java ;-)

function InitializeSetup(): Boolean;
var
 ErrorCode: Integer;
 JavaInstalled : Boolean;
 Result1 : Boolean;
 Versions: TArrayOfString;
 I: Integer;
begin
 if RegGetSubkeyNames(HKLM, 'SOFTWARE\JavaSoft\Java Runtime Environment', Versions) then
 begin
  for I := 0 to GetArrayLength(Versions)-1 do
   if JavaInstalled = true then
   begin
    //do nothing
   end else
   begin
    if ( Versions[I][2]='.' ) and ( ( StrToInt(Versions[I][1]) > 1 ) or ( ( StrToInt(Versions[I][1]) = 1 ) and ( StrToInt(Versions[I][3]) >= 6 ) ) ) then
    begin
     JavaInstalled := true;
    end else
    begin
     JavaInstalled := false;
    end;
   end;
 end else
 begin
  JavaInstalled := false;
 end;


 //JavaInstalled := RegKeyExists(HKLM,'SOFTWARE\JavaSoft\Java Runtime Environment\1.9');
 if JavaInstalled then
 begin
  Result := true;
 end else
    begin
  Result1 := MsgBox('This tool requires Java Runtime Environment version 1.6 or newer to run. Please download and install the JRE and run this setup again. Do you want to download it now?',
   mbConfirmation, MB_YESNO) = idYes;
  if Result1 = false then
  begin
   Result:=false;
  end else
  begin
   Result:=false;
   ShellExec('open',
    'http://www.java.com/getjava/',
    '','',SW_SHOWNORMAL,ewNoWait,ErrorCode);
  end;
    end;
end;


end.