java - 防止旧版本安装在新版本之上

Question

我想设置一些版本验证，以防止最终用户在新版本之上安装旧版本。前任。安装版本 3 后阻止安装版本 1。最好的方法是什么？

Answer 1

您可以将“运行脚本”操作添加到安装程序的“启动”节点，以验证已安装的版本。

以下代码片段演示了如何针对较新的版本进行验证(如果它们是简单整数):

// The value returned by context.getInstallationDirectory() will be the last 
// installation directory if the user has already installed the application
ApplicationRegistry.ApplicationInfo applicationInfo =
    ApplicationRegistry.getApplicationInfoByDir(context.getInstallationDirectory());

if (applicationInfo == null) {
  // The application has never been installed before
    return true;
}

if (Integer.parseInt(applicationInfo.getVersion()) > 
   Integer.parseInt(context.getVersion())) {
    Util.showErrorMessage("A more recent version has already been" +
    " installed in this directory");
    // By returning "false", the action will fail and the installer will quit.
    // Note that you have to set the "Failure strategy" property of your 
// "Run script" action to "Quit on error", otherwise the installer will continue.
    return false;
} else {
    return true;
}