如何将字符串参数传递给使用Apache Commons Exec启动的可执行文件?

I need to pipe a text argument to the stdin of a command launched with Apache Commons Exec (for the curious, the command is gpg and the argument is the passphrase to the keystore; gpg does not have an argument to provide the passphrase explicitly, only to accept it from stdin).I need to pipe a text argument to the stdin of