如何在生成步骤中从对象名中删除文件扩展名？

String objectName = "example.txt";
int dotIndex = objectName.lastIndexOf(".");
String fileName = objectName.substring(0, dotIndex);
String extension = objectName.substring(dotIndex + 1);
String fileNameWithoutExtension = fileName.concat(extension);

System.out.println("文件名：" + fileName);
System.out.println("扩展名：" + extension);
System.out.println("删除扩展名后的文件名：" + fileNameWithoutExtension);