Java之获取文件名、文件类型(文件后缀名)

public class TestSubString {

  public static void main(String[] args) {

    String fileName = "upload/20191015/20191015163150_840.pdf";
    String filePath = fileName.replace("/", "\\");
    String docOldName = filePath.substring(filePath.lastIndexOf("\\") + 1);
    System.out.println(docOldName);
  }
}