import java.awt.Insets;

 import javax.swing.JFrame;

 public class FrameTitleBarLength {

     public static void main(String[] args) {

         JFrame frame = new JFrame("获取标题栏大小");

         frame.setBounds(104, 104, 1, 26);

         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

         frame.setVisible(true);

         Insets inset = frame.getInsets();

         System.out.println(inset);

         System.out.println(inset.bottom);

     }

 }