设置按钮的位置

import java.awt.BorderLayout;
import java.awt.Container;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Java extends JFrame {

 JPanel pabelnorth,pabelsouth,pabelwest,pabeleast,pabelcenter;
 JButton buttonnorth,buttonsouth,buttonwest,buttoneast,buttoncenter;
 Container cont;
 public Java(){
  super("面板");
  
  buttonnorth = new JButton("北");
  buttonsouth = new JButton("南");
  buttonwest = new JButton("西");
  buttoneast = new JButton("东");
  buttoncenter = new JButton("中");
  
  pabelnorth = new JPanel();
  pabelnorth.add(buttonnorth);
  
  pabelsouth = new JPanel();
  pabelsouth.add(buttonsouth);
  
  pabelwest = new JPanel();
  pabelwest.add(buttonwest);
  
  pabeleast = new JPanel();
  pabeleast.add(buttoneast);
  
  pabelcenter = new JPanel();
  pabelcenter.add(buttoncenter);
  
  cont = this.getContentPane();
  
  cont.add(pabelnorth,BorderLayout.NORTH);
  cont.add(pabelsouth,BorderLayout.SOUTH);
  cont.add(pabelwest,BorderLayout.WEST);
  cont.add(pabeleast,BorderLayout.EAST);
  cont.add(pabelcenter,BorderLayout.CENTER);
  
  this.setVisible(true);
  this.setSize(300,150);
  this.validate();
  
 }
 public static void main(String[] args) {
  new Java();

 }

}