numbean.java

j2ee关于BEANS的多个例子

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class NumBean extends JPanel implements ActionListener
{
	JLabel lab1,lab2;
	JTextField txt1,txt2;
	JButton btnOk;
	GridBagLayout gbl=new GridBagLayout();
	GridBagConstraints gbc=new GridBagConstraints();
	NumListener nl;
	
	public NumBean()
	{
		lab1=new JLabel("请输入第一个数: ");
		lab2=new JLabel("请输入第二个数: ");
		txt1=new JTextField(5);
		txt2=new JTextField(5);
		btnOk=new JButton("Caculate");
		
		setLayout(gbl);
		
		gbc.anchor=gbc.NORTHWEST;
		gbc.gridx=1;
		gbc.gridy=1;
		gbl.setConstraints(lab1,gbc);
		add(lab1);
		gbc.anchor=gbc.NORTHWEST;
		gbc.gridx=2;
		gbc.gridy=1;
		gbl.setConstraints(txt1,gbc);
		add(txt1);
		gbc.anchor=gbc.NORTHWEST;
		gbc.gridx=1;
		gbc.gridy=2;
		gbl.setConstraints(lab2,gbc);
		add(lab2);
		gbc.anchor=gbc.NORTHWEST;
		gbc.gridx=2;
		gbc.gridy=2;
		gbl.setConstraints(txt2,gbc);
		add(txt2);
		gbc.anchor=gbc.CENTER;
		gbc.gridwidth=2;
		gbc.gridx=1;
		gbc.gridy=3;
		gbl.setConstraints(btnOk,gbc);
		add(btnOk);
		btnOk.addActionListener(this);
		
	}
	
	public void actionPerformed(ActionEvent evt)
	{
		Object obj=evt.getSource();
		if (obj==btnOk)
		{
			int n1,n2;
			n1=Integer.parseInt(txt1.getText());
			n2=Integer.parseInt(txt2.getText());
			fireNumEvent(this,n1,n2);
		}
	}
	private void fireNumEvent(Object obj,int num1,int num2)
	{
		// 调用客户程序实现的 calResult
		if (nl!=null)
			nl.calResult(new NumEvent(obj,num1,num2));
	}
	
	public void removeNumListener()
	{
		nl=null;
	}
	
	public void addNumListener(NumListener nl)
	{
		this.nl=nl;
	}		
}