JButton jb = new JButton();
actionPerformed{
if(jb == e.getSource()
}

用匿名内部类的方法测试。
JButton backButton = new JButton();
backButton.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("backButton如果被点 击，就输出这句话。");
}
});