首先需要一个操作类:
Dao1:
package demoDao;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
public class Dao1 {
public static void main(String[] args) {
JFrame jf = new JFrame();
jf.setSize(300,200);
jf.setLocation(200,200);
jf.setLayout(new FlowLayout());
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton btn = new JButton("确定");
jf.add(btn);
btn.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
System.out.println("hello!");
}
});
jf.setVisible(true);
}
}
这里创建了一个窗口和一个按钮。
下面就需要一个类去实现ServletContextListener然后在web.xml中注册:
AListener:
package demoListener; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class AListener implements ServletContextListener { @Override public void contextInitialized(ServletContextEvent sce) { System.out.println("我来了!"); } @Override public void contextDestroyed(ServletContextEvent sce) { System.out.println("我走了!"); } }
web.xml:
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
id="WebApp_ID" version="4.0">
<display-name>day041501</display-name>
<listener>
<listener-class>demoListener.AListener</listener-class>
</listener>
</web-app>
运行Dao1,点击按钮,控制台就输出了“hello”: