ServletContextAttibuteListener.java监听器
@WebListener()
public class MyServletContextAttributeListener implements ServletContextAttributeListener {
@Override
public void attributeAdded(ServletContextAttributeEvent servletContextAttributeEvent) {
System.out.println("添加了"+servletContextAttributeEvent.getName());//添加域中的name
System.out.println("添加了"+servletContextAttributeEvent.getValue());//添加域中的value
}
@Override
public void attributeRemoved(ServletContextAttributeEvent servletContextAttributeEvent) {
System.out.println("删除了"+servletContextAttributeEvent.getName());//添加域中的name
System.out.println("删除了"+servletContextAttributeEvent.getValue());//添加域中的value
}
@Override
public void attributeReplaced(ServletContextAttributeEvent servletContextAttributeEvent) {
System.out.println("修改了"+servletContextAttributeEvent.getName());//获得修改前的name
System.out.println("修改了"+servletContextAttributeEvent.getValue());//获得修改前的value
}
}
TestServletContextAttributeListener.java用来模拟添加和删除数据
@WebServlet(name = "TestServletContextAttributeListener ",urlPatterns = "/TestServletContextAttributeListener")
public class TestServletContextAttributeListener extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
ServletContext servletContext = this.getServletContext();
servletContext.setAttribute("name","xiaoming");//添加
servletContext.setAttribute("name","xiaozhu");//修改
servletContext.removeAttribute("name");//移除
}
}