appcontextlistener.java

JSF+Hibernate+Spring三层架构的一个例子

package pizzaria;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class AppContextListener implements ServletContextListener {

   //从web.xml文件中读取Servlet上下文初始化参数,构造一个DatabaseUtil对象
  public void contextInitialized(ServletContextEvent event) {
    DatabaseUtil dbUtil = new DatabaseUtil();
    ServletContext servletContext = event.getServletContext();
    String jdbcDriver = servletContext.getInitParameter("jdbcDriver");
    String dbUrl = servletContext.getInitParameter("dbUrl");
    String dbUserName = servletContext.getInitParameter("dbUserName");
    String dbPassword = servletContext.getInitParameter("dbPassword");
    dbUtil.setJdbcDriver(jdbcDriver);
    dbUtil.setDbUrl(dbUrl);
    dbUtil.setDbUserName(dbUserName);
    dbUtil.setDbPassword(dbPassword);
    servletContext.setAttribute("DATABASE_UTIL", dbUtil);
  }

  public void contextDestroyed(ServletContextEvent event) {
    ServletContext servletContext = event.getServletContext();
    servletContext.removeAttribute("DATABASE_UTIL");
  }
}