ServletContextListener 初始化数据

容器启动的时候就向内存中初始化一部分数据：
The first: implements ServletContextListener interface.
public class LoaderInitializationSystem  implements ServletContextListener{
private static final Log log = LogFactory.getLog(LoaderInitializationSystem.class);
private static ServletContext servletContext;

public void contextInitialized(ServletContextEvent event) {
log.info("***********Loader Initalization Start********************************");

this.servletContext = event.getServletContext();
if(servletContext.getAttribute("system_params")!=null);
{
LoaderInitializationSystem loader= new LoaderInitializationSystem();
List<Employee> employess = loader.addEmployee();

servletContext.setAttribute("system_params",employess);
}

log.info("***********Loader Initalization End********************************");

}

public void contextDestroyed(ServletContextEvent event) {
contextInitialized(event);
}

public List<Employee> addEmployee(){
List<Employee> employees = new ArrayList<Employee>();

for (int i = 0; i < 10000; i++) {
Employee employee = new Employee();
employee.setName("Zhang San");
employee.setDepartmentNumber("F-A-T"+i);
employee.setCity("Shang-Hai");
employees.add(employee);
}

return employees;
}
}

 

The sendent : getServlet data:

ServletContext servletContext = getServletContext();

String result servletContext.getAttribute("system_parameter");

or

String result = pageContext.getServletContext(). getAttribute("system_parameter")

 

request.setAtrribute("result",result);

 

view jsp

 

${result}