Java Servlet:强制 init 在 Payara 服务器启动时创建数据对象?
Java Servlet: Force init to create data object on Payara server start?
我正在寻找一种在第一次请求之前在我的 java servlet(在 Payara 上)中生成数据对象的方法,因为创建的数据对象需要一些时间来解析其他网站(大约 4 秒) ).
我认为设置
就足够了
@WebServlet(urlPatterns = "/reports/*", loadOnStartup = 1)
在payara server启动的时候强制servlet容器初始化(基于http://www.codejava.net/java-ee/servlet/webservlet-annotation-examples)。但是,它不起作用。我仍然有第一个请求延迟 4 秒,后续请求没有延迟。以下代码有效,问题只是第一个请求的延迟。
@WebServlet(urlPatterns = "/reports/*", loadOnStartup = 1)
public class SingleReportServlet extends HttpServlet {
ReportData m_myData;
@Override
public void init() throws ServletException {
m_myData = new ReportData(); //This takes about 4 seconds, once
System.out.println("My servlet has been initialized");
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String requestPath = request.getPathInfo();
String[] components = requestPath.split("/");
String requestedData = components[components.length-1].trim().toUpperCase();
String report = m_myData.getFullReport(requestedData, Locale.GERMAN, DisplayType.HTML_PARTIAL);
String headline = "Report for "+requestedData;
System.out.println(headline);
System.out.println(report);
request.setAttribute("headline", headline);
request.setAttribute("report", report);
request.getRequestDispatcher("/WEB-INF/singleReport.jsp").forward(request, response);
}
}
与其让 ReportData
在 servlet init
方法中初始化,我建议您使用 ServletContextListener
例如
@WebListener
public class ServletContextListenerImpl implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent sce) {
ReportData m_myData = new ReportData ();
System.out.println("My ServletContextListenerImpl has been initialized");
// then add to your session for later use
sce.getServletContext().setAttribute("RDATA", m_myData);
}
..
}
我正在寻找一种在第一次请求之前在我的 java servlet(在 Payara 上)中生成数据对象的方法,因为创建的数据对象需要一些时间来解析其他网站(大约 4 秒) ).
我认为设置
就足够了@WebServlet(urlPatterns = "/reports/*", loadOnStartup = 1)
在payara server启动的时候强制servlet容器初始化(基于http://www.codejava.net/java-ee/servlet/webservlet-annotation-examples)。但是,它不起作用。我仍然有第一个请求延迟 4 秒,后续请求没有延迟。以下代码有效,问题只是第一个请求的延迟。
@WebServlet(urlPatterns = "/reports/*", loadOnStartup = 1)
public class SingleReportServlet extends HttpServlet {
ReportData m_myData;
@Override
public void init() throws ServletException {
m_myData = new ReportData(); //This takes about 4 seconds, once
System.out.println("My servlet has been initialized");
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String requestPath = request.getPathInfo();
String[] components = requestPath.split("/");
String requestedData = components[components.length-1].trim().toUpperCase();
String report = m_myData.getFullReport(requestedData, Locale.GERMAN, DisplayType.HTML_PARTIAL);
String headline = "Report for "+requestedData;
System.out.println(headline);
System.out.println(report);
request.setAttribute("headline", headline);
request.setAttribute("report", report);
request.getRequestDispatcher("/WEB-INF/singleReport.jsp").forward(request, response);
}
}
与其让 ReportData
在 servlet init
方法中初始化,我建议您使用 ServletContextListener
例如
@WebListener
public class ServletContextListenerImpl implements ServletContextListener {
@Override
public void contextInitialized(ServletContextEvent sce) {
ReportData m_myData = new ReportData ();
System.out.println("My ServletContextListenerImpl has been initialized");
// then add to your session for later use
sce.getServletContext().setAttribute("RDATA", m_myData);
}
..
}