Java Tutorial/Servlet/web.xml
Содержание
Define welcome files for web application
<?xml version="1.0" encoding="UTF-8"?>
<web-app
xmlns="http://java.sun.ru/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.ru/xml/ns/javaee http://java.sun.ru/xml/ns/javaee/web-app_2_5.xsd"
version="2.5">
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
Servlet Map URL in web.XML
<HTML>
<HEAD>
<TITLE>Introductions</TITLE>
</HEAD>
<BODY>
<FORM METHOD=GET ACTION="Hello.do">
If you don"t mind me asking, what is your name?
<INPUT TYPE=TEXT NAME="name"><P>
<INPUT TYPE=SUBMIT>
</FORM>
</BODY>
</HTML>
Servlet Pass Init Value in Web XML
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class MyServlet extends HttpServlet {
int count;
public void init() throws ServletException {
String initial = getInitParameter("initial");
try {
count = Integer.parseInt(initial);
}
catch (NumberFormatException e) {
count = 0;
}
}
public void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/plain");
PrintWriter out = res.getWriter();
count++;
out.println("Since loading (and with a possible initialization");
out.println("parameter figured in), this servlet has been accessed");
out.println(count + " times.");
}
}
Servlet Web XML Context Init Parameter
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class MyServlet extends HttpServlet {
private String dbName="";
private String dbPassword="";
public void init(ServletConfig config) throws ServletException {
super.init(config);
ServletContext context = getServletContext();
dbName = context.getInitParameter("name");
dbPassword = context.getInitParameter("password");
}
public void doGet (HttpServletRequest req, HttpServletResponse res) throws IOException
{
ServletOutputStream out = res.getOutputStream();
res.setContentType("text/html");
out.println("<html><head><title>Basic Servlet</title></head>");
out.println("<body>Database username is <b>" + dbName);
out.println("</b><br>Database password is <b>" + dbPassword + "</b>");
out.println("</body></html>");
}
}
Set error page in web.xml
<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.ru/dtd/web-app_2_3.dtd">
<web-app>
<error-page>
<error-code>
404
</error-code>
<location>
/404.html
</location>
</error-page>
</web-app>
Set Servlet ContextListener in web.XML
import javax.servlet.*;
import javax.servlet.http.*;
public class MyServlet implements ServletContextListener {
public void contextInitialized(ServletContextEvent e) {
// Connection con = // create connection
// e.getServletContext().setAttribute("con", con);
System.out.println("contextInitialized(ServletContextEvent e)");
}
public void contextDestroyed(ServletContextEvent e) {
// Connection con =
// (Connection) e.getServletContext().getAttribute("con");
//try { con.close(); }
//catch (SQLException ignored) { } // close connection
System.out.println("contextDestroyed(ServletContextEvent e)");
}
}
