Java Tutorial/Servlet/ServletContext — различия между версиями

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м (1 версия)
 
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Текущая версия на 05:06, 1 июня 2010

Deployment Descriptor

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class WebAppProperties extends HttpServlet {
  public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException,
      IOException {
    resp.setContentType("text/html");
    PrintWriter out = resp.getWriter();
    ServletContext context = getServletContext();
    String displayName = context.getServletContextName();
    if (displayName == null) {
      displayName = "(no display-name element defined)";
    }
    out.println("<html>");
    out.println("<head>");
    out.println("<title>Web Application Properties");
    out.println("</title>");
    out.println("</head><body>");
    out.println("<h1>Web Application Properties</h2>");
    out.println("<br>Name: " + displayName);
    out.println("<br>Context: " + req.getContextPath());
    out.println("<h2><center>");
    out.println("Initialization Parameters</center></h2>");
    out.println("<br>");
    out.println("<center><table border width=80%>");
    Enumeration e = context.getInitParameterNames();
    while (e.hasMoreElements()) {
      String name = (String) e.nextElement();
      out.println("<tr>");
      out.println("<td>" + name + "</td>");
      out.println("<td>" + context.getInitParameter(name) + "</td>");
      out.println("</tr>");
    }
    out.println("</table></center>");
    out.println("</body>");
    out.println("</html>");
    out.flush();
  }
}





Get Servlet Context InitParameter

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>");
  }
}