ServletContext Interface |
public interface ServletContext |

The ServletContext interface declares methods that a servlet uses to communicate with its host server. The methods declared in this interface allow a servlet to obtain information about the server on which it is running.

Example: Using ServletContext

A ServletContext object is used to obtain information about the server on which a servlet is running. The ServletContext object is also used to obtain a second ServletContext object that is associated with another resource.

         import javax.servlet.*;
         import java.io.*;
         import java.util.*;
         public class ServerInfoServlet extends GenericServlet {
           String attributeName;
           public void service(ServletRequest request, ServletResponse response)
                   throws ServletException, IOException {
         response.setContentType("text/plain");
             PrintWriter pw = response.getWriter();
             // A ServletContext object is used to obtain information about
             // the server.
         ServletContext sc = getServletContext();
             pw.println("Server info is " + sc.getServerInfo());
             // Two additional attributes are added.
             sc.setAttribute("status", "OK");
             sc.setAttribute("mood", "happy");
             pw.println();
             pw.println("Server Attributes");
             Enumeration e = sc.getAttributeNames();
             while (e.hasMoreElements()) {
               attributeName = (String) e.nextElement();
               pw.println("name: " + attributeName + "  value: "
                          + sc.getAttribute(attributeName));
             }
        // The original ServletContext object can be used to obtain a
             // ServletContext of another resource
             pw.println();
             pw.println("Other resource info");
             String path = sc.getRealPath("/tmp.txt");
             ServletContext sc2 = sc.getContext(path);
             pw.println("MIME type: " + sc2.getMimeType(path));
             pw.close();
           }
         }

Finally, the tmp.txt file contains:

                blah, blah, blah

getContext() |
public ServletContext getContext(String URLpath) | Method
getContext() returns the ServletContext object for the resource at the specified path on the server. The path argument is an absolute URL beginning with "/".

getMimeType() |
public String getMimeType(String file) | Method
getMimeType() returns MIME type of the specified file or null if the MIME type cannot be ascertained. Typical return values will be "text/plain", "text/html", or "image/jpg".

getRealPath() |
public String getRealPath(String virtualPath) | Method
getRealPath() returns a String object containing the real path, in a form appropriate to the platform on which the servlet is running, corresponding to the given virtual path. An example of a virtual path might be "/blah.html".

getServerInfo() |
public String getServerInfo() | Method
getServerInfo() returns a String object containing information on the server on which the servlet is running. At a minimum, the String will contain the servlet container name and version number.

getInitParameter() |
public String getInitParameter(String name) | Method
getInitParameter() returns a String object containing the value of the specfied initialization parameter, or null if the parameter does not exist.

getInitParameterNames() |
public Enumeration getInitParameterNames() | Method
getInitParameterNames() returns a Enumeration containing the initialization parameters associated with the invoking ServletContext object

log() |
public void log(String message) public void log(String message, Throwable thr) | Method
log() is used to write a message to the servlet's log file. The second version writes an explanatory message and a stack trace for the specified Throwable exception to the log file.

getNamedDispatcher() |
public RequestDispatcher getNamedDispatcher(String servletName) | Method
A RequestDispatcher object sends requests from client machines to the appropriate resource (servlet, HTML file, etc.) on the server. The server creates the RequestDispatcher object which is used as a wrapper around a particular resource. getNamedDispatcher() returns a RequestDispatcher object that will be wrapped around the named servlet.

getRequestDispatcher() |
public RequestDispatcher getRequestDispatcher(String path) | Method
A RequestDispatcher object sends requests from client machines to the appropriate resource (servlet, HTML file, etc.) on the server. The server creates the RequestDispatcher object which is used as a wrapper around a particular resource. getRequestDispatcher() returns an RequestDispatcher object that acts as a wrapper around the resource located at the specified path. The path must begin with "/", and is interpreted relative to the current context root.

getResource() |
public URL getResource(String path)throws MalformedURLException | Method
getResource() returns a URL object that is mapped to the specified path. The path must begin with "/" and is interpreted relative to the current context root.

getResourceAsStream() |
public InputStream getResourceAsStream(String path) | Method
getResourceAsStream() returns the resource at the specified path as an InputStream object.

getAttribute() |
public Object getAttribute(String name) | Method
getAttribute() returns the value of the specified attribute name. The return value is an Object or sub-class if the attribute is available to the invoking ServletContext object, or null if the attribute is not available.

getAttributeNames() |
public Enumeration getAttributeNames() | Method
getAttributeNames() returns an Enumeration containing the attribute names available to the invoking ServletContext object.

removeAttribute() |
public void removeAttribute(String name) | Method
removeAttribute() makes the specified attribute unavailable to the invoking ServletContext object. Subsequent calls to the getAttribute() method for this attribute will return null.

setAttribute() |
public void setAttribute(String name, Object value) | Method
setAttribute() binds a value to a specified attribute name.

getMajorVersion() |
public int getMajorVersion() | Method
getMajorVersion() returns the major version of the Java Servlet API that the server supports. For servers supporting version 2.2 of the Servlet specification, this method will return 2.

getMinorVersion() |
public int getMinorVersion() | Method
getMinorVersion() returns the minor version of the Java Servlet API that the server supports. For servers supporting version 2.2 of the Servlet specification, this method will return 2.

getServlet() |
public Servlet getServlet(String name)throws ServletException | Deprecated
getServlet() returns the specified Servlet. This method was deprecated as of Java Servlet API 2.1 and will be permanently removed in a future version of the Servlet API.

getServletNames() |
public Enumeration getServletNames() | Deprecated
getServletNames() returns an Enumeration containing the servlet names known to the invoking ServletContext object. This method was deprecated as of Java Servlet API 2.1 and will be permanently removed in a future version of the Servlet API.

getServlets() |
public Enumeration getServlets() | Deprecated
getServlets() returns an Enumeration containing the Servlet objects known to the invoking ServletContext object. This method was deprecated as of Java Servlet API 2.1 and will be permanently removed in a future version of the Servlet API.

log() |
public void log(Exception exception, String message) | Deprecated
This version of the log() method was deprecated as of Java Servlet API 2.1. The version that takes a Throwable argument should be used in its place.