Interface is used to handle client request to access a servlet. It provides the information of a servlet like content type, content length, parameter names and values etc.
| Methods | Description |
|---|
| public Object getAttribute(String name) | Returns the value of the named attribute as an Object. |
| public int getContentLength( ) | Returns the length of the request body in bytes. |
| public String getContentType( ) | Returns the MIME type of the request body. |
| public String getParameter(String name) | Returns the value of a request parameter as a string. |
| public String getProtocol( ) | Returns the name and version of the request protocol. |
| public int getRemotePort( ) | Returns the Internet Protocol (IP) port of the client. |
| public String getServerName( ) | Returns the host name of the server to which the request was sent. |
Example : Request to take username & password. Display username.
//index.html
<form action="test" method="post">
User Name: <input type="text" name="uname"><br>
Password: <input type = "password name = "password"><br>
<input type="submit" value="Log In">
</form>
//web.xml
<servlet>
<servlet-name>test</servlet-name>
<servlet-class>ServletDemo</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>test</servlet-name>
<url-pattern>/test</url-pattern>
</servlet-mapping>
//ServletDemo.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class ServletDemo extends HttpServlet
{
protected void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException
{
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
try
{
String username = req.getParameter("username");
String password = req.getParameter("password");
pw.println("<h1> Hello"+username+"<h1>");
}
finally
{
pw.close();
}
}
}
interface defines an object to help a Servlet in sending a response to the client. It has various methods that help a servlet to respond to the client requests.
| Methods | Description |
|---|
| public void flushBuffer( ) | It forces the content in the buffer to be written to the client. |
| public int getBufferSize( ) | Returns the actual buffer size. |
| public String getContentType( ) | Returns the content type used to send this response. |
| public PrintWriter getWriter( ) | Returns the PrintWriter object that can be used to send character text to the client. |
| public void reset( ) | Clears the buffer as well as status code and header data. |
| public void setBufferSize(int size) | Sets the specified buffer size for the body of the response. |
| public void setContentType(String type) | Sets the content type of the response being sent to the client. |
