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URL Rewriting in Servlet
In URL rewriting, we append a query string to the URL. Below figure gives the different parts of a URL
Query string is a name value pair separated using an equal = sign, a name/value pair is separated from another name/value pair using the ampersand (&). Query string always should start from Question mark (?). From a Servlet, we can use getParameter(), getParameterNames() methods to obtain a name value pair.
Example for URL rewriting
Project directory structure
home.html
<!DOCTYPE html> <html> <body> <form action="../servlet1" method="post"> Enter Personal Details:<br /> Name:<input type="text" name="name" /><br /> <input type="submit" value="go" /> </form> </body> </html> |
FirstServlet.java
package com.java4coding;
import java.io.*; import javax.servlet.*; import javax.servlet.http.*;
public class FirstServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) { try { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String name = request.getParameter("name"); out.print("Welcome " + name); out.print("<form action='servlet2?name="+name+"' method='post'> "); out.print("Enter Contact Details:<br/>"); out.print("Address:<input type='text' name='address'/><br/>"); out.print("<input type='submit' value='go'/> "); out.print("</form>"); out.close(); } catch (Exception e) { System.out.println(e); } } } |
SecondServlet.java
package com.java4coding;
import java.io.*; import javax.servlet.http.*;
public class SecondServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) { try { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String address = request.getParameter("address"); String name = request.getParameter("name"); out.print("<form action='servlet3?name="+name+"&address="+address+"' method='post'> "); out.print("Enter Eduction Details:<br/>"); out.print("Education:<input type='text' name='education'/><br/>"); out.print("<input type='submit' value='go'/> "); out.print("</form>"); out.close(); } catch (Exception e) { System.out.println(e); } } } |
ThirdServlet.java
package com.java4coding;
import java.io.*;
import javax.servlet.*; import javax.servlet.http.*;
public class ThirdServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) { try { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.print("Name: " + request.getParameter("name") + "</br>"); out.print("Address: " +request.getParameter("address") + "</br>"); out.print("Education: " + request.getParameter("education")); out.close(); } catch (Exception e) { System.out.println(e); } } } |
web.xml
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:web="https://xmlns.jcp.org/xml/ns/javaee"> <servlet> <servlet-name>s1</servlet-name> <servlet-class>com.java4coding.FirstServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>s1</servlet-name> <url-pattern>/servlet1</url-pattern> </servlet-mapping> <servlet> <servlet-name>s2</servlet-name> <servlet-class>com.java4coding.SecondServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>s2</servlet-name> <url-pattern>/servlet2</url-pattern> </servlet-mapping> <servlet> <servlet-name>s3</servlet-name> <servlet-class>com.java4coding.ThirdServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>s3</servlet-name> <url-pattern>/servlet3</url-pattern> </servlet-mapping> </web-app> |
Output
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