(JAVA Servlets using tomcat) Using a form for text input (name = \'query\') and

Question

(JAVA Servlets using tomcat) Using a form for text input (name = 'query') and submit, modify the GuestBook servlet so that it has a "search" function. For example, typing a word or letter and clicking the submit button would return any result with that word/letter in the Name or Message column as a table. The following is the code that is to be added onto, which works as an ordinary guestbook, all that needs to be done is a modification of Guestbook.java:
Guestbook.java
package cs320.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cs320.model.GuestBookEntry;

@WebServlet(urlPatterns = "/GuestBook", loadOnStartup = 2)
public class GuestBook extends HttpServlet {

    private static final long serialVersionUID = 1L;

    public GuestBook()
    {
        super();
    }

    public void init( ServletConfig config ) throws ServletException
    {
        super.init( config );

        // create some test data for display
        List entries = new ArrayList();
        entries.add( new GuestBookEntry( 1, "john", "hello" ) );
        entries.add( new GuestBookEntry( 2, "joe", "hi" ) );

        // stored the data somewhere that can be accessed by this servlet
        // and other servlets.
        getServletContext().setAttribute( "entries", entries );
    }

    @SuppressWarnings("unchecked")
    protected void doGet( HttpServletRequest request,
        HttpServletResponse response ) throws ServletException, IOException
    {
        // get the data
        List entries = (List) getServletContext().getAttribute(
            "entries" );

        // display it
        response.setContentType( "text/html" );
        PrintWriter out = response.getWriter();
        out.println( "

Guest Book

" );

        out.println( "" );
        out.println( "" );
        for( GuestBookEntry entry : entries )
        {
            out.println( "" );
        }
        out.println( "

" );

        out.println( "

Add Comment

" );

        out.println( "" );
    }

    protected void doPost( HttpServletRequest request,
        HttpServletResponse response ) throws ServletException, IOException
    {
        doGet( request, response );
    }

}

GuestBookEntry.java

AddComment.java

Add Comment" ); out.println( "

" ); out.println( "Name:
" ); out.println( "
" ); out.println( "
" ); out.println( "

" ); out.println( "" ); } @SuppressWarnings("unchecked") protected void doPost( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException { // get the user input String name = request.getParameter( "name" ); String message = request.getParameter( "message" ); // create a new guest book entry GuestBookEntry entry = new GuestBookEntry( idSeed++, name, message ); // add the new entry to the guest book List entries = (List) getServletContext().getAttribute( "entries" ); entries.add( entry ); // send the user back to the guest book page response.sendRedirect( "GuestBook" ); } }

EditComment.java

package cs320.servlet; import java.io.IOException; import java.io.PrintWriter; import java.util.List; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import cs320.model.GuestBookEntry; @WebServlet("/EditComment") public class EditComment extends HttpServlet { private static final long serialVersionUID = 1L; public EditComment() { super(); } /** * Given an id, retrieve the GuestBookEntry. */ @SuppressWarnings("unchecked") private GuestBookEntry getEntry( Integer id ) { List entries = (List) getServletContext().getAttribute( "entries" ); for( GuestBookEntry entry : entries ) if( entry.getId().equals( id ) ) return entry; return null; } protected void doGet( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException { // get the entry to be edited Integer id = Integer.valueOf( request.getParameter( "id" ) ); GuestBookEntry entry = getEntry( id ); // form display response.setContentType( "text/html" ); PrintWriter out = response.getWriter(); out.println( "Edit Comment" ); out.println( "

" ); out.println( "Name: " ); out.println( "" + entry.getMessage() + " " ); // hidden form field out.println( " " ); out.println( " " ); out.println( "

" ); out.println( "" ); } protected void doPost( HttpServletRequest request, HttpServletResponse response ) throws ServletException, IOException { // get the entry to be edited Integer id = Integer.valueOf( request.getParameter( "id" ) ); GuestBookEntry entry = getEntry( id ); // change the entry based on user input entry.setName( request.getParameter( "name" ) ); entry.setMessage( request.getParameter( "message" ) ); // send the user back to the guest book page response.sendRedirect( "GuestBook" ); } }

DeleteComment.java

Id Name Message " + entry.getId() + " "
                + entry.getName() + " " + entry.getMessage()
                + " Edit Delete

Explanation / Answer

// Added code for doing search, please check the comments:

// User can get the search query using String query = request.getParameter("query");

// Based on search query we can do filtering, if search query is available in name or message, return all records if search query is empty.

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