Running a local http server for dumping output to webpage

Running a local http server for dumping output to webpage.

At our project for encryption ,we had the constraint that we will not be
putting descrypted or open data to network.
There is a client program (Swing) running encrypt decrypt jobs.
Encrypted files are stored at server.

Also users will be able to download encrypted files into their local from a web page.
How could we do that?

1)We generated links like :
http://127.0.0.1:58997/download/-1584127920xe48f773bd522664b1f94d7c926e144bb

2)We opened an Httpserver listening the port specified.

3)User was seeing link in web page.But link was triggering our client program.

4)Program was downloading file parts from server,decrypting them
and writing to response of http request.

Below is piece of codes for this logic.It is not complete but enough.

import java.io.IOException ;
import java.net.InetSocketAddress ;
import java.util.HashMap ;
import java.util.Map ;

import com.sun.net.httpserver.HttpHandler ;
import com.sun.net.httpserver.HttpServer ;

public class KEmbeddedHttpServer 
{
    protected HttpServer server ;

    protected int port ;

    protected Map handlerMap = new HashMap<>( ) ;

    public KEmbeddedHttpServer( int port )
    {
        this.port = port ;
    }

    public HttpServer getServer( )
    {
        return this.server ;
    }

    public int getPort( )
    {
        return this.port ;
    }

    public void setPort( int port )
    {
        this.port = port ;
    }

    public void addHandler( String context, HttpHandler handler )
    {
        this.handlerMap.put( context, handler ) ;
    }

    public void start( ) throws IOException
    {
        this.server = HttpServer.create( new InetSocketAddress( this.port ), 0 ) ;

        for( String context : this.handlerMap.keySet( ) )
        {
            this.server.createContext( "/" + context, this.handlerMap.get( context ) ) ;
        }

        this.server.setExecutor( null ) ; // creates a default executor

        this.server.start( ) ;
    }
}



public void doHandleRequest( final HttpExchange httpExchange ) throws IOException
    {
        String requestPath = httpExchange.getRequestURI( ).getPath( ) ;
        
            try
            {
                

                final String fileName = decFileMeta.substring( 0, decFileMeta.indexOf( ", @" ) ).trim( ) ;

                final OutputStream os = httpExchange.getResponseBody( ) ;

                IKObserver observer = new IKObserver( )
                {
                    @Override
                    public Boolean onAction( String action, byte[ ] data )
                    {
                        try
                        {
                            if( BLOCK_READ.equals( action ) )
                            {
                                os.write( data ) ;
                            }
                            else if( START_OF_OPERATION.equals( action ) )
                            {
                                httpExchange.getResponseHeaders( ).add( "Content-Disposition", "attachment; filename=" + fileName ) ;
                                httpExchange.getResponseHeaders( ).add( "Transfer-encoding", "chunked" ) ;
                                httpExchange.sendResponseHeaders( 200, 0 ) ;
                            }
                            else if( END_OF_OPERATION.equals( action ) )
                            {
                                if( os != null )
                                {
                                    os.flush( ) ;
                                    os.close( ) ;
                                }
                            }

                            return Boolean.TRUE ;
                        }
                        catch( Exception ex )
                        {
                            ex.printStackTrace( ) ;
                            return false ;
                        }
                    }
                } ;


                
            }
            catch( Exception e )
            {
                e.printStackTrace( ) ;
                e.printStackTrace( new PrintWriter( this.writer ) ) ;
                httpExchange.getResponseHeaders( ).add( "Content-Disposition", "inline; filename=error.html" ) ;
                httpExchange.sendResponseHeaders( 500, this.baos.size( ) ) ;
            }

        

    }