Java Tutorial/Servlet/XML Word PDF Mp3

Display PDF based on Request Parameter

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.net.*;
public class MyServlet extends HttpServlet {
   
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
      String fileName = (String) request.getParameter("file");
      if (fileName == null || fileName.equals(""))
           throw new ServletException(
            "Invalid or non-existent file parameter in UrlServlet servlet.");
      
      if (fileName.indexOf(".pdf") == -1)
          fileName = fileName + ".pdf";
        
      URL pdfDir = null;
      URLConnection urlConn = null;
      ServletOutputStream stream = null;
      BufferedInputStream buf = null;
     try{
     
       pdfDir = new URL(getServletContext().getInitParameter("remote-pdf-dir") + fileName);
    
    } catch (MalformedURLException mue){
    
           throw new ServletException(mue.getMessage());
   }
   try{
          
     stream = response.getOutputStream();
      response.setContentType("application/pdf");
      response.addHeader(
        "Content-Disposition","attachment; filename="+fileName );
      
      urlConn = pdfDir.openConnection();
      response.setContentLength( (int) urlConn.getContentLength()  );
     
     buf = new BufferedInputStream(urlConn.getInputStream());
     int readBytes = 0;
     while((readBytes = buf.read()) != -1)
        stream.write(readBytes);
     } catch (IOException ioe){
     
        throw new ServletException(ioe.getMessage());
         
     } finally {
     
     if(stream != null)
         stream.close();
      if(buf != null)
          buf.close();
          }
    
    }
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        
        doGet(request,response);
    } 
}

Send MP3 file back to client with Servlet

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.text.DateFormat;
public class MyServlet extends HttpServlet {
   
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      String fileName = (String) request.getParameter("file");
      if (fileName == null || fileName.equals(""))
           throw new ServletException(
            "Invalid or non-existent file parameter in SendMp3 servlet.");
      
      if (fileName.indexOf(".mp3") == -1)
          fileName = fileName + ".mp3";
          
     String mp3Dir = getServletContext().getInitParameter("mp3-dir");
     if (mp3Dir == null || mp3Dir.equals(""))
           throw new ServletException(
             "Invalid or non-existent mp3Dir context-param.");
          
      ServletOutputStream stream = null;
      BufferedInputStream buf = null;
      try{
     
      stream = response.getOutputStream();
      File mp3 = new File(mp3Dir + "/" + fileName);
     
      response.setContentType("audio/mpeg");
      
      response.addHeader("Content-Disposition","attachment; filename="+fileName );
      response.setContentLength( (int) mp3.length() );
      
      FileInputStream input = new FileInputStream(mp3);
      buf = new BufferedInputStream(input);
      int readBytes = 0;
      while((readBytes = buf.read()) != -1)
         stream.write(readBytes);
     } catch (IOException ioe){
     
        throw new ServletException(ioe.getMessage());
         
     } finally {
     if(stream != null)
         stream.close();
      if(buf != null)
          buf.close();
          }
    
    } //end doGet
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        
        doGet(request,response);
    } 
}

Send Pdf to client using Servlet

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.text.DateFormat;
public class MyServlet extends HttpServlet {
   
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
      String fileName = (String) request.getParameter("file");
      if (fileName == null || fileName.equals(""))
           throw new ServletException(
            "Invalid or non-existent file parameter in SendPdf servlet.");
      
      if (fileName.indexOf(".pdf") == -1)
          fileName = fileName + ".pdf";
          
     String pdfDir = getServletContext().getInitParameter("pdf-dir");
     if (pdfDir == null || pdfDir.equals(""))
           throw new ServletException(
             "Invalid or non-existent "pdf-Dir" context-param.");
          
      ServletOutputStream stream = null;
      BufferedInputStream buf = null;
     try{
     
     stream = response.getOutputStream();
     File pdf = new File(pdfDir + "/" + fileName);
     
      response.setContentType("application/pdf");
      
      response.addHeader(
        "Content-Disposition","attachment; filename="+fileName );
      response.setContentLength( (int) pdf.length() );
      
     FileInputStream input = new FileInputStream(pdf);
     buf = new BufferedInputStream(input);
     int readBytes = 0;
     while((readBytes = buf.read()) != -1)
        stream.write(readBytes);
     } catch (IOException ioe){
     
        throw new ServletException(ioe.getMessage());
         
     } finally {
   
   if(stream != null)
       stream.close();
    if(buf != null)
          buf.close();
      }
    
    }
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
  
  doGet(request,response);
  
    } 
}

Send Word file to client in a Servlet

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.text.DateFormat;
public class MyServlet extends HttpServlet {
   
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      String fileName = (String) request.getParameter("file");
      if (fileName == null || fileName.equals(""))
           throw new ServletException(
            "Invalid or non-existent file parameter in SendWord servlet.");
      
      if (fileName.indexOf(".doc") == -1)
          fileName = fileName + ".doc";
          
     String wordDir = getServletContext().getInitParameter("word-dir");
     if (wordDir == null || wordDir.equals(""))
           throw new ServletException(
             "Invalid or non-existent wordDir context-param.");
          
      ServletOutputStream stream = null;
      BufferedInputStream buf = null;
     try{
     
     stream = response.getOutputStream();
     File doc = new File(wordDir + "/" + fileName);
     
      //set response headers
      response.setContentType("application/msword");
      
      response.addHeader(
        "Content-Disposition","attachment; filename="+fileName );
      response.setContentLength( (int) doc.length() );
      
     FileInputStream input = new FileInputStream(doc);
     buf = new BufferedInputStream(input);
     int readBytes = 0;
     while((readBytes = buf.read()) != -1)
        stream.write(readBytes);
     } catch (IOException ioe){
     
        throw new ServletException(ioe.getMessage());
         
     } finally {
     
     if(stream != null)
         stream.close();
      if(buf != null)
          buf.close();
          }
    
    }
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        
        doGet(request,response);
    } 
}

Send XML data to client

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.net.*;
public class MyServlet extends HttpServlet {
   
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
      String file = "/WEB-INF/web.xml";
     
      URL url = null;
      URLConnection urlConn = null;  
      PrintWriter out = null;
      BufferedInputStream buf = null;
     try{
     out = response.getWriter();
     url = getServletContext().getResource(file);
      response.setContentType("text/xml");
    
      urlConn = url.openConnection();
     urlConn.connect();
     buf = new BufferedInputStream(urlConn.getInputStream());
     int readBytes = 0;
     //read from the file; write to the PrintWriter
     while((readBytes = buf.read()) != -1)
        out.write(readBytes);
     } catch (MalformedURLException mue){
    
           throw new ServletException(mue.getMessage());
           
     } catch (IOException ioe){
     
        throw new ServletException(ioe.getMessage());
         
     } finally {
     
     if(out != null)
         out.close();
      if(buf != null)
          buf.close();
          }
    
    } //end doGet
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        
        doGet(request,response);
    } 
}

Send XML to client using Servlet

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.text.DateFormat;
public class MyServlet extends HttpServlet {
   
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
      String fileName = (String) request.getParameter("file");
      if (fileName == null || fileName.equals(""))
           throw new ServletException(
            "Invalid or non-existent file parameter in SendXml servlet.");
      
      if (fileName.indexOf(".xml") == -1)
          fileName = fileName + ".xml";
          
     String xmlDir = getServletContext().getInitParameter("xml-dir");
     if (xmlDir == null || xmlDir.equals(""))
           throw new ServletException(
             "Invalid or non-existent xmlDir context-param.");
          
      ServletOutputStream stream = null;
      BufferedInputStream buf = null;
     try{
     
     stream = response.getOutputStream();
     File xml = new File(xmlDir + "/" + fileName);
     
      response.setContentType("text/xml");
      
      response.addHeader(
        "Content-Disposition","attachment; filename="+fileName );
      response.setContentLength( (int) xml.length() );
      
     FileInputStream input = new FileInputStream(xml);
     buf = new BufferedInputStream(input);
     int readBytes = 0;
     //read from the file; write to the ServletOutputStream
     while((readBytes = buf.read()) != -1)
        stream.write(readBytes);
     } catch (IOException ioe){
     
        throw new ServletException(ioe.getMessage());
         
     } finally {
     
     if(stream != null)
         stream.close();
      if(buf != null)
          buf.close();
          }
    
    }
   
    public void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        
        doGet(request,response);
    } 
}

Use XPath in servlet

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.jdom.Document;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.jdom.xpath.XPath;
public class PostServlet extends HttpServlet {
    private SAXBuilder builder = new SAXBuilder();
    private XPath nameXPath;
    private XPath yearXPath;
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        if (!"text/xml".equals(request.getContentType())) {
            response.getWriter().println("Please post as text/xml.");
        } else {
            try {
                Document doc = builder.build(request.getReader());
                StringBuffer buff = new StringBuffer();
                buff.append("You searched for name "" + nameXPath.valueOf(doc)
                        + """);
                String year = yearXPath.valueOf(doc);
                if (!"notselected".equals(year)) {
                    buff.append(" and year "" + year + """);
                }
                buff.append(".");
                response.getWriter().print(buff.toString());
            } catch (JDOMException e) {
                response.getWriter().print(
                        "Error getting search terms: " + e.getMessage());
            }
        }
    }
    public void init() throws ServletException {
        try {
            nameXPath = XPath.newInstance("/search/name/text()");
            yearXPath = XPath.newInstance("/search/year/text()");
        } catch (JDOMException e) {
            throw new ServletException("Unable to create XPaths", e);
        }
        super.init();
    }
}