How do I read text file in Servlet?

This example show you how to read a text file using a Servlet. Use ServletContext.getResourceAsStream() will enable you to read a file whether the web application is deployed in an exploded format or in a war file archive

package org.kodejava.example.servlet;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ReadTextFileServlet extends HttpServlet {
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {

response.setContentType("text/html");

//
// We are going to read a file called configuration.properties. This
// file is placed under the WEB-INF directory.
//
String filename = "/WEB-INF/configuration.properties";

ServletContext context = getServletContext();

//
// First get the file InputStream using ServletContext.getResourceAsStream()
// method.
//
InputStream is = context.getResourceAsStream(filename);
if (is != null) {
InputStreamReader isr = new InputStreamReader(is);
BufferedReader reader = new BufferedReader(isr);
PrintWriter writer = response.getWriter();
String text = "";

//
// We read the file line by line and later will be displayed on the
// browser page.
//
while ((text = reader.readLine()) != null) {
writer.println(text);
}
}
}

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

The configuration.properties file is just a regular text file. Below is an example of the configuration we are going to read.

app.appname=Servlet Examples
app.version=1.0
app.copyright=2007