Read property file Of WEBINF folder In servlet context example

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This is input.html JSP file and it is used display the output for the application.




<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

<html>

<head>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

<title>Context Param</title>

</head>

<body>

<form  method="POST" action="ContextParamServlet">  

    <br><br>

    <center>

        <input type="SUBMIT" value="Please Click here">

    </center>  

</form>

</body>

</html>






This is app.properties properties file and these properties are used in the application.



proeprty1 = value1

proeprty2 = value2

proeprty3 = value3






This is ContextParamServlet.java file having the source code to execute business logic.





  
  








 

    
package com.cv.servlet.context.listeners;



import java.io.IOException;

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;



import org.apache.log4j.Logger;



/**

 * @author Chandra Vardhan

 *

 */

public class ContextParamServlet extends HttpServlet {



  private static final Logger LOGGER = Logger.getLogger(ContextParamServlet.class);



  public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

    LOGGER.info("Entered into doGet(--) of ContextParamServlet class... ");

    response.setContentType("text/plain");

    PrintWriter printWriter = response.getWriter();

    ServletContext context = getServletContext();

    String realPath = context.getRealPath("/app.properties");

    LOGGER.info("Getting realPath : : " + realPath);

    printWriter.print("Getting realPath : : " + realPath+"\n");    

    printWriter.print("\nPlease look at the start up logs...");

  }



  /**

   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse

   *      response)

   */

  protected void doPost(HttpServletRequest request, HttpServletResponse response)

      throws ServletException, IOException {

    LOGGER.info("Entered into doPost(--) of ContextParamServlet class... ");

    doGet(request, response);

  }



}

    














This is ServletContextListenerImpl.java file having the source code to execute business logic.





  
  








 

    
package com.cv.servlet.context.listeners;



import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.util.Properties;



import javax.servlet.ServletContext;

import javax.servlet.ServletContextEvent;

import javax.servlet.ServletContextListener;



import org.apache.log4j.Logger;



/**

 * @author Chandra Vardhan

 *

 */

public class ServletContextListenerImpl implements ServletContextListener {



  private static final Logger LOGGER = Logger.getLogger(ServletContextListenerImpl.class);

  

  @Override

  public void contextDestroyed(ServletContextEvent event) {



    LOGGER.info("ServletContextListenerImpl... ServletContextEvent... contextDestroyed...");

  }



  @Override

  public void contextInitialized(ServletContextEvent event) {

    LOGGER.info("ServletContextListenerImpl class of contextInitialized(ServletContextEvent)...");

    ServletContext servletContext = event.getServletContext();

    String contextPath = servletContext.getContextPath();

    String realPath = servletContext.getRealPath("/app.properties");

    String result = "";

    int lastIndexOf = realPath.lastIndexOf("\\");

    String firstStr = realPath.substring(0, lastIndexOf);

    String lastStr = realPath.substring(lastIndexOf, realPath.length());

    result = firstStr + "\\WEB-INF" + lastStr;

    Properties props = new Properties();

    try {

      props.load(new FileInputStream(result));

    } catch (FileNotFoundException e) {

      e.printStackTrace();

    } catch (IOException e) {

      e.printStackTrace();

    }

    

    LOGGER.info("Value of contextPath is : " + contextPath + " set as contextPath...");

    LOGGER.info("Value of realPath is : " + result + " set as realPath...");

    LOGGER.info("Value of properties is : " + props);

  }

}

    










This is pom.xml file having the entries of dependency jars and information to build the application .


	
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.cv.servlet.context.listeners</groupId>
  <artifactId>ReadPropertyFileOfWEBINFFolderInServletContext</artifactId>
  <version>1.0</version>
  <packaging>war</packaging>
 <properties>
		<log4j-version>1.2.16</log4j-version>
		<java.version>1.8</java.version>
	</properties>

	<build>
		<plugins>
			<plugin>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.3</version>
				<configuration>
					<source>${java.version}</source>
					<target>${java.version}</target>
				</configuration>
			</plugin>
			<plugin>
				<artifactId>maven-war-plugin</artifactId>
				<version>2.6</version>
				<configuration>
					<warSourceDirectory>src/main/webapp</warSourceDirectory>
					<failOnMissingWebXml>false</failOnMissingWebXml>
				</configuration>
			</plugin>
		</plugins>
	</build>
	<dependencies>
		<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>servlet-api</artifactId>
			<version>3.0-alpha-1</version>
		</dependency>
		<dependency>
			<groupId>commons-fileupload</groupId>
			<artifactId>commons-fileupload</artifactId>
			<version>1.3.1</version>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>${log4j.version}</version>
		</dependency>

	</dependencies>
</project>




This is web.xml deployment descriptor file and it describes how the web application should be deployed.


	
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" version="3.1">
  <display-name>ReadPropertyFileOfWEBINFFolderInServletContext</display-name>
  <context-param>
    <param-name>contextParam</param-name>
    <param-value>JokeyIsTheFirstPetName</param-value>
  </context-param>
  <servlet>
    <servlet-name>ContextParamServlet</servlet-name>
    <servlet-class>com.cv.servlet.context.listeners.ContextParamServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>ContextParamServlet</servlet-name>
    <url-pattern>/ContextParamServlet</url-pattern>
  </servlet-mapping>
  <listener>
    <listener-class>com.cv.servlet.context.listeners.ServletContextListenerImpl</listener-class>
  </listener>
  <welcome-file-list>
    <welcome-file>input.html</welcome-file>
  </welcome-file-list>
</web-app>






This is log4j.properties file having the entries for logging the information into the console/file. 



#By default enabling Console appender
# Root logger option
log4j.rootLogger=INFO, stdout

# Redirect log messages to console
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%-5p [%c]:%L -->> %m%n

# Redirect log messages to a log file
#log4j.appender.file=org.apache.log4j.RollingFileAppender
#log4j.appender.file.File=C:\servlet-application.log
#log4j.appender.file.MaxFileSize=5MB
#log4j.appender.file.MaxBackupIndex=10
#log4j.appender.file.layout=org.apache.log4j.PatternLayout
#log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n










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