Spring application context example - using Spring in a standalone Java application

Spring application context FAQ: Can you provide an example of using a Spring application context file in a standalone Java application?

Sure. Here's an example of a simple Java program where I load a Spring application context file using the ClassPathXmlApplicationContext method. This is a typical way of loading the application context file in a Spring standalone application, i.e., something like a Swing application or some other standalone Java application (some form of client or server) started from a Java jar file.

In the example program shown below I load the Spring application context file (applicationContext.xml) almost immediately after the main method is started, and then I instantiate (create) a couple of Java beans whose definitions are stored in the Spring application context file.

The example Spring standalone application

Here's a simple example Java standalone program that loads my Spring application context file and creates a few beans from the application context file:

package com.devdaily.springtest1;

import com.devdaily.springtest1.dao.FileEventDao;
import com.devdaily.springtest1.bean.FileEventType;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class SpringApplicationContextExample

  public static void main (String[] args)
    new Main();

  public SpringApplicationContextExample()
    // open/read the application context file
    ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");

    // instantiate our spring dao object from the application context
    FileEventDao fileEventDao = (FileEventDao)ctx.getBean("fileEventDao");

    // create a FileEventType object from the application context
    FileEventType fileEventType = (FileEventType)ctx.getBean("fileEventType");

    // insert the file event with the spring dao


The Spring application context file

This Java source code won't make a great deal of sense without also seeing the contents of the application context file that goes with this program, so here's the source code for the corresponding Spring applicationContext.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">


  <bean id="fileEventType" class="com.devdaily.springtest1.bean.FileEventType">
    <property name="eventType" value="10"/>
    <property name="description" value="A sample description here"/>

  <bean id="fileEventDao" class="com.devdaily.springtest1.dao.FileEventDao">
    <property name="dataSource" ref="basicDataSource"/>

  <bean id="basicDataSource" class="org.apache.commons.dbcp.BasicDataSource">
    <property name="driverClassName" value="com.mysql.jdbc.Driver" />
    <property name="url" value="jdbc:mysql://localhost/my_database" />
    <property name="username" value="my_username" />
    <property name="password" value="my_password" />
    <property name="initialSize" value="3" />
    <property name="maxActive" value="10" />


How the Spring application context file is loaded

Because I'm using the Spring ClassPathXmlApplicationContext method to load my applicationContext.xml file in this example application, all I have to do for this to work is make sure the applicationContext.xml file is in my classpath when I run my Java application. If your CLASSPATH includes your current directory there's really nothing you have to do.

(For a web application this is as simple as making sure this file ends up in the WEB-INF/classes folder, BUT, for web applications you don't really want to take this approach to loading your application context file. I'll discuss that approach in another tutorial.)

One other thing I should note is that some of this Spring application context file refers to a MySQL database setup, and requires the Apache Commons connection pooling library. If you're interested in seeing how this sample program works but you're not interested in connecting to a database, just remove all those lines and try to load your own beans from your own definitions.



Great article. Thank you.


Really useful, concise and just with the details that really matter (I.e. Pooling)