Sunday, October 17, 2010

Injecting file dependency into Spring bean

Continuing to explore power of Spring Framework, I would like to explain how to inject file resource into the Spring bean using @Resource annotation.

First of all, let's start with beans definition file. We need basically to declare file dependency we would like to inject:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns=""

   <context:annotation-config />   
   <context:component-scan base-package="org.example" />

   <bean id="source" class="">
      <constructor-arg index="0" value="some.file.txt" />


Having configuration part is ready, we can inject file to a bean.
package org.example;

import java.util.List;

import javax.annotation.Resource;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

public class SomeBean implements InitializingBean {   
 @Autowired @Resource( name = "source" ) private InputStreamSource source; 
 public SomeBean () {
 public void afterPropertiesSet() throws Exception {
     for( final String line: ( List< String > )IOUtils.readLines( source.getInputStream() ) ) {
                // do something here    
That's it :)
Pretty easy and powerful technique.

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