PropertyPlaceholderConfigurer

A property resource configurer that resolves placeholders in bean property values of context definitions. It pulls values from a properties file into bean definitions.

Example :

 

 pom.xml

<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.mahesh.core</groupId>
 <artifactId>springexample</artifactId>
 <version>0.0.1-SNAPSHOT</version>
        <name>SpringExample</name>
 <dependencies>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-core</artifactId>
   <version>${spring.version}</version>
  </dependency>
  <dependency>
   <groupId>org.springframework</groupId>
   <artifactId>spring-context</artifactId>
   <version>${spring.version}</version>
  </dependency>
 </dependencies>

 <properties>
  <spring.version>3.1.2.RELEASE</spring.version>
 </properties>
</project>

Create a simple Spring Bean with Properties

package com.mahesh.spring;

public class PropertyRead {

    private String url;
    private String driverName;
    private String password;
    public String getUrl() {
        return url;
    }
    public void setUrl(String url) {
        this.url = url;
    }
    public String getDriverName() {
        return driverName;
    }
    public void setDriverName(String driverName) {
        this.driverName= driverName;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }   

}

ResourcesBundle.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/sample
jdbc.username=root
jdbc.password=root

Define the PropertyPlaceholderConfigurer

<beans xmlns="http://www.springframework.org/schema/beans"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://www.springframework.org/schema/beans
 http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
 
 <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
 
  <property name="location">
   <value>ResourceBundle.properties</value>
  </property>
 </bean>

 
 <bean id="reader"
  class="com.mahesh.spring.PropertyRead">
 
  <property name="url" value="${jdbc.url}" />
  <property name="username" value="${jdbc.username}" />
  <property name="password" value="${jdbc.password}" />
 </bean>
 
</beans>

Run Application

package com.mahesh.spring;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.mahesh.spring.PropertyRead;

public class App {
 
 public static void main(String[] args) {
 
   ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
   
   PropertyRead read = (PropertyRead) context.getBean("reader");
   
   read.getUrl();
   
   read.getPassword();
 }
}