Often times, most Spring developers just put the entire deployment details (database details, log file path) in XML bean configuration file as following :
<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 id="customerDAO" class="com.mkyong.customer.dao.impl.JdbcCustomerDAO">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="customerSimpleDAO" class="com.mkyong.customer.dao.impl.SimpleJdbcCustomerDAO">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/mkyongjava" />
<property name="username" value="root" />
<property name="password" value="password" />
</bean>
</beans>
But, in a corporate environment, deployment detail is usually only can ‘touch’ by your system or database administrator, they just refuse to access your bean configuration file directly, and they will request a separate file for deployment configuration, for example, a simple properties, with deployment detail only.
PropertyPlaceholderConfigurer example
To fix it, you can use PropertyPlaceholderConfigurer class to externalize the deployment details into a properties file, and access from bean configuration file via a special format – ${variable}.
Create a properties file (database.properties), include your database details, put it into your project class path.
jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mkyongjava
jdbc.username=root
jdbc.password=password
Declare a PropertyPlaceholderConfigurer in bean configuration file and map to the ‘database.properties‘ properties file you created just now.
<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location">
<value>database.properties</value>
</property>
</bean>
Full example
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location">
<value>database.properties</value>
</property>
</bean>
<bean id="customerDAO" class="com.mkyong.customer.dao.impl.JdbcCustomerDAO">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="customerSimpleDAO"
class="com.mkyong.customer.dao.impl.SimpleJdbcCustomerDAO">
<property name="dataSource" ref="dataSource" />
</bean>
<bean id="dataSource"
class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${jdbc.driverClassName}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</bean>
</beans>
You also can use PropertyPlaceholderConfigurer to share some constant variables to all other beans. For example, define your log file location in a properties file, and access the properties value from different beans configuration files via
${log.filepath}.
Thank you..
Hello mkyong how are you?
I have a question: in this moment, I want to obtain a property that is found in file project-properties.prorperties, according to the environment to use
myProject
->module1
—->api
—->core
—->projectweb
—–pom.xml
->module2
—->api
—->core
—->projectWeb
—–pom.xml
->module3
—->api
—->core
—->projectWeb
—–pom.xml
->properties
—->environmentdevelopment
——-project-properties.properties
—->environmentlocal
——-project-properties.properties
pom.xml
do we need to use beans xml if we are using spring boot?
When do we use #{…} instead if ${…} and how both are different. Also please explain what does it mean – #{${..}}
Where is the applicability of the location variable? I only see the define point of it.
How to include property file in groovy.config file
Thats really useful!! Many Many Thanks!!!!! 😀
Hi,
I have a base project that contains base services(written in spring). I have also a spring mvc project that has a maven dependency to base spring project. Base spring project has property files and the other spring mvc project has property files too. But if i didn’t redefine base project’s property files in spring mvc project it throws error. So i redefine the base projects property files also in spring mvc project. Is there a way to define property files only in its project?
Hi,
This example states how to get the values inside the configuration file. Using PropertyPlaceholderConfigurer, How to get the property values inside a java class.
Hello, you can use Environment. Here is the example:
@PropertySource(“some property file”)
class A{
@Autowired
Environment env;
public void setProperties{
String property = env.getgetProperty(“Property name”);
}
}
If i chose to place the property file external to the application (EAR/WAR), and when the property file changes, would restart the application get the new property to be in effect ?
I am trying to supply a runtime name of the file (my message queue.properties file differs for my different environment)
But I am not able to set the $hostname} with the name of my hostname for spring application context to load it dynamically.
If you have pointers for the same that would be really helpful
You forgot to say where to deploy the properties file! Your post is pretty close to useless..
just great!!. thanks
how to read properties file using spring…
Is there any way to init a Bean’s property of Map type using properties file?I have searched for it for a whole day?but I found none. Thx a lot. Looking forward to your reply.
Why not u can put the values in Property file like below
key1=Value1
key2=Value2
key3=Value3
And then assign this in the Spring configured XML like
<bean id = "someClass" class="somePackage.SomeClass"> <property name=""someMap> <map> <entry key="key1" value="${key1}" /> <entry key="key1" value="${key1}" /> <entry key="key1" value="${key1}" /> </map> </property> </bean>Thanks a lot for the crisp and useful article
can we have PropertyPlaceholderConfigurer read properties file from the file system?
Yes, using file:relativepath or file:absolutepath both pointing to your properties file in the filesystem.
Thanks again ))
Got just what I wanted in seconds
This example was really helpful, thanks a lot for the post. This gave me just what I needed.