307

I have a bunch of Spring beans which are picked up from the classpath via annotations, e.g.

@Repository("personDao")
public class PersonDaoImpl extends AbstractDaoImpl implements PersonDao {
    // Implementation omitted
}

In the Spring XML file, there's a PropertyPlaceholderConfigurer defined:

<bean id="propertyConfigurer" 
  class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="/WEB-INF/app.properties" />
</bean> 

I want to inject one of the properties from app.properites into the bean shown above. I can't simply do something like

<bean class="com.example.PersonDaoImpl">
    <property name="maxResults" value="${results.max}"/>
</bean>

Because PersonDaoImpl does not feature in the Spring XML file (it is picked up from the classpath via annotations). I've got as far as the following:

@Repository("personDao")
public class PersonDaoImpl extends AbstractDaoImpl implements PersonDao {

    @Resource(name = "propertyConfigurer")
    protected void setProperties(PropertyPlaceholderConfigurer ppc) {
    // Now how do I access results.max? 
    }
}

But it's not clear to me how I access the property I'm interested in from ppc?

Peter Mularien
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Dónal
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    I've asked essentially the same question, although in a slightly different scenario: http://stackoverflow.com/questions/310271/injecting-beans-into-a-class-outside-the-spring-managed-context. So far, no one has been able to answer it. – Spencer Kormos Nov 25 '08 at 17:05
  • Please note that as of Spring 3.1, `PropertyPlaceholderConfigurer` is no longer the recommended class. Prefer `PropertySourcesPlaceholderConfigurer` instead. In any case, you can use the shorter XML definition ``. – Michael Piefel Oct 30 '13 at 14:09
  • http://stackoverflow.com/questions/28756014/how-to-configure-dynamic-properties-while-using-spring-boot – kervin Jul 30 '16 at 04:35

19 Answers19

306

You can do this in Spring 3 using EL support. Example:

@Value("#{systemProperties.databaseName}")
public void setDatabaseName(String dbName) { ... }

@Value("#{strategyBean.databaseKeyGenerator}")
public void setKeyGenerator(KeyGenerator kg) { ... }

systemProperties is an implicit object and strategyBean is a bean name.

One more example, which works when you want to grab a property from a Properties object. It also shows that you can apply @Value to fields:

@Value("#{myProperties['github.oauth.clientId']}")
private String githubOauthClientId;

Here is a blog post I wrote about this for a little more info.

Blue
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    Is `systemProperties` simply `System.getProperties()`? I guess if I want to inject my own properties into a Spring bean I need to define a `` then read values from that into another bean using something like `@Value("#{appProperties.databaseName}")` – Dónal Apr 06 '11 at 20:50
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    Make sure to note from max's answer that you can also use placeholders in the expressions ${db.doStuff}, then you don't need a PropertiesFactoryBean, just a placeholderConfigurer – gtrak Jul 21 '11 at 00:15
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    You can add your own properties using util:properties; e.g., . See the edited answer for how to get the value. (I realize this is probably too late to have been helpful to Don, but others will hopefully benefit.) –  Jan 28 '12 at 19:34
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    It only worked for me when I used util:properties in my appname-servlet.xml file. Using propertyConfigurer defined in my applicationContext.xml (not the Spring MVC one) didn't work. – Asaf Mesika Oct 07 '12 at 10:15
  • For a little further reading, that elaborates on some of this, check out this SOF question too: http://stackoverflow.com/questions/6425795/injecting-properties-using-spring-annotation-value/6430610#6430610 – arcseldon Aug 21 '13 at 04:53
  • Anyway to add the import statements on a java example? #recurringTheme – granadaCoder Feb 18 '20 at 18:02
152

Personally I love this new way in Spring 3.0 from the docs:

private @Value("${propertyName}") String propertyField;

No getters or setters!

With the properties being loaded via the config:

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer"
      p:location="classpath:propertyFile.properties" name="propertiesBean"/>

To further my glee I can even control click on the EL expression in IntelliJ and it brings me to the property definition!

There's also the totally non xml version:

@PropertySource("classpath:propertyFile.properties")
public class AppConfig {

    @Bean
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }
Alex Weitz
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barrymac
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    make sure and add in the namespace uri xmlns:p="http://www.springframework.org/schema/p" to use the p: prefixed attributes. – shane lee Oct 31 '12 at 09:55
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    Why this methods works in a test context but not in the main context ? – luksmir Sep 05 '13 at 08:03
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    sigh, I spent hour trying to make annotations-only approach work and discovered what is missing only after reading this answer- declaration of a magical static bean PropertySauceYadaYada. Spring love! – Kranach Mar 03 '15 at 22:12
  • @barrymac hey barry, do U know what is the difference between @Value(#{...}) and @Value(${...}). Thank you – Kim Mar 23 '17 at 08:20
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    This works for me. Only one tip: annotation @Component is required. – yaki_nuka Apr 26 '17 at 16:40
  • How does Spring instantiate that private field under the hood if it doesn't have a setter? – ROMANIA_engineer Jul 09 '18 at 14:34
  • It works with application.properties but I couldn't make it working with application.yaml – Enrico Giurin Mar 08 '19 at 15:14
123

There is a new annotation @Value in Spring 3.0.0M3. @Value support not only #{...} expressions but ${...} placeholders as well

AdrieanKhisbe
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    +1 If an example helps, here it is - @Value(value="#{'${server.env}'}") or simply @Value("#{'${server.env}'}") – Somu Oct 27 '11 at 20:14
31

<context:property-placeholder ... /> is the XML equivalent to the PropertyPlaceholderConfigurer.

Example: applicationContext.xml

<context:property-placeholder location="classpath:test.properties"/>  

Component class

 private @Value("${propertyName}") String propertyField;
shane lee
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    For me, this worked only if autowiring is enabled via `` For reference, I'm using spring via the `ApplicationContext`, not in a web context. – Mustafa Aug 06 '15 at 14:38
15

Another alternative is to add the appProperties bean shown below:

<bean id="propertyConfigurer"   
  class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="location" value="/WEB-INF/app.properties" />
</bean> 


<bean id="appProperties" 
          class="org.springframework.beans.factory.config.PropertiesFactoryBean">
        <property name="singleton" value="true"/>

        <property name="properties">
                <props>
                        <prop key="results.max">${results.max}</prop>
                </props>
        </property>
</bean>

When retrieved, this bean can be cast to a java.util.Properties which will contain a property named results.max whose value is read from app.properties. Again, this bean can be dependency injected (as an instance of java.util.Properties) into any class via the @Resource annotation.

Personally, I prefer this solution (to the other I proposed), as you can limit exactly which properties are exposed by appProperties, and don't need to read app.properties twice.

davek
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Dónal
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  • Works for me, too. But is there no other way to acces the properties from a PropertyPlaceholderConfigurer via the @Value annotation (when using multiple PropertyPlaceholderConfigurer in several congif XML files.)? – Czar Jan 27 '11 at 11:51
11

As mentioned @Value does the job and it is quite flexible as you can have spring EL in it.

Here are some examples, which could be helpful:

//Build and array from comma separated parameters 
//Like currency.codes.list=10,11,12,13
@Value("#{'${currency.codes.list}'.split(',')}") 
private List<String> currencyTypes;

Another to get a set from a list

//If you have a list of some objects like (List<BranchVO>) 
//and the BranchVO has areaCode,cityCode,...
//You can easily make a set or areaCodes as below
@Value("#{BranchList.![areaCode]}") 
private Set<String> areas;

You can also set values for primitive types.

@Value("${amount.limit}")
private int amountLimit;

You can call static methods:

@Value("#{T(foo.bar).isSecurityEnabled()}")
private boolean securityEnabled;

You can have logic

@Value("#{T(foo.bar).isSecurityEnabled() ? '${security.logo.path}' : '${default.logo.path}'}")
private String logoPath;
carlspring
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Alireza Fattahi
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9

I need to have two properties files, one for production and an override for development (that will not be deployed).

To have both, a Properties Bean that can be autowired and a PropertyConfigurer, you can write:

<bean id="appProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
    <property name="singleton" value="true" />

    <property name="ignoreResourceNotFound" value="true" />
    <property name="locations">
        <list>
            <value>classpath:live.properties</value>
            <value>classpath:development.properties</value>
        </list>
    </property>
</bean>

and reference the Properties Bean in the PropertyConfigurer

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="properties" ref="appProperties" />
</bean>
DaWilli
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8

You also can annotate you class:

@PropertySource("classpath:/com/myProject/config/properties/database.properties")

And have a variable like this:

@Autowired
private Environment env;

Now you can access to all your properties in this way:

env.getProperty("database.connection.driver")
Alexis Gamarra
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7

Spring way:
private @Value("${propertyName}") String propertyField;

is a new way to inject the value using Spring's "PropertyPlaceholderConfigurer" class. Another way is to call

java.util.Properties props = System.getProperties().getProperty("propertyName");

Note: For @Value, you can not use static propertyField, it should be non-static only, otherwise it returns null. To fix it a non static setter is created for the static field and @Value is applied above that setter.

hi.nitish
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7

Before we get Spring 3 - which allows you to inject property constants directly into your beans using annotations - I wrote a sub-class of the PropertyPlaceholderConfigurer bean that does the same thing. So, you can mark up your property setters and Spring will autowire your properties into your beans like so:

@Property(key="property.key", defaultValue="default")
public void setProperty(String property) {
    this.property = property;
}

The Annotation is as follows:

@Retention(RetentionPolicy.RUNTIME) 
@Target({ElementType.METHOD, ElementType.FIELD})
public @interface Property {
    String key();
    String defaultValue() default "";
}

The PropertyAnnotationAndPlaceholderConfigurer is as follows:

public class PropertyAnnotationAndPlaceholderConfigurer extends PropertyPlaceholderConfigurer {

    private static Logger log = Logger.getLogger(PropertyAnnotationAndPlaceholderConfigurer.class);

    @Override
    protected void processProperties(ConfigurableListableBeanFactory beanFactory, Properties properties) throws BeansException {
        super.processProperties(beanFactory, properties);

        for (String name : beanFactory.getBeanDefinitionNames()) {
            MutablePropertyValues mpv = beanFactory.getBeanDefinition(name).getPropertyValues();
            Class clazz = beanFactory.getType(name);

            if(log.isDebugEnabled()) log.debug("Configuring properties for bean="+name+"["+clazz+"]");

            if(clazz != null) {
                for (PropertyDescriptor property : BeanUtils.getPropertyDescriptors(clazz)) {
                    Method setter = property.getWriteMethod();
                    Method getter = property.getReadMethod();
                    Property annotation = null;
                    if(setter != null && setter.isAnnotationPresent(Property.class)) {
                        annotation = setter.getAnnotation(Property.class);
                    } else if(setter != null && getter != null && getter.isAnnotationPresent(Property.class)) {
                        annotation = getter.getAnnotation(Property.class);
                    }
                    if(annotation != null) {
                        String value = resolvePlaceholder(annotation.key(), properties, SYSTEM_PROPERTIES_MODE_FALLBACK);
                        if(StringUtils.isEmpty(value)) {
                            value = annotation.defaultValue();
                        }
                        if(StringUtils.isEmpty(value)) {
                            throw new BeanConfigurationException("No such property=["+annotation.key()+"] found in properties.");
                        }
                        if(log.isDebugEnabled()) log.debug("setting property=["+clazz.getName()+"."+property.getName()+"] value=["+annotation.key()+"="+value+"]");
                        mpv.addPropertyValue(property.getName(), value);
                    }
                }

                for(Field field : clazz.getDeclaredFields()) {
                    if(log.isDebugEnabled()) log.debug("examining field=["+clazz.getName()+"."+field.getName()+"]");
                    if(field.isAnnotationPresent(Property.class)) {
                        Property annotation = field.getAnnotation(Property.class);
                        PropertyDescriptor property = BeanUtils.getPropertyDescriptor(clazz, field.getName());

                        if(property.getWriteMethod() == null) {
                            throw new BeanConfigurationException("setter for property=["+clazz.getName()+"."+field.getName()+"] not available.");
                        }

                        Object value = resolvePlaceholder(annotation.key(), properties, SYSTEM_PROPERTIES_MODE_FALLBACK);
                        if(value == null) {
                            value = annotation.defaultValue();
                        }
                        if(value == null) {
                            throw new BeanConfigurationException("No such property=["+annotation.key()+"] found in properties.");
                        }
                        if(log.isDebugEnabled()) log.debug("setting property=["+clazz.getName()+"."+field.getName()+"] value=["+annotation.key()+"="+value+"]");
                        mpv.addPropertyValue(property.getName(), value);
                    }
                }
            }
        }
    }

}

Feel free to modify to taste

Ricardo Gladwell
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5

A possible solutions is to declare a second bean which reads from the same properties file:

<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="/WEB-INF/app.properties" />
</bean> 

<util:properties id="appProperties" location="classpath:/WEB-INF/app.properties"/>

The bean named 'appProperties' is of type java.util.Properties and can be dependency injected using the @Resource attruibute shown above.

Dónal
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4

If you are stuck using Spring 2.5 you could define a bean for each of your properties and inject them using qualifiers. Like this:

  <bean id="someFile" class="java.io.File">
    <constructor-arg value="${someFile}"/>
  </bean>

and

@Service
public class Thing
      public Thing(@Qualifier("someFile") File someFile) {
...

Its not super readable but it gets the job done.

Nik
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2

Autowiring Property Values into Spring Beans:

Most people know that you can use @Autowired to tell Spring to inject one object into another when it loads your application context. A lesser known nugget of information is that you can also use the @Value annotation to inject values from a property file into a bean’s attributes. see this post for more info...

new stuff in Spring 3.0 || autowiring bean values ||autowiring property values in spring

Lucky
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2

For me, it was @Lucky's answer, and specifically, the line

AutowiredFakaSource fakeDataSource = ctx.getBean(AutowiredFakaSource.class);

from the Captain Debug page

that fixed my problem. I have an ApplicationContext-based app running from the command-line, and judging by a number of the comments on SO, Spring wires up these differently to MVC-based apps.

ben3000
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1

I think it's most convenient way to inject properties into bean is setter method.

Example:

package org.some.beans;

public class MyBean {
    Long id;
    String name;

    public void setId(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }
}

Bean xml definition:

<bean id="Bean1" class="org.some.beans.MyBean">
    <property name="id" value="1"/>
    <property name="name" value="MyBean"/>
</bean>

For every named property method setProperty(value) will be invoked.

This way is especially helpful if you need more than one bean based on one implementation.

For example, if we define one more bean in xml:

<bean id="Bean2" class="org.some.beans.MyBean">
    <property name="id" value="2"/>
    <property name="name" value="EnotherBean"/>
</bean>

Then code like this:

MyBean b1 = appContext.getBean("Bean1");
System.out.println("Bean id = " + b1.getId() + " name = " + b1.getName());
MyBean b2 = appContext.getBean("Bean2");
System.out.println("Bean id = " + b2.getId() + " name = " + b2.getName());

Will print

Bean id = 1 name = MyBean
Bean id = 2 name = AnotherBean

So, in your case it should look like this:

@Repository("personDao")
public class PersonDaoImpl extends AbstractDaoImpl implements PersonDao {

    Long maxResults;

    public void setMaxResults(Long maxResults) {
        this.maxResults = maxResults;
    }

    // Now use maxResults value in your code, it will be injected on Bean creation
    public void someMethod(Long results) {
        if (results < maxResults) {
            ...
        }
    }
}
Sergei Pikalev
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0

If you need more Flexibility for the configurations, try the Settings4jPlaceholderConfigurer: http://settings4j.sourceforge.net/currentrelease/configSpringPlaceholder.html

In our application we use:

  • Preferences to configure the PreProd- and Prod-System
  • Preferences and JNDI Environment variables (JNDI overwrites the preferences) for "mvn jetty:run"
  • System Properties for UnitTests (@BeforeClass annotation)

The default order which key-value-Source is checked first, is described in:
http://settings4j.sourceforge.net/currentrelease/configDefault.html
It can be customized with a settings4j.xml (accurate to log4j.xml) in your classpath.

Let me know your opinion: settings4j-user@lists.sourceforge.net

with friendly regards,
Harald

Harald Brabenetz
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-1

Use Spring's "PropertyPlaceholderConfigurer" class

A simple example showing property file read dynamically as bean's property

<bean id="placeholderConfig"
        class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>/WEB-INF/classes/config_properties/dev/database.properties</value>
        </list>
    </property> 
</bean>

<bean id="devDataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
    <property name="driverClass" value="${dev.app.jdbc.driver}"/>
    <property name="jdbcUrl" value="${dev.app.jdbc.url}"/>
    <property name="user" value="${dev.app.jdbc.username}"/>
    <property name="password" value="${dev.app.jdbc.password}"/>
    <property name="acquireIncrement" value="3"/>
    <property name="minPoolSize" value="5"/>
    <property name="maxPoolSize" value="10"/>
    <property name="maxStatementsPerConnection" value="11000"/>
    <property name="numHelperThreads" value="8"/>
    <property name="idleConnectionTestPeriod" value="300"/>
    <property name="preferredTestQuery" value="SELECT 0"/>
</bean> 

Property File

dev.app.jdbc.driver=com.mysql.jdbc.Driver

dev.app.jdbc.url=jdbc:mysql://localhost:3306/addvertisement

dev.app.jdbc.username=root

dev.app.jdbc.password=root

ravi ranjan
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Easiest way in Spring 5 is to use @ConfigurationProperties here is example https://mkyong.com/spring-boot/spring-boot-configurationproperties-example/

Vikrant Chaudhary
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use @PropertySource("classpath:XX.properties") on your configuration class. XX=file_name enter image description here