How can I inject a property value into a Spring Bean which was configured using annotations?

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

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")

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

Personally I love this new way in Spring 3.0 [from the docs][1]:

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();
}


[1]:

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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) {
...
}
}
}

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.

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;

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][1] I wrote about this for a little more info.

[1]:

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Easiest way in Spring 5 is to use `@ConfigurationProperties` here is example

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use @PropertySource("classpath:XX.properties") on your configuration class.
XX=file_name
[![enter image description here][1]][1]


[1]: