load properties in spring

In Spring, you can load properties from a properties file using the `PropertySourcesPlaceholderConfigurer` bean. Here's an example configuration in XML:

<bean class="org.springframework.beans.factory.config.PropertySourcesPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>classpath:config.properties</value>
        </list>
    </property>
</bean>

This will load the `config.properties` file from the classpath. You can also specify multiple locations by adding more `value` elements to the list.

If you're using Java configuration, you can use the `@PropertySource` annotation:

@Configuration
@PropertySource("classpath:config.properties")
public class AppConfig {
    // ...
}

This will load the `config.properties` file from the classpath as well.

Once the properties are loaded, you can use them in your beans by using the `@Value` annotation:

@Component
public class MyBean {
    @Value("${my.property}")
    private String myProperty;

    // ...
}

This will inject the value of `my.property` from the properties file into the `myProperty` field of the `MyBean` class.