Access properties file programmatically with Spring?

Question

We use the code below to inject Spring beans with properties from a properties file.

Answer 1

How about PropertiesLoaderUtils?

Resource resource = new ClassPathResource("/my.properties");
Properties props = PropertiesLoaderUtils.loadProperties(resource);

Answer 2

You can get your properties through Environment class. As documentation stands:

Properties play an important role in almost all applications, and may originate from a variety of sources: properties files, JVM system properties, system environment variables, JNDI, servlet context parameters, ad-hoc Properties objects, Maps, and so on. The role of the environment object with relation to properties is to provide the user with a convenient service interface for configuring property sources and resolving properties from them.

Having Environment as a env variable, simply call:

env.resolvePlaceholders("${your-property:default-value}")

You can get your 'raw' properties through:

env.getProperty("your-property")

It will search through all properties source that spring has registered.

You can either obtain Environment through:

• inject ApplicationContext by implementing ApplicationContextAware and then call getEnvironment() on context
• implement EnvironmentAware.

It's obtain through implementation of a class because properties are resolved on early stage of application startup, as they may be required for bean construction.

Read more on documentation: spring Environment documentation

Answer 3

This is the finest way I got it to work:

package your.package;

import java.io.IOException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PropertiesLoaderUtils;

public class ApplicationProperties {

    private Properties properties;

    public ApplicationProperties() {
        // application.properties located at src/main/resource
        Resource resource = new ClassPathResource("/application.properties");
        try {
            this.properties = PropertiesLoaderUtils.loadProperties(resource);
        } catch (IOException ex) {
            Logger.getLogger(ApplicationProperties.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public String getProperty(String propertyName) {
        return this.properties.getProperty(propertyName);
    }
}

Answer 4

I have done this and it has worked.

Properties props = PropertiesLoaderUtils.loadAllProperties("my.properties");
PropertyPlaceholderConfigurer props2 = new PropertyPlaceholderConfigurer();
props2.setProperties(props);

That should work.

Answer 5

This will resolve any nested properties.

public class Environment extends PropertyPlaceholderConfigurer {

/**
 * Map that hold all the properties.
 */
private Map<String, String> propertiesMap; 

/**
 * Iterate through all the Property keys and build a Map, resolve all the nested values before building the map.
 */
@Override
protected void processProperties(ConfigurableListableBeanFactory beanFactory, Properties props) throws BeansException {
    super.processProperties(beanFactory, props);

    propertiesMap = new HashMap<String, String>();
    for (Object key : props.keySet()) {
        String keyStr = key.toString();
        String valueStr = beanFactory.resolveEmbeddedValue(placeholderPrefix + keyStr.trim() + DEFAULT_PLACEHOLDER_SUFFIX);
        propertiesMap.put(keyStr, valueStr);
    }
} 

/**
 * This method gets the String value for a given String key for the property files.
 * 
 * @param name - Key for which the value needs to be retrieved.
 * @return Value
 */
public String getProperty(String name) {
    return propertiesMap.get(name).toString();
}

Answer 6

create .properties file in classpath of your project and add path configuration in xml`<context:property-placeholder location="classpath*:/*.properties" />`

in servlet-context.xml after that u can directly use your file everywhere