LogInjector.java

package swag49.util;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;
import org.springframework.util.ReflectionUtils;

import java.lang.reflect.Field;

@Component
public class LogInjector implements BeanPostProcessor {
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }

    public Object postProcessBeforeInitialization(final Object bean, String beanName) throws BeansException {
        ReflectionUtils.doWithFields(bean.getClass(), new ReflectionUtils.FieldCallback() {
            public void doWith(Field field) throws IllegalArgumentException, IllegalAccessException {
                // make the field accessible if defined private
                ReflectionUtils.makeAccessible(field);
                if (field.getAnnotation(Log.class) != null) {
                    Logger log = LoggerFactory.getLogger(bean.getClass().getName());
                    field.set(bean, log);
                } else if (field.getAnnotation(DbLog.class) != null) {
                    String loggerName = "db." + bean.getClass().getName();
                    Logger log = LoggerFactory.getLogger(loggerName);
                    field.set(bean, log);
                }
            }
        });

        return bean;
    }
}