Se tudo o que você deseja fazer é acessar o valor do espaço reservado a partir do código, existe a @Valueanotação:
@Value("${settings.some.property}")
String someValue;
Para acessar espaços reservados no SPEL, use esta sintaxe:
#('${settings.some.property}')
Para expor a configuração a visualizações com o SPEL desativado, pode-se usar este truque:
package com.my.app;
import java.util.Collection;
import java.util.Map;
import java.util.Set;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.stereotype.Component;
@Component
public class PropertyPlaceholderExposer implements Map<String, String>, BeanFactoryAware {
ConfigurableBeanFactory beanFactory;
@Override
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = (ConfigurableBeanFactory) beanFactory;
}
protected String resolveProperty(String name) {
String rv = beanFactory.resolveEmbeddedValue("${" + name + "}");
return rv;
}
@Override
public String get(Object key) {
return resolveProperty(key.toString());
}
@Override
public boolean containsKey(Object key) {
try {
resolveProperty(key.toString());
return true;
}
catch(Exception e) {
return false;
}
}
@Override public boolean isEmpty() { return false; }
@Override public Set<String> keySet() { throw new UnsupportedOperationException(); }
@Override public Set<java.util.Map.Entry<String, String>> entrySet() { throw new UnsupportedOperationException(); }
@Override public Collection<String> values() { throw new UnsupportedOperationException(); }
@Override public int size() { throw new UnsupportedOperationException(); }
@Override public boolean containsValue(Object value) { throw new UnsupportedOperationException(); }
@Override public void clear() { throw new UnsupportedOperationException(); }
@Override public String put(String key, String value) { throw new UnsupportedOperationException(); }
@Override public String remove(Object key) { throw new UnsupportedOperationException(); }
@Override public void putAll(Map<? extends String, ? extends String> t) { throw new UnsupportedOperationException(); }
}
E, em seguida, use o expositor para expor propriedades a uma exibição:
<bean class="org.springframework.web.servlet.view.UrlBasedViewResolver" id="tilesViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.tiles2.TilesView"/>
<property name="attributesMap">
<map>
<entry key="config">
<bean class="com.my.app.PropertyPlaceholderExposer" />
</entry>
</map>
</property>
</bean>
Em vista, use as propriedades expostas como esta:
${config['settings.some.property']}
Esta solução tem a vantagem de poder confiar na implementação padrão de espaço reservado injetada pelo contexto: tag de propriedade-espaço reservado.
Agora, como observação final, se você realmente precisar capturar todas as propriedades de espaço reservado e seus valores, precisará canalizá-las através de StringValueResolver para garantir que os espaços reservados funcionem dentro dos valores da propriedade conforme o esperado. O código a seguir fará isso.
package com.my.app;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
import org.springframework.util.StringValueResolver;
public class AppConfig extends PropertyPlaceholderConfigurer implements Map<String, String> {
Map<String, String> props = new HashMap<String, String>();
@Override
protected void processProperties(ConfigurableListableBeanFactory beanFactory, Properties props)
throws BeansException {
this.props.clear();
for (Entry<Object, Object> e: props.entrySet())
this.props.put(e.getKey().toString(), e.getValue().toString());
super.processProperties(beanFactory, props);
}
@Override
protected void doProcessProperties(ConfigurableListableBeanFactory beanFactoryToProcess,
StringValueResolver valueResolver) {
super.doProcessProperties(beanFactoryToProcess, valueResolver);
for(Entry<String, String> e: props.entrySet())
e.setValue(valueResolver.resolveStringValue(e.getValue()));
}
// Implement map interface to access stored properties
@Override public Set<String> keySet() { return props.keySet(); }
@Override public Set<java.util.Map.Entry<String, String>> entrySet() { return props.entrySet(); }
@Override public Collection<String> values() { return props.values(); }
@Override public int size() { return props.size(); }
@Override public boolean isEmpty() { return props.isEmpty(); }
@Override public boolean containsValue(Object value) { return props.containsValue(value); }
@Override public boolean containsKey(Object key) { return props.containsKey(key); }
@Override public String get(Object key) { return props.get(key); }
@Override public void clear() { throw new UnsupportedOperationException(); }
@Override public String put(String key, String value) { throw new UnsupportedOperationException(); }
@Override public String remove(Object key) { throw new UnsupportedOperationException(); }
@Override public void putAll(Map<? extends String, ? extends String> t) { throw new UnsupportedOperationException(); }
}