Is it possible to use Spring @Value, to map values from properties file to the HashMap?
Yes, it is. With a little help of code and Spel.
Firstly, consider this singleton Spring-bean (you should scan it):
@Component("PropertySplitter")
public class PropertySplitter {
/**
* Example: one.example.property = KEY1:VALUE1,KEY2:VALUE2
*/
public Map<String, String> map(String property) {
return this.map(property, ",");
}
/**
* Example: one.example.property = KEY1:VALUE1.1,VALUE1.2;KEY2:VALUE2.1,VALUE2.2
*/
public Map<String, List<String>> mapOfList(String property) {
Map<String, String> map = this.map(property, ";");
Map<String, List<String>> mapOfList = new HashMap<>();
for (Entry<String, String> entry : map.entrySet()) {
mapOfList.put(entry.getKey(), this.list(entry.getValue()));
}
return mapOfList;
}
/**
* Example: one.example.property = VALUE1,VALUE2,VALUE3,VALUE4
*/
public List<String> list(String property) {
return this.list(property, ",");
}
/**
* Example: one.example.property = VALUE1.1,VALUE1.2;VALUE2.1,VALUE2.2
*/
public List<List<String>> groupedList(String property) {
List<String> unGroupedList = this.list(property, ";");
List<List<String>> groupedList = new ArrayList<>();
for (String group : unGroupedList) {
groupedList.add(this.list(group));
}
return groupedList;
}
private List<String> list(String property, String splitter) {
return Splitter.on(splitter).omitEmptyStrings().trimResults().splitToList(property);
}
private Map<String, String> map(String property, String splitter) {
return Splitter.on(splitter).omitEmptyStrings().trimResults().withKeyValueSeparator(":").split(property);
}
}
Note: PropertySplitter class uses Splitter utility from Guava. Please refer to its documentation for further details.
Then, in some bean of yours:
@Component
public class MyBean {
@Value("#{PropertySplitter.map('${service.expiration}')}")
Map<String, String> propertyAsMap;
}
And finally, the property:
service.expiration = name1:100,name2:20
It's not exactly what you've asked, because this PropertySplitter works with one single property that is transformed into a Map, but I think you could either switch to this way of specifying properties, or modify the PropertySplitter code so that it matches the more hierarchical way you desire.
