Spring Annotations - Injecting Map of Objects

Question

Using XML annotation , I am injecting a map using the below config -

 <bean id = "customerfactory" class = "com.brightstar.CustomerFactory"> <property name = "getCustomerMap"> <map key-type = "java.lang.String" value-type = "com.brightstar.CustomerImpl"> <entry key = "DEFAULT" value-ref = "getDefaultImpl"></entry> <entry key = "PERSON" value-ref = "getPersonImpl"></entry> <entry key = "COMPANY" value-ref = "getCompanyImpl"></entry> </map> </property> </bean>

I have created 3 beans - DefaultImpl , PersonImpl and CompanyImpl. How can I inject these as a map using Spring Annotation?

EDIT: For now , I have performed the below but not sure if it is the recommended approach

private Map<String, CustomerImpl> getCustomerMap ; @Autowired private GetDefaultImpl getDefaultImpl; @Autowired private GetPersonImpl getPersonImpl; @Autowired private GetCompanyImpl getCompanyImpl; private static final String DEFAULT = "DEFAULT"; private static final String COM = "PERSON"; private static final String SOM = "COMPANY"; @PostConstruct public void init(){ getCustomerMap = new LinkedHashMap<String,CustomerImpl>(); getCustomerMap.put(DEFAULT, getDefaultImpl); getCustomerMap.put(PERSON, getPersonImpl); getCustomerMap.put(COMPANY, getCompanyImpl); }

Sundararaj Govindasamy · Accepted Answer · 2016-10-06 22:45:50Z

1.Inject a Map which contains Objects, (Using Java Config)

You can do like this...

@Configuration public class MyConfiguration { @Autowired private WhiteColourHandler whiteColourHandler; @Bean public Map<ColourEnum, ColourHandler> colourHandlers() { Map<ColourEnum, ColourHandler> map = new EnumMap<>(); map.put(WHITE, whiteColourHandler); //put more objects into this map here return map; } }

====================

2.Inject a Map which contains Strings (Using properties file)

You can inject String values into a Map from the properties file using the @Value annotation and SpEL like this.

For example, below property in the properties file.

propertyname={key1:'value1',key2:'value2',....}

In your code,

@Value("#{${propertyname}}") private Map<String,String> propertyname;

Note: 1.The hashtag as part of the annotation.

 2.Values must be quotes, else you will get SpelEvaluationException

Thank you. In my case , I have to inject Objects which cannot be present in property file.
Thank you , this helps. Can you please comment on my approach as well? I'll accept the answer.
I am not sure, @Postconstruct is best practice to initialize bean or manage lifecycle of bean,because it is JEE standard, but not for injecting dependencies.But, Yes, best practices are not rules.

so-random-dude · Accepted Answer · 2016-10-07 03:31:06Z

Just adding my 2 cents. As far as I understood, you are implementing factory pattern , switching between the implementations at runtime. So, it is code, not a configuration, ideal place for that to be in is code itself, not the properties file. I would go with the first approach that Sundararaj Govindasamy suggested. I don't see any problem in @postConstruct method as well. But I would go with the former as its cleaner.

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