Spring: How to inject a value to static field?

Whiteship picture Whiteship · Aug 31, 2011 · Viewed 125k times · Source

With this class

@Component
public class Sample {

    @Value("${my.name}")
    public static String name;


}

If I try Sample.name, it is always 'null'. So I tried this.

public class Sample {

    public static String name;

    @PostConstruct
    public void init(){
        name = privateName;
    }

    @Value("${my.name}")
    private String privateName;

    public String getPrivateName() {
        return privateName;
    }

    public void setPrivateName(String privateName) {
        this.privateName = privateName;
    }  

}

This code works. Sample.name is set properly. Is this good way or not? If not, is there something more good way? And how to do it?

Answer

Tomasz Nurkiewicz picture Tomasz Nurkiewicz · Aug 31, 2011

First of all, public static non-final fields are evil. Spring does not allow injecting to such fields for a reason.

Your workaround is valid, you don't even need getter/setter, private field is enough. On the other hand try this:

@Value("${my.name}")
public void setPrivateName(String privateName) {
    Sample.name = privateName;
}  

(works with @Autowired/@Resource). But to give you some constructive advice: Create a second class with private field and getter instead of public static field.