How use SpEL result as @Value key

Question

In my springboot application i want use @Value to read some configure,but this configure's used in many other methods,so i want define configure's key as a constant.This is the code:

@Component
public class InstanceConfig {

    private static final String CONFIGURE_KEY = "SUPPORT_MANAGER_PLANE_INSTANCES";

    @Value("${SUPPORT_MANAGER_PLANE_INSTANCES}")
    private String supportManageInstances;
    
    @ApolloConfigChangeListener(value = ConfigConsts.NAMESPACE_APPLICATION)
    public void processConfigureChange(ConfigChangeEvent event) {
        log.info("configure changed do somthing");
        ConfigChange configChange = event.getChange("SUPPORT_MANAGER_PLANE_INSTANCES");
    }
}

In this code variable "SUPPORT_MANAGER_PLANE_INSTANCES" used by @Value and processConfigureChange method,if need to modify this variable's value i need modify all refer this variable,so i want define one constant variable CONFIGURE_KEY @Value and processConfigureChange method use this variable.

maybe this can help : https://stackoverflow.com/a/30597973/11640072 — hirarqi, Nov 20 '20 at 03:14
*used in many other methods* Please provide more details. There's likely an existing pattern to use depending on the specifics of your case. — chrylis -cautiouslyoptimistic-, Nov 20 '20 at 04:01
Consider wrapping in an @Configuraton class so the value is injected within a single class. Then inject the configuration class in the other classes which need to know about `namespace`. The config class provides a simple getter method. — Andrew S, Nov 20 '20 at 04:37
if we get CONFIGURE_KEY’s value from a function like public String getConfigureKey() how should we define @Value("???")？ — TongChen, Nov 20 '20 at 07:18

score 1 · Answer 1 · answered Nov 20 '20 at 07:16

Thans @hirarqi's help

@Component
public class InstanceConfig {

    private static final String CONFIGURE_KEY = "SUPPORT_MANAGER_PLANE_INSTANCES";

    @Value("${" + CONFIGURE_KEY + "}")
    private String supportManageInstances;
    
    @ApolloConfigChangeListener(value = ConfigConsts.NAMESPACE_APPLICATION)
    public void processConfigureChange(ConfigChangeEvent event) {
        log.info("configure changed do somthing");
        ConfigChange configChange = event.getChange(CONFIGURE_KEY);
    }
}

How use SpEL result as @Value key

1 Answers1