通过反射访问子类中超类的私有成员变量

Question

I have this class that is RMIserviceexporter basically this class is spring remoting now in this there is a int variable named registry port

private int registryPort = Registry.REGISTRY_PORT; // which is set to 1099

and it has setter methods

public void setRegistryPort(int registryPort) {
    this.registryPort = registryPort;
}

now I have extended this class in later stages that is have i have created a new class abcexpoerter which basically extend RMIserviceexporter , I have to access this registryPort variable of RMIserviceexporter that is the variable name registryPort but i can not access this variable since there is no getter method defined in the parent class now please advise me can i access this private variable value in the extended lass through reflection

   class abcexpoter extends RMIServiceExporter
        {
            // now in this class i want to access the registerPort variable value  please advise how can i //access this registry port variable inside this class
        }

Answer 1

You can , but you shouldn't . The member is presumably private for a reason .

This is covered in the Class and java.lang.reflect package documentation: You get the field via getDeclaredField , then force it accessible using setAccessible , then use the relevant getXyz method from Field ( getInt , getString , whatever) to get its value.

For instance, since it's an int :

Field field = TheClass.class.getDeclaredField("registryPort");
field.setAccessible(true);
int port = field.getInt(this);