리플렉션 - 클래스와 메타데이터

package reflection.data;

public class BasicData {

    public String publicField;
    private int privateField;

    public BasicData() {
        System.out.println("BasicData.BasicData");
    }

    private BasicData(String data) {
        System.out.println("BasicData.BasicData: " + data);
    }

    public void call() {
        System.out.println("BasicData.call");
    }

    public String hello(String str) {
        System.out.println("BasicData.hello");
        return str + " hello";
    }

    private void privateMethod() {
        System.out.println("BasicData.privateMethod");
    }

    void defaultMethod() {
        System.out.println("BasicData.defaultMethod");
    }

    protected void protectedMethod() {
        System.out.println("BasicData.protectedMethod");
    }
}

 

 

- BasicV1

package reflection;

import reflection.data.BasicData;

public class BasicV1 {

    public static void main(String[] args) throws ClassNotFoundException {
        // 클래스 메타데이터 조회 방법 3가지

        // 1. 클래스에서 찾기
        Class<BasicData> basicDataClass1 = BasicData.class;
        System.out.println("basicDataClass1 = " + basicDataClass1);

        // 2. 인스턴스에서 찾기
        BasicData basicInstance = new BasicData();
        Class<? extends BasicData> basicDataClass2 = basicInstance.getClass();
        System.out.println("basicDataClass2 = " + basicDataClass2);

        // 3. 문자로 찾기
        String className = "reflection.data.BasicData"; // 패키지명 주의
        Class<?> basicDataClass3 = Class.forName(className);
        System.out.println("basicDataClass3 = " + basicDataClass3);
    }
}

 

 

- BasicV2

package reflection;

import reflection.data.BasicData;

import java.lang.reflect.Modifier;
import java.util.Arrays;

public class BasicV2 {

    public static void main(String[] args) {
        Class<BasicData> basicData = BasicData.class;

        System.out.println("basicData.getName() = " + basicData.getName());
        System.out.println("basicData.getSimpleName() = " + basicData.getSimpleName());
        System.out.println("basicData.getPackage() = " + basicData.getPackage());

        System.out.println("basicData.getSuperclass() = " + basicData.getSuperclass());
        System.out.println("basicData.getInterfaces() = " + Arrays.toString(basicData.getInterfaces()));

        System.out.println("basicData.isInterface() = " + basicData.isInterface());
        System.out.println("basicData.isEnum() = " + basicData.isEnum());
        System.out.println("basicData.isAnnotation() = " + basicData.isAnnotation());

        int modifiers = basicData.getModifiers();
        System.out.println("basicData.getModifiers() = " + modifiers);
        System.out.println("isPublic = " + Modifier.isPublic(modifiers));
        System.out.println("Modifier.toString() = " + Modifier.toString(modifiers));
    }
}