code manipulation: reflection(Class API)

code-manipulation/reflection-example/src/main/java/org/example/annotation/App.java

@@ -1,8 +1,8 @@
-package org.example;
+package org.example.annotation;
 
 import java.util.Arrays;
 
-public class AnnotationApp {
+public class App {
 
     public static void main(String[] args) {
 

code-manipulation/reflection-example/src/main/java/org/example/annotation/Book.java

@@ -1,4 +1,4 @@
-package org.example;
+package org.example.annotation;
 
 
 @MyAnnotation(name = "lee", number = 20)

code-manipulation/reflection-example/src/main/java/org/example/annotation/MyAnnotation.java

@@ -1,4 +1,4 @@
-package org.example;
+package org.example.annotation;
 
 import java.lang.annotation.*;
 

code-manipulation/reflection-example/src/main/java/org/example/annotation/MyBook.java

@@ -1,4 +1,4 @@
-package org.example;
+package org.example.annotation;
 
 public class MyBook extends Book implements MyInterface{
 }

code-manipulation/reflection-example/src/main/java/org/example/annotation/MyInterface.java

@@ -1,4 +1,4 @@
-package org.example;
+package org.example.annotation;
 
 public interface MyInterface {
 }

code-manipulation/reflection-example/src/main/java/org/example/classapi/App.java

@@ -1,10 +1,9 @@
-package org.example;
+package org.example.classapi;
 
-import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
 
-public class ClassApiApp {
+public class App {
     public static void main( String[] args ) throws ClassNotFoundException {
 
 
@@ -100,7 +99,7 @@ public class ClassApiApp {
 //        System.out.println("============================");
 //
 //        // 문자열로 접근
-//        Class<?> bookClass2 = Class.forName("org.example.Book");
+//        Class<?> bookClass2 = Class.forName("org.example.annotation.Book");
 //        System.out.println(bookClass2.getName());
     }
 }

code-manipulation/reflection-example/src/main/java/org/example/classapi/Book.java

@@ -0,0 +1,35 @@
+package org.example.classapi;
+
+public class Book {
+
+    private static String B = "BOOK";
+
+    private static final String C = "BOOK";
+
+    private String a = "a";
+
+    public String d = "d";
+
+    protected String e = "e";
+
+    public Book() {
+    }
+
+    public Book(String a, String d, String e) {
+        this.a = a;
+        this.d = d;
+        this.e = e;
+    }
+
+    private void f() {
+        System.out.println("f");
+    }
+
+    public void g() {
+        System.out.println("g");
+    }
+
+    public int h() {
+        return 100;
+    }
+}

code-manipulation/reflection-example/src/main/java/org/example/classapi2/App.java

@@ -0,0 +1,56 @@
+package org.example.classapi2;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+public class App {
+
+    public static void main(String[] args) throws Exception {
+        /**
+         * Class API : 클래스 정보 수정, 실행 하기
+         */
+
+
+        // 메소드 실행하기
+        Class<?> bookClass = Class.forName("org.example.classapi2.Book");
+        Book book = (Book) bookClass.getConstructor().newInstance();
+
+        Method c = Book.class.getDeclaredMethod("c");
+        c.setAccessible(true);
+        c.invoke(book);
+
+        Method sum = Book.class.getDeclaredMethod("sum", int.class, int.class);
+        int invoke = (int) sum.invoke(book, 1, 2);
+        System.out.println(invoke);
+
+
+//        // 필드 값 접근/수정하기
+//        Field a = Book.class.getDeclaredField("A");
+//        System.out.println(a.get(null)); // static 필드 이므로 null
+//        a.set(null, "AAAAAA");
+//        System.out.println(a.get(null));
+//
+//
+//        Class<?> bookClass = Class.forName("org.example.classapi2.Book");
+//        Book book = (Book) bookClass.getConstructor().newInstance();
+//
+//        Field b = Book.class.getDeclaredField("B");
+//        b.setAccessible(true); // private 필드 이므로 접근 할 수 있도록 변경
+//        System.out.println(b.get(book)); // 특정 인스턴스가 필요
+//        b.set(book, "BBBBBB");
+//        System.out.println(b.get(book));
+
+
+//        // 생성자로 인스턴스 만들기
+//        Class<?> bookClass = Class.forName("org.example.classapi2.Book");
+//        Constructor<?> constructor = bookClass.getConstructor();
+//        Constructor<?> constructor1 = bookClass.getConstructor(String.class);
+//        Book book = (Book) constructor.newInstance();
+//        Book book1 = (Book) constructor1.newInstance("myBook");
+//
+//        System.out.println(book);
+//        System.out.println(book1);
+    }
+}

code-manipulation/reflection-example/src/main/java/org/example/classapi2/Book.java

@@ -0,0 +1,23 @@
+package org.example.classapi2;
+
+public class Book {
+
+    public static String A = "A";
+
+    private String B = "B";
+
+    public Book() {
+    }
+
+    public Book(String b) {
+        B = b;
+    }
+
+    private void c() {
+        System.out.println("C");
+    }
+
+    public int sum(int left, int right) {
+        return left + right;
+    }
+}

code-manipulation/reflection-example/src/test/java/org/example/ClassApiAppTest.java

@@ -1,20 +0,0 @@
-package org.example;
-
-import static org.junit.Assert.assertTrue;
-
-import org.junit.Test;
-
-/**
- * Unit test for simple App.
- */
-public class ClassApiAppTest
-{
-    /**
-     * Rigorous Test :-)
-     */
-    @Test
-    public void shouldAnswerWithTrue()
-    {
-        assertTrue( true );
-    }
-}