反射的簡單的例子練習

	package reflect;
	import java.lang.reflect.Constructor;
	import java.lang.reflect.Field;
	import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
	
	/**
	 * 反射的學習
	 * @author hjsjy
	 *
	 */
	public class Test01 {
		public int a;
		private int b;
		private
 
 String cString;
		public String name;
		protected String dString;
		int d;
		public Test01() {
			System.out.println("構造方法");
		}
		private Test01(int a) {
			System.out.println("私有的構造方法"+a);
		}
		public Test01(int a,int b) {
			System.out.println("構造方法兩個引數");
		}
		//**************成員方法***************//
		public
 
 void show1(String s){
			System.out.println("呼叫了：公有的，String引數的show1(): s = " + s);
		}
		protected void show2(){
			System.out.println("呼叫了：受保護的，無參的show2()");
		}
		void show3(){
			System.out.println("呼叫了：預設的，無參的show3()");
		}
		private String show4(int age){
			System.out.println("呼叫了，私有的，並且有返回值的，int引數的show4(): age = "
 
 + age);
			return "abcd";
		}
		@Override
		public String toString() {
			return "Test01 [a=" + a + ", b=" + b + ", cString=" + cString + ", name=" + name + ", dString=" + dString
					+ ", d=" + d + "]";
		}
		public static void main(String[] args) throws Exception{
			Class<?> class1 = Class.forName("reflect.Test01");
			 System.out.println("------------------獲取構造方法並使用-----------------------------------");
			 Constructor<?>[] constructors = class1.getConstructors();
			 for(Constructor aConstructor :constructors) {
				 System.out.println(aConstructor);
			 }
			 System.out.println("---------------------------------------------------------------------------");
			 constructors = class1.getDeclaredConstructors();
			for(Constructor constructor: constructors) {
				System.out.println(constructor);
			}
			System.out.println("---------------------------------------------------------------------------");
			Constructor<?> declaredConstructor = class1.getDeclaredConstructor(int.class);
			System.out.println(declaredConstructor);
			declaredConstructor.setAccessible(true);
			Object newInstance = declaredConstructor.newInstance(1);
			System.out.println("--------------------獲取成員變數並呼叫----------------------------------------");
			Field[] fields = class1.getFields();
			for(Field f:fields) {
				System.out.println(f);
			}
			System.out.println("---------------------------------------------------------------------------");
			Field[] declaredFields = class1.getDeclaredFields();
			for(Field field :declaredFields) {
				System.out.println(field);
			}
			Field field = class1.getField("name");	
			System.out.println(field);
			Object newInstance2 = class1.getConstructor().newInstance();
			field.set(newInstance2, "hjsjy");
			Test01 test01=(Test01)newInstance2;
			System.out.println(test01.name);
			System.out.println("---------------------------------------------------------------------------");
			Field declaredField = class1.getDeclaredField("b");
			System.out.println(declaredField);
			declaredField.setAccessible(true);
			declaredField.set(newInstance2, 188);
			System.out.println(newInstance2);
			System.out.println("-------------------------獲取方法並掉呼叫-----------------------------------");
			Method[] methods = class1.getMethods();
			for(Method method:methods) {
				System.out.println(method);
			}
			Method[] declaredMethods = class1.getDeclaredMethods();
			for(Method method: declaredMethods) {
				System.out.println(method);
			}
			Method method = class1.getMethod("show1", String.class);
			System.out.println(method);
			Object newInstance3 = class1.getConstructor().newInstance();
			method.invoke(newInstance3, "hjsjy");
			Method declaredMethod = class1.getDeclaredMethod("show4", int.class);
			System.out.println(declaredMethod);
			declaredMethod.setAccessible(true);
			Object invoke = declaredMethod.invoke(newInstance3, 500);
			System.out.println(invoke);	
		}
	}

輸出結果

------------------獲取構造方法並使用-----------------------------------
public reflect.Test01(int,int)
public reflect.Test01()
---------------------------------------------------------------------------
public reflect.Test01(int,int)
private reflect.Test01(int)
public reflect.Test01()
---------------------------------------------------------------------------
private reflect.Test01(int)
私有的構造方法1
--------------------獲取成員變數並呼叫----------------------------------------
public int reflect.Test01.a
public java.lang.String reflect.Test01.name
---------------------------------------------------------------------------
public int reflect.Test01.a
private int reflect.Test01.b
private java.lang.String reflect.Test01.cString
public java.lang.String reflect.Test01.name
protected java.lang.String reflect.Test01.dString
int reflect.Test01.d
public java.lang.String reflect.Test01.name
構造方法
hjsjy
---------------------------------------------------------------------------
private int reflect.Test01.b
Test01 [a=0, b=188, cString=null, name=hjsjy, dString=null, d=0]
-------------------------獲取方法並掉呼叫-----------------------------------
public static void reflect.Test01.main(java.lang.String[]) throws java.lang.Exception
public java.lang.String reflect.Test01.toString()
public void reflect.Test01.show1(java.lang.String)
public final void java.lang.Object.wait() throws java.lang.InterruptedException
public final void java.lang.Object.wait(long,int) throws java.lang.InterruptedException
public final native void java.lang.Object.wait(long) throws java.lang.InterruptedException
public boolean java.lang.Object.equals(java.lang.Object)
public native int java.lang.Object.hashCode()
public final native java.lang.Class java.lang.Object.getClass()
public final native void java.lang.Object.notify()
public final native void java.lang.Object.notifyAll()
public static void reflect.Test01.main(java.lang.String[]) throws java.lang.Exception
public java.lang.String reflect.Test01.toString()
public void reflect.Test01.show1(java.lang.String)
protected void reflect.Test01.show2()
void reflect.Test01.show3()
private java.lang.String reflect.Test01.show4(int)
public void reflect.Test01.show1(java.lang.String)
構造方法
呼叫了：公有的，String引數的show1(): s = hjsjy
private java.lang.String reflect.Test01.show4(int)
呼叫了，私有的，並且有返回值的，int引數的show4(): age = 500
abcd

本文參考：https://blog.csdn.net/sinat_38259539/article/details/71799078?tdsourcetag=s_pcqq_aiomsg