Java反射 基础

import java.lang.reflect.Constructor;import java.lang.reflect.Field;import java.lang.reflect.Method;class ReflectPoint {private int x;public int y;public ReflectPoint(int x, int y) {super();this.x = x;this.y = y;}}public class Test {public static void main(String[] args) throws Exception {//Class类String str1 = "abc";Class cls1 = Class.forName("java.lang.String");Class cls2 = String.class;Class cls3 = str1.getClass();System.out.println(cls1 == cls2); //trueSystem.out.println(cls2 == cls3); //trueSystem.out.println(int.class.isPrimitive()); //基本类型, trueSystem.out.println(int.class == Integer.TYPE); //Integer对应的基本类型字节码, trueSystem.out.println("---------");//构造函数的反射Constructor constructor1 = cls1.getDeclaredConstructor(String.class);String str2 = (String) constructor1.newInstance(new String("ccc"));System.out.println(str2);System.out.println("---------");//成员变量的反射ReflectPoint pt1 = new ReflectPoint(3, 5);Field fieldY = pt1.getClass().getField("y"); //getField要是共有的字段，fieldY是字节码System.out.println(fieldY.get(pt1));Field fieldX = pt1.getClass().getDeclaredField("x"); //getDeclaredField所有声明的都有fieldX.setAccessible(true);  //暴力反射System.out.println(fieldX.get(pt1));System.out.println("---------");//函数方法的反射String str3 = "xyz123";Method methodCharAt = String.class.getMethod("charAt", int.class);System.out.println(methodCharAt.invoke(str3, 1));System.out.println("---------");}}/*输出truetrue */