作用

反射机制可以读和修改字节码文件

如何获取类的字节码

public class Test06 {public static void main(String[] args) {//第一种方式Class c=null;try {c=Class.forName("Bird");} catch (ClassNotFoundException e) {e.printStackTrace();}try {Object o=c.newInstance();System.out.println(o);} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}//第二种方式Bird bird=new Bird();Class cc=bird.getClass();try {Object o=cc.newInstance();System.out.println(o);} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}//第三种方式String s="hello word";Class a=s.getClass();Class ccc=String.class;try {Object o=ccc.newInstance();System.out.println(a==ccc);} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();}}
}
class Bird{public Bird() {System.out.println("无参数构造方法");}
}