java反射代码案例

package com.bh.zoo;

public class Wolf extends Animal{
    public String name;
    public String color;
    protected String blood;
    private int age;

    public void eat(){
        System.out.println("狼吃肉");

    }
    public void eat(String food){
        System.out.println("狼吃"+food);
    }
    private void sleep(){
        System.out.println("sleep....");
    }

}

package com.bh.demo;

import com.bh.zoo.Wolf;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Test {
    public static void main(String[] args) {
        System.out.println("start-----------");

        //获得类对象，方法1
        Class clz1=null;
        try {
             clz1 = Class.forName("com.bh.zoo.Wolf");
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
        //获得类的所有成员属性
        //通过getFields方法获得是所有public的成员属性
       /* Field[] fields = clz1.getFields();
        for (int i = 0; i < fields.length; i++) {
            Field f= fields[i];
            System.out.println(f.getName());
        }*/

        // 通过getDeclaredFields方法，可以获得所有的成员属性
      /*  Field[] declaredFields = clz1.getDeclaredFields();
        for (int i = 0; i < declaredFields.length; i++) {
            System.out.println(declaredFields[i].getName());
        }*/



        //获得类对象，方法2(同1)
        Class<Wolf> clz2 = Wolf.class;
      /*  Field[] fields = clz2.getFields();
        for (int i = 0; i < fields.length; i++) {
            Field f= fields[i];
            System.out.println(f.getName());
        }*/


        //获得类对象，方法3
        Wolf northWolf = new Wolf();
        Class clz3 = northWolf.getClass();
      /*  Field[] fields = clz3.getFields();
        for (int i = 0; i < fields.length; i++) {
            Field f= fields[i];
            System.out.println(f.getName());
        }*/
      /*  Field[] declaredFields = clz3.getDeclaredFields();
        for (int i = 0; i < declaredFields.length; i++) {
            System.out.println(declaredFields[i].getName());}*/

        //获得成员方法(包括父类)公共的
      /*  Method[] methods = clz2.getMethods();
        for (Method m:methods) {
            System.out.println(m.getName());
        }*/

        //获得成员方法（自己）
      /*  Method[] declaredMethods = clz2.getDeclaredMethods();
        for (Method m:declaredMethods) {
            System.out.println(m.getName());
        }*/

        Wolf w1 = null;
        Wolf w2 = null;
        Wolf w3 = null;

        try {
            w1 = (Wolf) clz2.newInstance();
            w2 = (Wolf) clz2.newInstance();
            w3 = (Wolf) clz2.newInstance();
        } catch (InstantiationException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }
        //w1.eat();
        w2.eat("草");

        try {
            //获取指定无参方法，通过w2对象调用
            /*Method eatMethod = clz2.getMethod("eat", null);
            eatMethod.invoke(w2,null);*/
            //获取指定有参方法，通过w1对象赋值调用
            Method eatMethod = clz2.getMethod("eat", String.class);
            eatMethod.invoke(w1,"苹果");
        } catch (NoSuchMethodException e) {
            throw new RuntimeException(e);
        } catch (InvocationTargetException e) {
            throw new RuntimeException(e);
        } catch (IllegalAccessException e) {
            throw new RuntimeException(e);
        }

        System.out.println("end-----------");

    }
}