基本反射了解

package cn.wh;
/**
 * java.lang.Class
 * @author 王恒
 * @time 2016年11月2日 上午10:39:25
 */
public class RedlectTest {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        Cat cat=new Cat();System.out.println("--------------------------");
        
        Class c1=Class.forName("cn.wh.Cat");
        Class c2=Cat.class;
        Class c3=cat.getClass();
        
        System.out.println(c1.getName());
        System.out.println(c1.getSimpleName());
        //返回一个包含某些 Class 对象的数组，这些对象表示属于此 Class 对象所表示的类的成员的所有公共类和接口。
        System.out.println(c1.getClasses());
        System.out.println(c1.getPackage());
        System.out.println(c1.getModifiers());
        System.out.println(c1.getInterfaces());
        System.out.println("接口数量 "+c1.getInterfaces().length);
        System.out.println(c1.getSuperclass().getName());
        System.out.println("实例化  "+c1.newInstance());
    }
}

package cn.constructor;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

public class TestConstructor {

    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, SecurityException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        Class claxx=Class.forName("cn.wh.Cat");
        //查看有几个构造方法
        Constructor[] cs=claxx.getConstructors();
        System.out.println("有public几个构造方法   "+cs.length);
        Constructor[] cs2=claxx.getDeclaredConstructors();
        System.out.println("总共有几个构造方法   "+cs2.length);
        //暴力反射，即没有public修饰的构造方法，使其能够创建构造方法
        //c.setAccessible(true);
        //一个参数
        Constructor c=claxx.getDeclaredConstructor(String.class);
        System.out.println(c.getName()+"---"+c.getModifiers());
        //两个参数
        Constructor c2=claxx.getDeclaredConstructor(String.class,String.class);
        System.out.println(c.getName()+"---"+c.getModifiers());
        //实例化
        Object obj=c.newInstance("");
        System.out.println(obj+"---"+obj.getClass().getSimpleName());
        //Class<?>... parameterTypes  表示任意类型的可变参数
    }
}

package cn.Field;

import java.lang.reflect.Field;

import cn.wh.Cat;

public class TestField {

    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchFieldException, SecurityException {
        Class claxx=Class.forName("cn.wh.Cat");
        Cat cat=(Cat) claxx.newInstance();
        System.out.println("---------------------");
        //获取声明字段数组
        Field[] fs=claxx.getDeclaredFields();
        System.out.println("数组长度为   "+fs.length);
        
        for(Field f:fs){ 
            f.setAccessible(true);
            System.out.println(f.getName()+"--"+f.getModifiers()+"---"+f.get(cat));
        }
        
        //获取单个声明字段
        System.out.println("---------------------获取单个声明字段");
        Field f2=claxx.getDeclaredField("master");
        f2.setAccessible(true);
        System.out.println(f2.getName()+"--"+f2.getModifiers()+"---"+f2.get(cat));
        System.out.println(f2.getName()+"--"+f2.getModifiers()+"---"+f2.get(null));
        //若声明的字段是static 类型，则可以为f2.get(null),否则一律加对象
    }
}

package cn.wh;

public class Cat extends Animal{//,Maoke{
    //protected int age=50;
    protected String age="我的年龄50";
    public static String master="周老师";
    
    public Cat(){
        System.out.println("Cat.Cat(111)");
    }
    public Cat(String age,String sname){
         
    }
    
    Cat(String master,String sname,String age1){
        
    };
    
    public Cat(String sname){
        //super(); 写与不写 都存在！  如果写super()必须放在第一行
        super(sname);
        this.sname=sname;
        //super.eat();
        //System.out.println("Cat.Cat(222)"+super.age);
        //System.out.println("Cat.Cat(222)"+age);
    }
//    public float walk(String road){
//        System.out.println("Cat.walk()");
//        return 60f;
//    }
//    
     float walk(){
        System.out.println("Cat.walk()");
        m1();
        return 60f;
    }
     
     
     public void eat(){
            System.out.println("Cat.eat(111)");
        }
     void m1(){
         
     }
    
}

package cn.wh;



public  class Animal {
    
    protected  String  sname="";
    protected  int age=80;
    public static String master="杨老师";
    public Animal(){
        //System.out.println("Animal.Animal(111)");
        sname="";
    }
    
    public Animal(String sname){
        //System.out.println("Animal.Animal(222)");
    }
    
    public  void eat(){
        System.out.println("Animal.eat(111)");
    }
    
    public void eat(String foodName){
        System.out.println("Animal.eat(222)"+foodName);
    }
    
     String  eat(String foodName,int num){
        System.out.println("Animal.eat(333)"+foodName);
        return "好";
    }
    
    
    public void sleep(){
        
    }
     float walk(){
        System.out.println("Animal.walk()");
        return 30.5f;
    }
    
    
    
}

package cn.method;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import cn.wh.Cat;

public class TestMethod {
    
    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, SecurityException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {
        Cat cat=new Cat();
        
        Class claxx=Class.forName("cn.wh.Cat");
        //获取所有方法         包括实例方法，即对象方法    类名.getInstanll();
        Method[] ms=claxx.getDeclaredMethods();
        for(Method m:ms){
            System.out.println(m.getModifiers()+"--"+m.getName()+"--"+m.getParameterCount()+"--"+m.getReturnType());
        }
        
        Method me=claxx.getDeclaredMethod("walk",String.class);
        me.setAccessible(true);
        me.invoke(cat,"貓");
        
        Method me2=claxx.getDeclaredMethod("eat");
        me.setAccessible(true);
        me2.invoke(cat);
        
        claxx.getDeclaredMethod("m1").invoke(null);
    }
}