反射API

package com.iotek.classtype;

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

public class ReflectionDemo {
  public static void main(String[] args) throws Exception {
      //获取PerSon类所关联的class对象
      Class<?>class1=Class.forName("com.iotek.classtype.PerSon");
     /* //通过反射机制来构造一个PerSon的实例对象(会默认调用无参数的构造方法)
      PerSon perSon=(PerSon)class1.newInstance();*/
      
      //调用指定的构造方法来构造对象(会调用无参数的构造方法)
      /*Constructor<?> perSon2=class1.getConstructor(new Class[] {});
      PerSon perSon=(PerSon) perSon2.newInstance(new Object[] {});
      System.out.println(perSon);*/
      
      //调用指定的构造方法来构造对象(带参数的构造方法)
      Constructor<?> perSon2=class1.getConstructor(new Class[] {String.class,int.class});
      PerSon perSon=(PerSon) perSon2.newInstance(new Object[] {"张三",20});
      System.out.println(perSon);
      
      //获取class对象所指定的所有方法,包括私有的
      Method[] methods=class1.getDeclaredMethods();
      for (Method method : methods) {
        System.out.println(method.getName());
    }
      
      
      /*//获取class对象所指定的方法,包括私有的(method.setAccessible(true)),破坏面向对象的封装性
      Method method=class1.getDeclaredMethod("toString",new Class[] {});
      System.out.println(method);
      
      //方法的调用
     String string= (String) method.invoke(perSon, new Object[] {});
    System.out.println(string);*/
      
      //获取class对象所指定属性,包括私有的
      Field field=class1.getDeclaredField("name");
      field.setAccessible(true);
      field.set(perSon, "tantanll");
      System.out.println(field.get(perSon));
      
      
}
}

 class PerSon{
    private String name;
    private int age;
    
    
    public PerSon() {
        
    }
    public PerSon(String name, int age) {
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "PerSon [name=" + name + ", age=" + age + "]";
    }
    
}