package com.crow;

import java.io.IOException;

import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

/**

* Created by CrowHawk on 17/2/8.

*/

public class ReflectTest {

public static void main(String[] args) throws Exception{

FieldReflect fr = refConstructor(1,2);

System.out.println(fr.toString());

refFieldChange(fr, "a");

System.out.println("fr.a = " + fr.a);

refFieldChange(fr, "str1");

System.out.println("fr.str1 = " + fr.str1);

}

public static FieldReflect refConstructor(int a, int b) throws Exception{//使用反射构造器创建对象

Class[] paralist = {int.class, int.class};

Constructor cons = FieldReflect.class.getDeclaredConstructor(paralist);

FieldReflect fr = (FieldReflect) cons.newInstance(a, b);

return fr;

}

public static void refFieldChange(FieldReflect fr, String fieldName) throws Exception{

//使用Field类改变类的实例域,如果是int型,全部设为3,如果是String类型,将String中的"b"改为"c"

Field field = fr.getClass().getDeclaredField(fieldName);

field.setAccessible(true);

if(field.getType() == int.class){

field.set(fr, 3);

}

else if(field.getType() == String.class) {

String string = (String) field.get(fr);

string.replace("b", "c");

field.set(fr, string);

}

else {

throw new IOException();

}

}

}