import java.lang.reflect.Constructor;

import java.lang.reflect.Field;

public class ReflectTest {

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

  Class cls2 = Person.class;

  Constructor con2 = cls2.getConstructor(String.class,int.class,String.class);

  Person p2 = (Person)con2.newInstance("lisi",21,"w");

  Field field2 = cls2.getDeclaredField("name");

  field2.set(p2, "wangwu");

  String name = (String)field2.get(p2);

  System.out.println(name);

}

}

class Person {

private String name;

public int age;

public String sex;

public Person(String name, int age, String sex) {

  this.name = name;

  this.age = age;

  this.sex = sex;

}

}

修改name属性的值，总是修改不成功，前面修改age就成功了。

修改完打印结果:

{:soso__3110130392203091378_3:}

name是私有的，反射无法访问，用setAccessible（true）这个方法，暴力反射。