通过反射获取成员变量

package com.tain_8_23_01;

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

/*
 *      通过反射获取成员变量
 * Class.getField(String) 方法可以获取类中的指定字段（可见的）
 * 如果私有的可以用getDeclaedField("name")方法获取，通过set(obj,"XX")方法可以设定指定对象上该字段的值
 * 如果是私有的需要先调用setAccessible(true)设置访问权限，用获取的指定字段调用get(obj)可以获取指定对象中该字段的值
 * 
 */
public class Demo2_Field {

    public static void main(String[] args) throws Exception {
        Class clazz = Class.forName("com.tain_8_23_01.Person");
        Constructor c = clazz.getConstructor(String.class,int.class);   //获取有参的构造
        Person p = (Person) c.newInstance("孙悟空",500);                   //通过有参构造创建对象并赋值
//      
//      //NoSuchFieldException 私有成员不允许这样访问
//      Field f = clazz.getField("name");                               //获取姓名字段
//      f.set(p, "嬴政");                                                 //修改名字

        Field f1 = clazz.getDeclaredField("name");                      //暴力反射获取字段
        Field f2 = clazz.getDeclaredField("age");
        f1.setAccessible(true);                                         //去除私有权限
        f2.setAccessible(true);
        f1.set(p, "嬴政");
        f2.setInt(p, 2000);
        System.out.println(p);
    }

}


package com.tain_8_23_01;

public class Person {
    private String name;
    private int age;
    public Person(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }

    public Person() {
        super();
    }

    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 + "]";
    }


    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + age;
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }


    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Person other = (Person) obj;
        if (age != other.age)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}