Java反射系列--应用

原文网址：Java反射系列--应用_IT利刃出鞘的博客-CSDN博客

简介

本文用示例介绍Java反射的应用。

调用类的方法

package org.example.a;

import java.lang.reflect.Method;

class Human {
    private String name;
    private Integer age;

    public Human() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }


    public void sayCategory() {
        System.out.println("HUMAN");
    }

    public String sayHello(String name, Integer age) {
        return "名字:" + name + " " + "年龄:" + age;
    }
}


public class Demo {
    public static void main(String[] args) {
        Class<?> c = null;
        try {
            c = Class.forName("org.example.a.Human");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

        try {
            Method method = c.getMethod("sayHello", String.class, Integer.class);
            System.out.println(method.invoke(c.newInstance(), "Tony", 20));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

执行结果

名字:Tony 年龄:20

修改属性

package com.example.a;

import java.lang.reflect.Field;


public class Demo {
    public static void main(String[] args) {
        User user = new User();

        try {
            Class<? extends User> aClass = user.getClass();
            Field nameField = aClass.getDeclaredField("name");
            nameField.setAccessible(true);   //将name属性设置成可被外部访问
            nameField.set(user, "Tony");     //设置name属性内容
            
            System.out.println(user.getName());
            // 也可以这么写：
            // System.out.println(nameField.get(user));

            nameField.setAccessible(false);  //将name属性设置成不可被外部访问
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

class User {
    private String name;
    private Integer age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public void sayCategory() {
        System.out.println("HUMAN");
    }

    public String sayHello(String name, Integer age) {
        return "名字:" + name + " " + "年龄:" + age;
    }
}

执行结果

Tony

上边是文章的部分内容，为便于维护，全文已转移到此网址：Java反射系列-应用 - 自学精灵