Java反射的基础使用

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啥也不说，直接上代码。

//性别枚举

public enum Sex{    Man, Woman;}

//抽象基类

public abstract class Person{    //定义人的基本属性,姓名 + 性别    public String name;    public Sex sex;}

//定义Lily

public class Lily extends Person{    //Lily,对女孩来说，年龄、体重、外号都是秘密    private int age = 20;    private int weight = 52;    private String alia = "Little fox";    public Lily()    {        this.name = "Lily";        this.sex = Sex.Woman;    }    /**     * 基本信息，访问权限 - 公共     *     * @return     */    public String getBasicInfo()    {        return "Name:" + name + ", Sex:" + sex.toString();    }    /**     * 扩展信息，访问权限 - 私有     *     * @return     */    private String getExpandInfo()    {        return "Age:" + age + ", " + "Weight:" + weight + "kg, " + "Alia:" + alia;    }}

//某人类

public class Someone extends Person{    private Someone(String name, Sex sex)    {        this.name = name;        this.sex = sex;    }    private void setFavouriteSports(String favouriteSports)    {        System.out.print(name + " favourite sports is " + favouriteSports);    }}

引用类

public class Reflection{    public static void main(String args[]) throws Exception    {        //反射的基本使用一, 常用反射写法一        Class cls = Lily.class;        Object object = cls.newInstance();        //常量的反射        Field age = cls.getDeclaredField("age");        age.setAccessible(true);        Field weight = cls.getDeclaredField("weight");        weight.setAccessible(true);        Field alia = cls.getDeclaredField("alia");        alia.setAccessible(true);        System.out.println("age == " + age.get(object));        System.out.println("weight == " + weight.get(object));        System.out.println("alia == " + alia.get(object));        //基本信息获取        Lily lily = new Lily();        System.out.println("basicInfo == " + lily.getBasicInfo());        //私有方法的反射        Method method = cls.getDeclaredMethod("getExpandInfo", null);        method.setAccessible(true);        System.out.println("ExpandInfo == " + method.invoke(object, null));        //反射的基本使用二, 常用反射写法二        Class cs = Class.forName("com.sample.Someone");        Constructor<Someone> constructor = cs.getDeclaredConstructor(String.class, Sex.class);        constructor.setAccessible(true);        //利用反射，调用私有构造器        Someone someone = constructor.newInstance("Junhui", Sex.Man);        Class someClass = someone.getClass();        Method setFav = someClass.getDeclaredMethod("setFavouriteSports", String.class);        setFav.setAccessible(true);        setFav.invoke(someone, "basketball");    }}

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