034-安全开发-JavaEE应用&反射机制&攻击链&类对象&成员变量方法&构造方法#

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public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException {
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    Class aClass = Class.forName("com.example.reflectdemo1.User");
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    //1.获取公共的成员变量
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    Field[] fields1 = aClass.getFields();
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    for(Field fd:fields1){
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        System.out.println(fd);
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    }
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    //2.获取所有的成员变量
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    Field[] fields = aClass.getDeclaredFields();
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    for(Field fd:fields){
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        System.out.println(fd);
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    }
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    //3.获取单个的公共成员变量
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    Field name = aClass.getField("name");
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    System.out.println(name);
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    //4.获取单个的成员变量
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    Field gender = aClass.getDeclaredField("gender");
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    System.out.println(gender);
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    //5.获取公共的成员变量age的值并修改
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    User u = new User();
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    Field field=aClass.getField("age");
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    //取值
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    Object a=field.get(u);
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    System.out.println(a);
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    //赋值
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    field.set(u,32);
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    Object aa=field.get(u);
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    System.out.println(aa);
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}

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public class GetConstructor {
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    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException {
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        Class aClass = Class.forName("com.example.reflectdemo1.User");
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        //1.获取公共的构造方法
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        Constructor[] constructors = aClass.getConstructors();
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        for (Constructor con1 : constructors) {
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            System.out.println(con1);
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        }
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        //2.获取所有的构造方法
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        Constructor[] constructors2 = aClass.getDeclaredConstructors();
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        for (Constructor con2 : constructors2) {
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            System.out.println(con2);
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        }
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        //3.获取单个的公共的构造方法
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        Constructor constructor = aClass.getConstructor(String.class);
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        System.out.println(constructor);
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        //4.获取单个的构造方法
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        Constructor con3 = aClass.getDeclaredConstructor(String.class, int.class);
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        System.out.println(con3);
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        //5.对私有构造方法进行操作
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        Constructor con4 = aClass.getDeclaredConstructor(String.class, int.class);
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        con4.setAccessible(true); // 临时开启访问权限
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        User uu = (User) con4.newInstance("xiaodigaygay", 40); // 创建对象
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        System.out.println(uu);
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        //6.对公共构造方法进行操作(一个参数String)
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        Constructor con5 = aClass.getConstructor(String.class);
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        con5.newInstance("xiaodigaygay");
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    }
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}

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public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
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    Class aClass = Class.forName("com.example.reflectdemo1.User");
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    //1.获取包括继承的公共成员方法
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    Method[] methods = aClass.getMethods();
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    for(Method me:methods){
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        System.out.println(me);
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    }
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    //2.获取不包括继承的所有成员方法
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    Method[] methods1 = aClass.getDeclaredMethods();
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    for(Method me:methods1){
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        System.out.println(me);
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    }
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    //3.获取单个的成员方法
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    Method users = aClass.getDeclaredMethod("users", String.class,String.class);
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    System.out.println(users);
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    //4.调用成员方法
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    User u = new User();
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    Method users1 = aClass.getDeclaredMethod("users", String.class, String.class);
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    users1.invoke(u, "xiaodigay", "gay1"); // 等价于 u.users("xiaodigay", "gay1")
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}