类对象 与 类的对象

Class<?> class1 = Class.forName("d01_student.Student");

Class<?> class1 = forName("d01_student.Student");  //获取类对象
class1.getName()                                                         //d01_student.Student
class1.getSimpleName());											  //Student
class1.getPackage());											  		  //package d01_student
class1.getPackage().getName());								  //d01_student
class1.getSuperclass());                                                //class java.lang.Object
Class<?>[] interfaces = class1.getInterfaces();              //继承的接口

//获取构造方法
        Class<?> class1 = forName("d01_student.Student");
 //获取所有构造方法
        Constructor<?>[] constructors = class1.getConstructors();
//获取单个构造方法
        Constructor<?> constructor = class1.getConstructor(String.class, int.class, String.class);

Method[] methods = class1.getMethods();

Method[] declaredMethods = class1.getDeclaredMethods();

Method methodShow1 = class1.getMethod("show");

Class<?> class1 = Class.forName("d01_student.Student");
Student stu1 = (Student) class1.newInstance();

//        Student s1 = (Student) class3.newInstance("夏雨荷",18,"女");   ???????????///是错误的，没有这种方法
/*要想获得有参数的构造方法必须
1.先Class.forName()获取类的对象
2.再获取带某个参数的构造方法
3.再用这个constructor ，newInstance一个对象，如下：*/

System.out.println("获取单个构造方法");
        Constructor<?> constructor = class1.getConstructor(String.class, int.class, String.class);
        Student student = (Student) constructor.newInstance("大明", 12, "男");
        System.out.println(student);

Student{name='大明', age=12, gender='男'}

        Constructor<?> constructor2 = class1.getConstructor();
        Student student2 = (Student) constructor2.newInstance();
        System.out.println(student2.toString());

无参构造执行了...
Student{name='null', age=0, gender='null'}

Student s3 = (Student) class1.newInstance();
System.out.println(s3.toString());

Student{name='null', age=0, gender='null'}

//Method methodShow2 = class1.getMethod("show", String.class);
Method methodShow1 = class1.getMethod("show");
Student stu1 = (Student) class1.newInstance();
methodShow1.invoke(stu1);

这里是show的无参数方法：姓名:null 年龄:0 性别:null

Process finished with exit code 0

Method method4 = class1.getDeclaredMethod("privateMethod");
        //设置访问权限失效
        method4.setAccessible(true);
        method4.invoke(stu1);

public static void main(String[] args) throws Exception {
Properties properties = new Properties();
        invokeAny(properties,"setProperty",new Class[]{String.class,String.class},"username","zhangsan");
        System.out.println(properties.toString());
}


public static Object invokeAny(Object obj, String methodName, Class<?>[] paramsType, Object... args)throws Exception{
        Class<?> class1 = obj.getClass();
        Method method = class1.getMethod(methodName, paramsType);
        return method.invoke(obj, args);
    }

Method staticMethod = class1.getMethod("staticMethod");
        staticMethod.invoke( null);

public static void reflectOp6() throws Exception{
        //1.获取对象
        Class<?> class1 = forName("d01_student.Student");
        //使用反射给属性赋值
        Field name = class1.getDeclaredField("name");
        //访问权限失效
        name.setAccessible(true);
        Student stu1 = (Student) class1.newInstance();
        name.set(stu1,"大明");
        System.out.println(name.get(stu1));
    }