反射
1. 获取类对象的三种方法
public static void method2() throws ClassNotFoundException {
//获取类对象方法 1
Class<Monkey> c1 = Monkey.class;
//获取类对象方法 2
Monkey class2 = new Monkey();
Class<? extends Monkey> c2 = class2.getClass();
//获取类对象方法 3
Class<?> c3 = Class.forName("com.deu.javasm.day0310.Monkey");
}
2. 获取构造器
public static void method3() throws ClassNotFoundException, NoSuchMethodException {
Class<?> c1 = Class.forName("com.deu.javasm.day0310.Monkey");
//获取Public修饰的构造器
Constructor<?>[] constructors = c1.getConstructors();
//获取某个指定public修饰的构造器
Constructor<?> constructor = c1.getConstructor();
//获取所有的构造器包含private
Constructor<?>[] declaredConstructors = c1.getDeclaredConstructors();
//获取某个指定的构造器
Constructor<?> declaredConstructor = c1.getDeclaredConstructor();
}
3. 用反射操作构造器,创建对象
public static void method4() throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
//获取类对象
Class<?> c1 = Class.forName("com.deu.javasm.day0310.Monkey");
//获取构造器
Constructor<?> declaredConstructor = c1.getDeclaredConstructor();
//创建对象(访问权限)
declaredConstructor.setAccessible(true);
Object o = declaredConstructor.newInstance();
System.out.println(o);
}
4. 使用反射操作成员变量
public static void method5() throws ClassNotFoundException, NoSuchFieldException, IllegalAccessException, InstantiationException, NoSuchMethodException, InvocationTargetException {
//获取类对象
Class<?> c1 = Class.forName("com.deu.javasm.day0310.Monkey");
//获取指定的成员变量
Field field = c1.getField("name");
//获取所有public修饰的成员变量(包括从父类继承的)
Field[] fields = c1.getFields();
//获取定的成员变量(不管什么权限修饰的)(不包含父类继承的)
Field declaredField = c1.getDeclaredField("name");
//获取所有public修饰的成员变量(不管什么权限修饰的)(不包含父类继承的)
Field[] declaredFields = c1.getDeclaredFields();
//创建对象
Constructor<?> declaredConstructor = c1.getDeclaredConstructor();
Object o = declaredConstructor.newInstance();
//赋值
declaredField.setAccessible(true);
declaredField.set(o, "houzi");
System.out.println(o);
}
5. 使用反射 操作方法 调用方法
public static void method6() throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
//获取类对象
Class<?> c1 = Class.forName("com.deu.javasm.day0310.Monkey");
//获取指定的方法 包括父类继承的
Method method = c1.getMethod("name",String.class);
//获取所有public修饰的方法 包括父类继承的
Method[] methods = c1.getMethods();
//获取指定的方法 (不管什么权限修饰符;不包含继承的)
Method name = c1.getDeclaredMethod("name", String.class);
//获取所有的方法 (不管什么权限修饰符;不包含继承的)
Method[] declaredMethods = c1.getDeclaredMethods();
//创建对象
Constructor<?> declaredConstructor = c1.getDeclaredConstructor();
Object o = declaredConstructor.newInstance();
//方法调用
name.setAccessible(true);
name.invoke(o,"houzi");
//有关静态方法的调用
Method name1 = c1.getDeclaredMethod("name", String.class);
name1.invoke(null,"houzi");
}
标签:反射,java,name,Class,获取,declaredConstructor,c1,public
From: https://www.cnblogs.com/jh0129/p/17204870.html