Java語言程序設計課件：13課反射

1、Java中的 反射 reflect動態(tài)實例化(ch13.reflect.DynamicCreate)動態(tài)調(diào)用方法(ch13.reflect. DynamicDemo /ch13.reflect. DynamicDemo2)動態(tài)獲得屬性(ch13.reflect. DynamicField)動態(tài)實例化-方法1 (無參數(shù))public static void main(String args) try String className = java.lang.String; Object obj = createObject(className); System.out.println(obj.g

2、etClass().toString(); catch (Exception e) System.out.println(e.getMessage(); e.printStackTrace(); public static Object createObject(String className) throws ClassNotFoundException, InstantiationException, IllegalAccessException Class clazz = Class.forName(className); Object obj = clazz.newInstance()

3、; return obj;動態(tài)實例化-方法2 (無參數(shù))public static Object createObject2(String className) throws ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException Class clazz = Class.forName(className); Object

4、 obj = clazz.getConstructor(new Class0).newInstance(); return obj; 動態(tài)實例化-方法3 (有參數(shù))public static Object createObject3(String className) throws ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityEx

5、ception Class clazz = Class.forName(className); Class classes=new Class2; classes0=String.class; classes1=Integer.class; Object obj =clazz.getConstructor(classes).newInstance(tom,123); return obj; 方法3-延伸public static void main(String args) try String className=“ch11_reflect.Student“; String classNam

6、es=java.lang.String,java.lang.Integer; obj=createObject23(className,classNames,jack,123); System.out.println(Student)obj).getName(); catch (Exception e) System.out.println(e.getMessage(); e.printStackTrace(); 方法3-延伸public static Object createObject23(String className,String argsClassNames,Object. va

7、lues) throws ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException Class clazz = Class.forName(className); Class classes=new ClassargsClassNames.length; for(int i=0;iclasses.length;i+) cla

8、ssesi=Class.forName(argsClassNamesi); Object obj =clazz.getConstructor(classes).newInstance(values); return obj; 動態(tài)調(diào)用方法動態(tài)調(diào)用方法-1（無參數(shù)）public static void main(String args) Object obj=new Student(jack,123); try Object result=dynamicInvokeMethod(obj,getName); System.out.println(result); catch (Exception

9、e) System.out.println(e.getMessage(); e.printStackTrace(); public static Object dynamicInvokeMethod(Object obj,String methodName) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException Method method=obj.getClass().getMethod(method

10、Name); return method.invoke(obj);動態(tài)調(diào)用方法-2（有參數(shù)）public static void main(String args) Object obj=new Student(jack,123); try String argClassName=java.lang.String; /Object result=dynamicInvokeMethod(obj,“setName); dynamicInvokeMethod2(obj,setName,argClassName,tom); System.out.println(Student)obj).getName

11、(); catch (Exception e) System.out.println(e.getMessage(); e.printStackTrace(); 動態(tài)調(diào)用方法-2（有參數(shù)）public static Object dynamicInvokeMethod2(Object obj,String methodName,String argsClassNames,Object. values) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodEx

12、ception, SecurityException, ClassNotFoundException Class classes=new ClassargsClassNames.length; for(int i=0;iclasses.length;i+) classesi=Class.forName(argsClassNamesi); Method method=obj.getClass().getMethod(methodName,classes); return method.invoke(obj,values); 動態(tài)獲得屬性 public static void main(Strin

13、g args) Object obj = new StudentPublic(jack, 123); try dynamicField(obj, name, tom); System.out.println(StudentPublic) obj).name); catch (Exception e) System.out.println(e.getMessage(); e.printStackTrace(); 動態(tài)獲得屬性public static void dynamicField(Object obj, String fieldName, Object value) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, NoSuchMethodException, SecurityException, NoSuchFieldException Field field