java--反射--课后作业&知识梳理

Posted 2021-06-30 张紫韩

1. 课后练习
   1. 

      1. package com.model.homework;
         
         import java.lang.reflect.Field;
         import java.lang.reflect.InvocationTargetException;
         import java.lang.reflect.Method;
         
         /**
          * @Description:测试类
          * @Author: 张紫韩
          * @Crete 2021/6/29 23:24
          */
         public class HomeWorkDemo01 {
             public static void main(String[] args) throws ClassNotFoundException, IllegalAccessException, InstantiationException,
          NoSuchMethodException, InvocationTargetException, NoSuchFieldException {
                 Class<?> aClass = Class.forName("com.model.homework.PrivateTest");
                 Object o = aClass.newInstance();
                 Field name = aClass.getDeclaredField("name");
                 name.setAccessible(true);
                 name.set(o, "张紫韩");
                 Method getName = aClass.getMethod("getName");
                 Object invoke = getName.invoke(o);
                 System.out.println(invoke);
             }
         
         }
         class PrivateTest{
             private String name="helloKitty";
         
             public String getName() {
                 return name;
             }
         }

   2. 

      1.  

         package com.model.homework;
         
         import java.io.File;
         import java.lang.reflect.Constructor;
         import java.lang.reflect.InvocationTargetException;
         import java.lang.reflect.Method;
         
         /**
          * @Description:测试类
          * @Author: 张紫韩
          * @Crete 2021/6/29 23:32
          */
         public class HomeWorkDemo02 {
             public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InstantiationException, InvocationTargetException {
         
                 String path="D:\\\\qq\\\\IDEA\\\\IdeaProjects\\\\java_mianshi\\\\mianshi_fanshe\\\\src\\\\main\\\\resources\\\\mynew.txt";
                 Class<?> aClass = Class.forName("java.io.File");
                 Constructor<?>[] declaredConstructors = aClass.getDeclaredConstructors();
                 for (Constructor<?> declaredConstructor : declaredConstructors) {
                     System.out.println(declaredConstructor);
                 }
                 Constructor<?> constructor = aClass.getDeclaredConstructor(String.class);
                 Object o = constructor.newInstance(path);
                 System.out.println(o.getClass()); //File类型的
                 Method createNewFile = aClass.getMethod("createNewFile");
                 createNewFile.invoke(o);
                 System.out.println("创建文件成功");
         
             }
         }