import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.TypeVariable;public class Main {/*** 为了看清楚Java反射部分代码，所有异常我都最后抛出来给虚拟机处理！* @param args* @throws ClassNotFoundException* @throws InstantiationException* @throws IllegalAccessException* @throws InvocationTargetException * @throws IllegalArgumentException * @throws NoSuchFieldException * @throws SecurityException * @throws NoSuchMethodException */public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, SecurityException, NoSuchFieldException, NoSuchMethodException {// TODO Auto-generated method stub//Demo1.  通过Java反射机制得到类的包名和类名
        Demo1();System.out.println("===============================================");//Demo2.  验证所有的类都是Class类的实例对象
        Demo2();System.out.println("===============================================");//Demo3.  通过Java反射机制，用Class 创建类对象[这也就是反射存在的意义所在]，无参构造
        Demo3();System.out.println("===============================================");//Demo4:  通过Java反射机制得到一个类的构造函数，并实现构造带参实例对象
        Demo4();System.out.println("===============================================");//Demo5:  通过Java反射机制操作成员变量, set 和 get
        Demo5();System.out.println("===============================================");//Demo6: 通过Java反射机制得到类的一些属性： 继承的接口，父类，函数信息，成员信息，类型等
        Demo6();System.out.println("===============================================");//Demo7: 通过Java反射机制调用类中方法
        Demo7();System.out.println("===============================================");//Demo8: 通过Java反射机制获得类加载器
        Demo8();System.out.println("===============================================");}/*** Demo1: 通过Java反射机制得到类的包名和类名*/public static void Demo1(){Person person = new Person();System.out.println("Demo1: 包名: " + person.getClass().getPackage().getName() + "，" + "完整类名: " + person.getClass().getName());}/*** Demo2: 验证所有的类都是Class类的实例对象* @throws ClassNotFoundException */public static void Demo2() throws ClassNotFoundException{//定义两个类型都未知的Class , 设置初值为null, 看看如何给它们赋值成Person类Class<?> class1 = null;Class<?> class2 = null;//写法1, 可能抛出 ClassNotFoundException [多用这个写法]class1 = Class.forName("cn.lee.demo.Person");System.out.println("Demo2:(写法1) 包名: " + class1.getPackage().getName() + "，" + "完整类名: " + class1.getName());//写法2class2 = Person.class;System.out.println("Demo2:(写法2) 包名: " + class2.getPackage().getName() + "，" + "完整类名: " + class2.getName());}/*** Demo3: 通过Java反射机制，用Class 创建类对象[这也就是反射存在的意义所在]* @throws ClassNotFoundException * @throws IllegalAccessException * @throws InstantiationException */public static void Demo3() throws ClassNotFoundException, InstantiationException, IllegalAccessException{Class<?> class1 = null;class1 = Class.forName("cn.lee.demo.Person");//由于这里不能带参数，所以你要实例化的这个类Person，一定要有无参构造函数哈～Person person = (Person) class1.newInstance();person.setAge(20);person.setName("LeeFeng");System.out.println("Demo3: " + person.getName() + " : " + person.getAge());}/*** Demo4: 通过Java反射机制得到一个类的构造函数，并实现创建带参实例对象* @throws ClassNotFoundException * @throws InvocationTargetException * @throws IllegalAccessException * @throws InstantiationException * @throws IllegalArgumentException */public static void Demo4() throws ClassNotFoundException, IllegalArgumentException, InstantiationException, IllegalAccessException, InvocationTargetException{Class<?> class1 = null;Person person1 = null;Person person2 = null;class1 = Class.forName("cn.lee.demo.Person");//得到一系列构造函数集合Constructor<?>[] constructors = class1.getConstructors();person1 = (Person) constructors[0].newInstance();person1.setAge(30);person1.setName("leeFeng");person2 = (Person) constructors[1].newInstance(20,"leeFeng");System.out.println("Demo4: " + person1.getName() + " : " + person1.getAge()+ "  ,   " + person2.getName() + " : " + person2.getAge());}/*** Demo5: 通过Java反射机制操作成员变量, set 和 get* * @throws IllegalAccessException * @throws IllegalArgumentException * @throws NoSuchFieldException * @throws SecurityException * @throws InstantiationException * @throws ClassNotFoundException */public static void Demo5() throws IllegalArgumentException, IllegalAccessException, SecurityException, NoSuchFieldException, InstantiationException, ClassNotFoundException{Class<?> class1 = null;class1 = Class.forName("cn.lee.demo.Person");Object obj = class1.newInstance();Field personNameField = class1.getDeclaredField("name");personNameField.setAccessible(true);personNameField.set(obj, "胖虎先森");System.out.println("Demo5: 修改属性之后得到属性变量的值：" + personNameField.get(obj));}/*** Demo6: 通过Java反射机制得到类的一些属性： 继承的接口，父类，函数信息，成员信息，类型等* @throws ClassNotFoundException */public static void Demo6() throws ClassNotFoundException{Class<?> class1 = null;class1 = Class.forName("cn.lee.demo.SuperMan");//取得父类名称Class<?>  superClass = class1.getSuperclass();System.out.println("Demo6:  SuperMan类的父类名: " + superClass.getName());System.out.println("===============================================");Field[] fields = class1.getDeclaredFields();for (int i = 0; i < fields.length; i++) {System.out.println("类中的成员: " + fields[i]);}System.out.println("===============================================");//取得类方法Method[] methods = class1.getDeclaredMethods();for (int i = 0; i < methods.length; i++) {System.out.println("Demo6,取得SuperMan类的方法：");System.out.println("函数名：" + methods[i].getName());System.out.println("函数返回类型：" + methods[i].getReturnType());System.out.println("函数访问修饰符：" + Modifier.toString(methods[i].getModifiers()));System.out.println("函数代码写法： " + methods[i]);}System.out.println("===============================================");//取得类实现的接口,因为接口类也属于Class,所以得到接口中的方法也是一样的方法得到哈Class<?> interfaces[] = class1.getInterfaces();for (int i = 0; i < interfaces.length; i++) {System.out.println("实现的接口类名: " + interfaces[i].getName() );}}/*** Demo7: 通过Java反射机制调用类方法* @throws ClassNotFoundException * @throws NoSuchMethodException * @throws SecurityException * @throws InvocationTargetException * @throws IllegalAccessException * @throws IllegalArgumentException * @throws InstantiationException */public static void Demo7() throws ClassNotFoundException, SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException, InstantiationException{Class<?> class1 = null;class1 = Class.forName("cn.lee.demo.SuperMan");System.out.println("Demo7: \n调用无参方法fly()：");Method method = class1.getMethod("fly");method.invoke(class1.newInstance());System.out.println("调用有参方法walk(int m)：");method = class1.getMethod("walk",int.class);method.invoke(class1.newInstance(),100);}/*** Demo8: 通过Java反射机制得到类加载器信息* * 在java中有三种类类加载器。[这段资料网上截取]1）Bootstrap ClassLoader 此加载器采用c++编写，一般开发中很少见。2）Extension ClassLoader 用来进行扩展类的加载，一般对应的是jre\lib\ext目录中的类3）AppClassLoader 加载classpath指定的类，是最常用的加载器。同时也是java中默认的加载器。* * @throws ClassNotFoundException */public static void Demo8() throws ClassNotFoundException{Class<?> class1 = null;class1 = Class.forName("cn.lee.demo.SuperMan");String nameString = class1.getClassLoader().getClass().getName();System.out.println("Demo8: 类加载器类名: " + nameString);}}
/*** * @author xiaoyaomeng**/
class  Person{private int age;private String name;public Person(){}public Person(int age, String name){this.age = age;this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}
}class SuperMan extends Person implements ActionInterface
{private boolean BlueBriefs;public void fly(){System.out.println("超人会飞耶～～");}public boolean isBlueBriefs() {return BlueBriefs;}public void setBlueBriefs(boolean blueBriefs) {BlueBriefs = blueBriefs;}@Overridepublic void walk(int m) {// TODO Auto-generated method stubSystem.out.println("超人会走耶～～走了" + m + "米就走不动了！");}
}
interface ActionInterface{public void walk(int m);
}