Java基础巩固——反射

public class TestGetField extends Object {
    private static final long serialVersionUID = -2862585049955236662L;

    public static void main(String args[]) throws Exception {
        Class<?> clazz = Class.forName("reflect.TestGetField");
        System.out.println("===============本类属性===============");
        // 取得本类属性
        Field[] fields = clazz.getDeclaredFields();
        getField(fields);


        System.out.println("==========实现的接口或者父类的属性==========");
        // 取得实现的接口或者父类的属性
        Field[] fatherField = clazz.getFields();
        getField(fatherField);
    }

    public static void getField(Field[] fields) {
        for (Field field : fields) {
            // 权限修饰符
            int mo = field.getModifiers();
            String priv = Modifier.toString(mo);
            Class<?> type = field.getType();
            System.out.println(priv + " " + type.getName() + " " + field.getName() + ";");
        }
    }
}

public class TestGetMethod implements Serializable{
    private static final String  testString= "hello";
    public static void main(String args[]) throws Exception{
        Class<?> clazz = Class.forName("reflect.TestGetMethod");
        Method[] methods = clazz.getMethods();
        for (Method method :methods){
            Class<?> returnType = method.getReturnType();
            Class<?> para[] = method.getParameterTypes();
            int temp = method.getModifiers();
            System.out.print(Modifier.toString(temp));
            System.out.print(returnType.getName());
            System.out.print(method.getName());

            for (Class par:para){
                System.out.println(par.getName());
            }
            
        }
    }
}

public class TestNewInstance {
    public static void main(String[] args) throws Exception{
        Class<?> class1 = null;
        class1 = Class.forName("reflect.User");
        // 第一种方法，实例化默认构造方法，调用set赋值
        User user = (User)class1.newInstance();
        user.setAge(20);
        user.setName("adf");
        System.out.println(user);
        // 第二种 取得全部的构造函数 使用构造函数赋值

    }
}

class User {
    private int age;
    private String name;
    public User() {
        super();
    }
    public User(String name) {
        super();
        this.name = name;
    }
    public User(int age, String name) {
        super();
        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;
    }
    @Override
    public String toString() {
        return "User [age=" + age + ", name=" + name + "]";
    }
}

public class TestUseMethod {
    public static void main(String[] args)throws Exception{
        Class<?> clazz = Class.forName("reflect.TestUseMethod");
        // 调用reflect1方法
        Method method = clazz.getMethod("reflect1");
        method.invoke(clazz.newInstance());

        // 调用reflect2方法
        method = clazz.getMethod("reflect2", int.class, String.class);
        method.invoke(clazz.newInstance(),20,"test");
    }

    public void reflect1() {
        System.out.println("Java 反射机制 - 调用某个类的方法1.");
    }
    public void reflect2(int age, String name) {
        System.out.println("Java 反射机制 - 调用某个类的方法2.");
        System.out.println("age -> " + age + ". name -> " + name);
    }
}

public class TestProxy {
    public static void main(String args[]) throws Exception{
        MyInvocationHandler demo = new MyInvocationHandler();
        Subject subject = (Subject) demo.bind(new RealSubject());
        System.out.println(subject.say("janti",20));
    }
}

interface Subject{
    public String say(String name, int age);
}

// 定义真实项目
class RealSubject implements Subject {
    public String say(String name, int age) {
        return name + "  " + age;
    }
}

//如果想要完成动态代理，首先需要定义一个InvocationHandler接口的子类，已完成代理的具体操作。

class MyInvocationHandler implements InvocationHandler{

    private Object object = null;
    public Object bind(Object obj){
        this.object = obj;
        return Proxy.newProxyInstance(obj.getClass().getClassLoader(),obj.getClass().getInterfaces(),this);
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object temp = method.invoke(this.object,args);
        return temp;
    }
}