多態反射機制

package duotai;

class Customer{
    @SuppressWarnings("unused")
	private String account;
	@SuppressWarnings("unused")
	private String password;
	//有兩個函數名稱一樣，但是系統可以接受，這叫做函數重載（靜態多態性）
	//一個函數呈現爲多種狀態，系統能夠根據參數來決定調用誰
	//三種情況：參數個數不同，參數個數相同類型不同，個數類型相同出現的順序不同
	//靜態是指：雖然函數名只有一個，但是要寫代碼要寫多個
	public Customer()
	{
		System.out.println("構造函數1");
	}
	
	public Customer(String account, String password) {
		System.out.println("構造函數2");
		this.account=account;
		this.password=password;
	}
}


public class CustomerTest {
	public static void main(String[] args) {
		@SuppressWarnings("unused")
		Customer cus1 = new Customer();//調用構造函數
		@SuppressWarnings("unused")
		Customer cus2 = new Customer("3213","1213");//調用構造函數
	}

}

package duotai;

//模塊1調用一個對話框，讓對話框顯示出來

class Module1 {
	private Dialog dialog;

	public Module1(Dialog dialog) {
		this.dialog = dialog;
	}
	
	public void callDialog(){
		dialog.show();
	}

}

abstract class Dialog{
	public abstract void show();
}
class Dialog1 extends Dialog {
	public void show() {
		System.out.println("對話框1顯示");
	}
}
//客戶對Dialog1不滿意想自己開發一個Dialog2，被Module1調用，不能改變Module1原代碼

class Dialog2 extends Dialog{
	public void show() {
		System.out.println("對話框2顯示");
	}
}


public class DaliogTest {

	public static void main(String[] args) {
		
		Dialog1 dia = new Dialog1();
		Module1 mod1 = new Module1(dia);
		
		mod1.callDialog();
	}

}

package duotai;

//動態多態性一般在繼承時使用
abstract class Person{
	public abstract void printInfo();
}

class Student extends Person{
	public void printInfo() {
		System.out.println("學生打印");
	}
}

class Teacher extends Person{
	public void printInfo() {
		System.out.println("老師打印");
	}
}

public class StudentTest {
/*	public static void print(Student stu) {
		stu.printInfo();
	}

	public static void print(Teacher tea) {
		tea.printInfo();
	}*/
  public static void  print(Person p) {//父類的引用可以指向子類對象
	p.printInfo();
}
	public static void main(String[] args) {
		print(new Student()); 
	}

}

package fanshe;


public class Customer {
	private String account;
	private String password;

	public Customer() {
		System.out.println("構造函數1");
	}

	public Customer(String account, String password) {
		System.out.println("構造函數2");
		this.account = account;
		this.password = password;
	}

	public void printInfo() {
		System.out.println("賬號：" + account + "密碼" + password);
	}
}

package fanshe;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

public class Test1 {
	@SuppressWarnings("unchecked")
	public static void main(String[] args) throws Exception {

		String className = "fanshe.Customer";
		// className cus = new className();
		// 得到類的信息
		Class c = Class.forName(className);

		// 得到構造函數，就可以生成一個對象
		Constructor[] cons = c.getConstructors();
		for (int i = 0; i < cons.length; i++) {
			String str = cons[i].getName();
			System.out.println("名字：" + str);
			
			Class[] params = cons[i].getParameterTypes();// 得到參數類型
			for (int j = 0; j < params.length; j++) {
				String name = params[j].getName();
				System.out.println(name);
			}
		}
		//得到裏面的成員函數(包括繼承過來的)，就可以調用成員函數
		Method[] met = c.getMethods();
		for (int i = 0; i < met.length; i++) {
			String str = met[i].getName();
			System.out.println("名字：" + str);
			
			Class[] params = met[i].getParameterTypes();// 得到參數類型
			for (int j = 0; j < params.length; j++) {
				String name = params[j].getName();
				System.out.println(name);
			}
		}
	}

}

package fanshe;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;

public class Test2 {
	@SuppressWarnings("unchecked")
	public static void main(String[] args) throws Exception {
		/*
		 * 反射爲配置文件改變模塊行爲提供了可能
		 */
		String className = "fanshe.Customer";
		Class c = Class.forName(className);
		//c.newInstance();表示調用不帶參數的構造函數
		// 生成一個對象：用構造函數
		Constructor con1 = c.getConstructor(new Class[] {Class.forName("java.lang.String"),Class.forName("java.lang.String") });
		//Constructor con1 = c.getConstructor(new Class[] {});// 得到不帶參數的構造函數
	
		// 生成對象
		Object obj = con1.newInstance(new Object[] {"222","111"});
		//Object obj = con1.newInstance(new Object[] {});// 表示不傳入參數
		//怎樣調用obj裏面的方法
		Method met = c.getMethod("printInfo", new Class[]{});//得到方法
		met.invoke(obj, new Object[]{});//調用
		
		/*Customer cus = new Customer("222","111");
		cus.printInfo();*/
		
	}

}


/*public class Test2 {
	public static void main(String[] args) throws Exception {
		String className = "fanshe.Customer";
		Class c = Class.forName(className);
		Constructor con1 = c.getConstructor(new Class[] {Class.forName("java.lang.String"),Class.forName("java.lang.String") });
		Object obj = con1.newInstance(new Object[] {"222","111"});
		Method met = c.getMethod("printInfo", new Class[]{});
		met.invoke(obj, new Object[]{});
	}
}*/