Java反射創建實例

package com.wkcto.chapter08.demo02;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;

/**
 * 通過反射創建對象(創建實例)
 * 		newInstance()
 * 
 * @author 蛙課網
 *
 */
public class Test01 {

	public static void main(String[] args) throws InstantiationException, IllegalAccessException, NoSuchMethodException, SecurityException, IllegalArgumentException, InvocationTargetException {
		//1) 創建Class對象
		Class<?> class1 = Person.class;
		
		//2) 直接通過Class對象創建實例,會調用類的無參構造方法,如果沒有無參構造,則實例化異常
		Object obj1 = class1.newInstance();
		System.out.println( obj1 );  	//調用對象的toString()	
		
		//3)通過構造方法創建實例
		//3.1 反射構造方法Person(String, int, String)
		Constructor<?> constructor = class1.getConstructor(String.class, int.class, String.class);
		
		//3.2通過構造方法 創建實例, 調用newInstance()方法,傳遞構造方法的實參
		Object obj2 = constructor.newInstance("lisi", 18,"男");    //new Person("lisi", 18,"男")
		System.out.println( obj2 );
		
		
	}

}

package com.wkcto.chapter08.demo02;

public class Person {
	public String name;
	int age;
	private String gender;
	static String country = "中國";
	
	public Person() {
		System.out.println("Person類的無參構造方法");
	}

	public Person(String name, int age, String gender) {
		System.out.println("Person類的有三個參數的構造方法");
		this.name = name;
		this.age = age;
		this.gender = gender;
	}
	
	public void set(String name, int age, String gender) {
		this.name = name;
		this.age = age;
		this.gender = gender;
	}

	@Override
	public String toString() {
		return "Person [name=" + name + ", age=" + age + ", gender=" + gender + "]";
	}
		
}