JAva反射----指定したクラスの属性と方法を取得する

Person.JAvaコードは次のとおりです.

package com.reflect.bean;

public class Person {

	private String name;
	
	private int age;
	
	public Person(){
		
	}
	
	public Person(int age){
		this.age = age;
	}
	
	public Person(String name){
		this.name = name;
	}
	
	public Person(String name,int age){
		this.name = name;
		this.age = age;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}
	
	@Override
	public String toString(){
		return "["+this.name+" "+this.age+"]";
	}
	
}

Test.JAvaコードは次のとおりです.

package com.reflect.test;

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

import com.reflect.bean.Person;

public class Test {

	public static void main(String[] args) {
		Class<?> demo = null;
		try{
			demo = Class.forName("com.reflect.bean.Person");
		}catch (Exception e) {
			e.printStackTrace();
		}
		Person person1 = null;
		Person person2 = null;
		Person person3 = null;
		Person person4 = null;
		Constructor<?> cons[] = demo.getConstructors();
		try{
			person1 = (Person)cons[3].newInstance();
			person2 = (Person)cons[1].newInstance("zhangsan");
			person3 = (Person)cons[0].newInstance(20);
			person4 = (Person)cons[2].newInstance("lisi",20);
		}catch (Exception e) {
			e.printStackTrace();
		}
		Field[] field = demo.getDeclaredFields();
		Method[] method = demo.getDeclaredMethods();
		System.out.println("method : "+method[0]);
		System.out.println("field : "+field[0]);
		System.out.println(person1);
		System.out.println(person2);
		System.out.println(person3);
		System.out.println(person4);
	}
}

実行結果は次のとおりです.

method : public java.lang.String com.reflect.bean.Person.toString()
field : private java.lang.String com.reflect.bean.Person.name
[null 0]
[zhangsan 0]
[null 20]
[lisi 20]