【通过反射获取无参构造方法并使用】

package test;

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

/**
 * @author shusheng
 * @description 通过反射获取无参构造方法并使用
 * @Email shusheng@yiji.com
 * @date 2018/12/23 23:49
 */
public class ReflectDemo1 {

    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
        // 获取字节码文件对象
        Class c = Class.forName("test.Person");

        // 获取构造方法
        // public Constructor[] getConstructors():所有公共构造方法
        // public Constructor[] getDeclaredConstructors():所有构造方法
        Constructor[] cons = c.getDeclaredConstructors();
        for (Constructor con : cons) {
            System.out.println(con);
        }

        // 获取单个构造方法
        // public Constructor<T> getConstructor(Class<?>... parameterTypes)
        // 参数表示的是：你要获取的构造方法的构造参数个数及数据类型的class字节码文件对象
        Constructor con = c.getConstructor();

        // Person p = new Person();
        // System.out.println(p);
        // public T newInstance(Object... initargs)
        // 使用此 Constructor 对象表示的构造方法来创建该构造方法的声明类的新实例，并用指定的初始化参数初始化该实例。
        Object obj = con.newInstance();
        System.out.println(obj);

         Person p = (Person)obj;
         p.show();
    }

}

package test;

/**
 * @author shusheng
 * @description
 * @Email shusheng@yiji.com
 * @date 2018/12/23 23:49
 */
public class Person {
    private String name;
    int age;
    public String address;

    public Person() {
    }

    private Person(String name) {
        this.name = name;
    }

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

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

    public void show() {
        System.out.println("show");
    }

    public void method(String s) {
        System.out.println("method " + s);
    }

    public String getString(String s, int i) {
        return s + "---" + i;
    }

    private void function() {
        System.out.println("function");
    }

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

}