Class对象功能概述和Class对象功能获取Field

Constructor[] getConstructors()

Constructor getConstructor(类... parameterTypes)

Constructor getDeclareConstructor(类... paramterTypes)

Constructor[] getDeclaredConstructors()获取所有的成员变量不考虑修饰符

Constructor:构造方法

创建对象

T newUnstance(Object... initargs)

如果使用空参数构造方法创建对象，操作可以简化：Class对象的newInstance方法

package com.yang.reflect;

import com.yang.exercises.Person;

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

public class ReflectStudy02 {

    public static void main(String[] args) throws Exception {
        /**
         * 2.获取构造方法们
         * Constructor[] getConstructors()
         * Constructor getConstructor(类... parameterTypes)
         *
         * Constructor getDeclareConstructor(类... paramterTypes)
         * Constructor[] getDeclaredConstructors()获取所有的成员变量不考虑修饰符
         */
        Class<Person> personClass = Person.class;
        //Constructor getConstructor(类... parameterTypes)
        Constructor<Person> constructor = personClass.getConstructor(String.class, int.class);
        System.out.println(constructor);

        //创建对象
        Person p = constructor.newInstance("张三", 18);
        System.out.println(p);

        Person person = personClass.newInstance();
        System.out.println(person);

    }
}

Class对象功能获取Field

package com.yang.reflect;

import com.yang.exercises.Person;

import java.lang.reflect.Method;

public class ReflectStudy03 {
    public static void main(String[] args) throws Exception {
        /**
         3.获取成员方法们
         Method[] getMethod()
         Method getMethod(String name,类<?>... paramterTypes)
         Method[] getDeclaredMethods()
         Method getDeclaredMethod(String name,类<?>... paramterTypes)
         */
        //获取Person的class对象
        Class<Person> personClass = Person.class;
        //获取指定名称的方法
        Method eat = personClass.getMethod("eat");
        Person p = new Person();
        //执行方法
        eat.invoke(p);

        Method eat2 = personClass.getMethod("eat",String.class);
        //执行方法
        eat2.invoke(p,"饭");

        //获取所有public修饰的方法
        Method[] methods = personClass.getMethods();
        for (Method method : methods) {
            System.out.println(method);
            String name = method.getName();
            System.out.println(name);
        }

        //获取类名
        String className = personClass.getName();
        System.out.println(className);

    }
}