性能对比分析

结果

package com.guo.reflection;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

//分析性能问题
public class Test10 {
    public static void main(String[] args) throws ClassNotFoundException, InvocationTargetException, InstantiationException, IllegalAccessException, NoSuchMethodException {
        test01();
        test02();
        test03();

    }

    //1.普通方式调用
    public static void test01(){
        User user = new User();

        long startTime  = System.currentTimeMillis();

        for (int i = 0; i < 1000000000; i++) {
            user.getName();
        }

        long endTime  = System.currentTimeMillis();

        System.out.println("普通方法执行10亿次需要"+(endTime-startTime)+"ms");
    }


    //2.反射方式调用
    public static void test02() throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {

        Class c1 = Class.forName("com.guo.reflection.User");
        User user1 =(User) c1.newInstance();

        Method getName = c1.getDeclaredMethod("getName", null);

        long startTime  = System.currentTimeMillis();

        for (int i = 0; i < 1000000000; i++) {
            getName.invoke(user1,null);
        }

        long endTime  = System.currentTimeMillis();

        System.out.println("反射方式执行10亿次需要"+(endTime-startTime)+"ms");
    }


    //3.反射方式调用,关闭检测
    public static void test03() throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {

        Class c2 = Class.forName("com.guo.reflection.User");
        User user2 =(User) c2.newInstance();

        Method getName = c2.getDeclaredMethod("getName", null);

        getName.setAccessible(true);

        long startTime  = System.currentTimeMillis();

        for (int i = 0; i < 1000000000; i++) {
            getName.invoke(user2,null);
        }

        long endTime  = System.currentTimeMillis();

        System.out.println("关闭检测执行10亿次需要"+(endTime-startTime)+"ms");
    }





}