性能对比分析（普通方法/反射/反射关闭检测）

性能对比分析（普通方法/反射/反射关闭检测）

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

//分析性能问题
public class Test10 {

    //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："+(endTime-startTime)+"ms"); //3ms
    }

    //反射方式调用
    public static void test02() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        User user = new User();
        Class c1 = user.getClass();

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

        long startTime = System.currentTimeMillis();

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

        long endTime = System.currentTimeMillis();

        System.out.println("反射方法执行10亿次："+(endTime-startTime)+"ms"); //3029ms
    }

    //反射方式调用   关闭检测
    public static void test03() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        User user = new User();
        Class c1 = user.getClass();

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

        long startTime = System.currentTimeMillis();

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

        long endTime = System.currentTimeMillis();

        System.out.println("关闭检测执行10亿次："+(endTime-startTime)+"ms"); //1389ms
    }

    public static void main(String[] args) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException {
        test01();
        test02();
        test03();
    }

}