java | 性能检测与提高

简单的检测和提高。

package com.redisc;

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

class Person {
    public String getName() {
        return name;
    }

public String getName2() {
        return name2;
    }

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

public String name;
    private String name2;

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

public Person() {
    }
}


public class Test {


    public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException, NoSuchMethodException, IllegalAccessException, InvocationTargetException, InstantiationException {
        // 普通方法调用
        Person person = new Person();
        long statrTime = System.currentTimeMillis();
        for (int i = 0; i < 1000000000; i++) {
            person.getName();
        }
        long endTime = System.currentTimeMillis();
        System.out.println(endTime - statrTime);

// 反射方法调用

Person person2 = new Person();
        Class c1 = person2.getClass();
        Method getName = c1.getDeclaredMethod("getName", null);
        long statrTime2 = System.currentTimeMillis();
        for (int i = 0; i < 1000000000; i++) {
            getName.invoke(person2, null);
        }
        long endTime2 = System.currentTimeMillis();
        System.out.println(endTime2 - statrTime2);


        // 反射方法验证关闭
        // 反射方法调用
        Person person3 = new Person();
        Class c3 = person3.getClass();
        Method getName3 = c3.getDeclaredMethod("getName", null);
        getName3.setAccessible(true);
        long statrTime3 = System.currentTimeMillis();
        for (int i = 0; i < 1000000000; i++) {
            getName3.invoke(person3, null);
        }
        long endTime3 = System.currentTimeMillis();
        System.out.println(endTime3 - statrTime3);

}
}

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