Java反射之性能对比分析

示例:

package annoAndRe.reflection;

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

public class Test08 {
    
    
    //普通方法调用1亿次
    public static void test01() {
    
    
        People people = new People();
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < 100000000; i++) {
    
    
            people.getName();
        }
        long endTime = System.currentTimeMillis();
        System.out.println("普通方法调用10亿次需要: " + (endTime - startTime) + "ms");
    }

    // 反射方式调用
    public static void test02() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
    
    
        People people = new People();
        Class c1 = people.getClass();
        Method getName = c1.getDeclaredMethod("getName", null);
        long startTime = System.currentTimeMillis();
        for (int i = 0; i < 100000000; i++) {
    
    
            getName.invoke(people, null);
        }
        long endTime = System.currentTimeMillis();
        System.out.println("反射方式调用10亿次需要: " + (endTime - startTime) + "ms");
    }

    // 反射方式调用 关闭监测
    public static void test03() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
    
    
        People people = new People();
        Class c1 = people.getClass();
        Method getName = c1.getDeclaredMethod("getName", null);
        long startTime = System.currentTimeMillis();
        getName.setAccessible(true);
        for (int i = 0; i < 100000000; i++) {
    
    
            getName.invoke(people, null);
        }
        long endTime = System.currentTimeMillis();
        System.out.println("反射方式调用 关闭监测10亿次需要:" + (endTime - startTime) + " ms ");
    }

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

class People {
    
    
    private String name;

    public People() {
    
    
    }

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

    public String getName() {
    
    
        return name;
    }
}

运行结果: