<!--java 反射工具包 -->
<!-- https://mvnrepository.com/artifact/com.esotericsoftware/reflectasm -->
<dependency>
    <groupId>com.esotericsoftware</groupId>
    <artifactId>reflectasm</artifactId>
    <version>1.11.3</version>
</dependency>

Test1:

public class Test1 {
    private int i ;
    private int num ;

    public Test1() {
    }

    public int getI() {
        return i;
    }

    public void setI(int i) {
        this.i = i;
    }

    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }
}

Test2:

import com.esotericsoftware.reflectasm.MethodAccess;

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

public class Test2 {

    public static void main(String[] args) throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        long now;
        long sum = 0;
        Test1 t = new Test1();

        now = System.currentTimeMillis();

        for(int i = 0; i<500000000; ++i){
            t.setNum(i);
            sum += t.getNum();
        }

        System.out.println("get-set耗时"+(System.currentTimeMillis() - now) + "ms秒，和是" +sum);

        sum = 0;
        now = System.currentTimeMillis();

        for(int i = 0; i<5000000; ++i){
            Class<?> c = Class.forName("Test1");
            Class<?>[] argsType = new Class[1];
            argsType[0] = int.class;
            Method m = c.getMethod("setNum", argsType);
            m.invoke(t, i);
            sum += t.getNum();
        }
        System.out.println("标准反射耗时"+(System.currentTimeMillis() - now) + "ms，和是" +sum);

        sum = 0;

        Class<?> c = Class.forName("Test1");
        Class<?>[] argsType = new Class[1];
        argsType[0] = int.class;
        Method m = c.getMethod("setNum", argsType);

        now = System.currentTimeMillis();

        for(int i = 0; i<500000000; ++i){
            m.invoke(t, i);
            sum += t.getNum();
        }
        System.out.println("缓存反射耗时"+(System.currentTimeMillis() - now) + "ms，和是" +sum);

        sum = 0;
        MethodAccess ma = MethodAccess.get(Test1.class);
        int index = ma.getIndex("setNum");
        now = System.currentTimeMillis();

        for(int i = 0; i<500000000; ++i){
            ma.invoke(t, index, i);
            sum += t.getNum();
        }
        System.out.println("reflectasm反射耗时"+(System.currentTimeMillis() - now) + "ms，和是" +sum);
    }
}

耗时：