lambda-novice novice

Someday

Part of the article content comes from
https://gitee.com/zhongfucheng/Java3y#spring%E5%AE%B6%E6%97%8F
http://c.biancheng.net/view/4241.html

Note background

When I was learning AOP today, there was a hint in the code, which can be replaced with lambda, so I wrote an article to see the difference before and after lambda replacement

Code one

Before replacement

package com.mengma.cglib;

import com.mengma.dao.GoodsDao;
import com.mengma.jdk.MyAspect;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;

import java.lang.reflect.Method;
public class MyBeanFactory {
    
    
    public static GoodsDao getBean() {
    
    
        // 准备目标类
        final GoodsDao goodsDao = new GoodsDao();
        // 创建切面类实例
        final MyAspect myAspect = new MyAspect();
        // 生成代理类，CGLIB在运行时，生成指定对象的子类，增强
        Enhancer enhancer = new Enhancer();
        // 确定需要增强的类
        enhancer.setSuperclass(goodsDao.getClass());
        // 添加回调函数
        enhancer.setCallback(new MethodInterceptor() {
    
    
            // intercept 相当于 jdk invoke，前三个参数与 jdk invoke—致
            @Override
            public Object intercept(Object proxy, Method method, Object[] args,
                                    MethodProxy methodProxy) throws Throwable {
    
    
                myAspect.myBefore(); // 前增强
                Object obj = method.invoke(goodsDao, args); // 目标方法执行
                myAspect.myAfter(); // 后增强
                return obj;
            }
        });
        // 创建代理类
        GoodsDao goodsDaoProxy = (GoodsDao) enhancer.create();
        return goodsDaoProxy;
    }
}

After replacement

package com.mengma.cglib;

import com.mengma.dao.GoodsDao;
import com.mengma.jdk.MyAspect;
import org.springframework.cglib.proxy.Enhancer;
import org.springframework.cglib.proxy.MethodInterceptor;
import org.springframework.cglib.proxy.MethodProxy;

import java.lang.reflect.Method;
public class MyBeanFactory {
    
    
    public static GoodsDao getBean() {
    
    
        // 准备目标类
        final GoodsDao goodsDao = new GoodsDao();
        // 创建切面类实例
        final MyAspect myAspect = new MyAspect();
        // 生成代理类，CGLIB在运行时，生成指定对象的子类，增强
        Enhancer enhancer = new Enhancer();
        // 确定需要增强的类
        enhancer.setSuperclass(goodsDao.getClass());
        // 添加回调函数
        // intercept 相当于 jdk invoke，前三个参数与 jdk invoke—致
        enhancer.setCallback((MethodInterceptor) (proxy, method, args, methodProxy) -> {
    
    
            myAspect.myBefore(); // 前增强
            Object obj = method.invoke(goodsDao, args); // 目标方法执行
            myAspect.myAfter(); // 后增强
            return obj;
        });
        // 创建代理类
        GoodsDao goodsDaoProxy = (GoodsDao) enhancer.create();
        return goodsDaoProxy;
    }
}

Code two

Before replacement

package com.mengma.jdk;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import com.mengma.dao.CustomerDao;
import com.mengma.dao.CustomerDaoImpl;
public class MyBeanFactory {
    
    
    public static CustomerDao getBean() {
    
    
        // 准备目标类
        final CustomerDao customerDao = new CustomerDaoImpl();
        // 创建切面类实例
        final MyAspect myAspect = new MyAspect();
        // 使用代理类，进行增强
        return (CustomerDao) Proxy.newProxyInstance(
                MyBeanFactory.class.getClassLoader(),
                new Class[] {
    
     CustomerDao.class }, new InvocationHandler() {
    
    
                    public Object invoke(Object proxy, Method method,
                                         Object[] args) throws Throwable {
    
    
                        myAspect.myBefore(); // 前增强
                        Object obj = method.invoke(customerDao, args);
                        myAspect.myAfter(); // 后增强
                        return obj;
                    }
                });
    }
}

After replacement

package com.mengma.jdk;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import com.mengma.dao.CustomerDao;
import com.mengma.dao.CustomerDaoImpl;
public class MyBeanFactory {
    
    
    public static CustomerDao getBean() {
    
    
        // 准备目标类
        final CustomerDao customerDao = new CustomerDaoImpl();
        // 创建切面类实例
        final MyAspect myAspect = new MyAspect();
        // 使用代理类，进行增强
        return (CustomerDao) Proxy.newProxyInstance(
                MyBeanFactory.class.getClassLoader(),
                new Class[] {
    
     CustomerDao.class }, (proxy, method, args) -> {
    
    
                    myAspect.myBefore(); // 前增强
                    Object obj = method.invoke(customerDao, args);
                    myAspect.myAfter(); // 后增强
                    return obj;
                });
    }
}