浅谈AOP

AOP是一种编程范式，与语言无关，是一种编程思想。

面向切面（AOP）Aspect Oriented Programming
面向对象（OOP）Object Oriented Programming
面向过程（POP）Procedure Oriented Programming

面向过程与面向对象的区别：（换了个角度看世界，换了个姿势处理问题）

面相对象是垂直划分为不同的，并且相对独立的。封装成类，并且有自己的行为。
面相切面是一种横切的技术，将面向对象构成的体系进行水平切割；
并且把可能会影响到的多个类的公共行为封装成可重用的模块，这个模块称为（切面）。

核心思想：将通用逻辑从业务中分离出来

@Aspect //切面
@Component //组件引入Spring容器中

//切点
@Pointcut(“execution(public * com.hsw.controller.GirlController.*(..))”)
//execution()执行括号里面的方法进行拦截任意返回值，任意方法，任意参数

@Before()
@After()

package com.hsw.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.*;
import org.hibernate.boot.jaxb.SourceType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.awt.*;

/**
 * ArvinWoo
 *
 * 设置切面 切点提取
 */
@Aspect
@Component //引入Spring容器中
public class HttpAspect {

    private final static Logger logger = LoggerFactory.getLogger(HttpAspect.class);

    //execution()执行括号里面的方法进行拦截 任意返回值，任意方法，任意参数
    @Pointcut("execution(public * com.hsw.controller.GirlController.*(..))")
    public void log(){
    }

    @Before("log()")
    public void doBefore(JoinPoint joinPoint){//JoinPoint 获取请求方法信息
        //HttpServletRequest 从 RequestContextHolder取得
        ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletRequest request = attributes.getRequest();

//        url  会把request请求变量放到url={}里面
        logger.info("url={}",request.getRequestURL());

//        method
        logger.info("method={}",request.getMethod());
//        ip
        logger.info("ip={}",request.getRemoteAddr());

//        类方法
        logger.info("class_method={}",joinPoint.getSignature().getDeclaringTypeName()+"."+joinPoint.getSignature().getName());

        //参数
        logger.info("args={}",joinPoint.getArgs());
    }

    @After("log()")
    public void doAfter(){
        logger.info("···");
    }

    //获取返回的内容
    @AfterReturning(returning = "object", pointcut = "log()")
    public void doAfterRetruning(Object object){
        logger.info("response={}",object.toString());
    }


}

遇到的错误

{
    "timestamp": 1510495946064,
    "status": 500,
    "error": "Internal Server Error",
    "exception": "org.springframework.http.converter.HttpMessageNotWritableException",
    "message": "Could not write JSON: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS); nested exception is com.fasterxml.jackson.databind.JsonMappingException: No serializer found for class org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS) (through reference chain: com.hsw.domain.Girl_$$_jvst83b_0[\"handler\"])",
    "path": "/girls/13"
}

根据提示，大致的意思应该是实体类在转化为json时，有属性值是null所致。

解决方法
在实体类上面加入：

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties({"handler","hibernateLazyInitializer" })

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