spring boot 添加拦截器的简单实例

spring中拦截器主要分两种，一个是HandlerInterceptor，一个是MethodInterceptor

一、HandlerInterceptor

HandlerInterceptor是springMVC项目中的拦截器，它拦截的目标是请求的地址，比MethodInterceptor先执行。

1、创建我们自己的拦截器类并实现 HandlerInterceptor 接口或继承HandlerInterceptorAdapter。
2、创建一个Java类继承WebMvcConfigurerAdapter，并重写 addInterceptors 方法。
3、实例化我们自定义的拦截器，然后将对像手动添加到拦截器链中（在addInterceptors方法中添加）。

package com.qicheshetuan.backend.web.interceptor;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Created by 15117 on 2018/4/27.
 */
public class TestInterceptor extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("在控制器执行前调用 ");
        Boolean flag = true;
        if(flag){
            System.out.println(request.getMethod());
            return true;
        }else{
            System.out.println(request.getMethod());
            return false;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("在后端控制器执行后调用 ");
        super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("整个请求执行完成后调用 ");
        super.afterCompletion(request, response, handler, ex);
    }
}

package com.qicheshetuan.backend.web.interceptor;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

/**
 * Created by 15117 on 2018/4/27.
 */
@Configuration
public class InterceptorConfig extends WebMvcConfigurerAdapter {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new TestInterceptor()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
}

二、MethodInterceptor

MethodInterceptor是AOP项目中的拦截器，它拦截的目标是方法，即使不是controller中的方法。实现MethodInterceptor拦截器大致也分为两种，一种是实现MethodInterceptor接口，另一种利用AspectJ的注解或配置。

基于注解的AspectJ方式

package com.qicheshetuan.backend.web.interceptor;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.springframework.stereotype.Component;

/**
 * Created by 15117 on 2018/4/27.
 */
@Component
@Aspect
public class AspectJInterceptor {

    @Around("execution(* com.qicheshetuan.backend.web.controller.AutoCommunityController.*(..))")
    public Object around(ProceedingJoinPoint pjp) throws Throwable {
        System.out.println("方法执行前");
        Object proceed = pjp.proceed();
        System.out.println("方法执行后");
        return proceed;
    }
}

package com.qicheshetuan.backend.web.interceptor;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

/**
 * Created by 15117 on 2018/4/27.
 */
@Component
@Aspect
public class AspectJInterceptor {

    @Pointcut("execution(* com.qicheshetuan.backend.web.controller..*.*(..))")
    public void execMethod(){

    }
    @Before("execMethod()")
    public void beforeMethod(JoinPoint joinPoint){
        System.out.println("方法前执行");
        System.out.println(joinPoint.getSignature().getName());
    }
}