springboot 添加拦截器

前提

已经写好了一个controller

public class HelloController {

    @GetMapping("/hello")
    public Object hello(){
        return "hello world";
    }
}

1.在controller包中创建一个interceptor包

2.在interceptor包中创建一个UserTokenInterceptor.class 并去实现 HandlerInterceptor

package com.imooc.controller.interceptor;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

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

public class UserTokenInterceptor implements HandlerInterceptor {

    /**
     * 拦截请求，在访问controller调用之前
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        System.out.println("进入到拦截器，被拦截。。");

        /**
         * false:请求被拦截，被驳回，验证出现问题
         * true: 请求在经过验证效验以后，是OK的,是可以放行
         */
        return false;
    }

    /**
     * 请求访问controller之后，渲染视图之前
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    /**
     * 请求访问controller之后，渲染视图之后
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }
}

3.注册到容器里

package com.imooc.config;

import com.imooc.controller.interceptor.UserTokenInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    @Bean
    public UserTokenInterceptor userTokenInterceptor(){
        return new UserTokenInterceptor();
    }

    /**
     * 注册拦截器
     * @param registry
     */
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(userTokenInterceptor())
                .addPathPatterns("/hello");

        WebMvcConfigurer.super.addInterceptors(registry);
    }
}

4.请求/hello