SpringBoot之Interceptor拦截器

王念博客

发布于 2019-07-25 17:57:08

1.4K0

发布于 2019-07-25 17:57:08

文章被收录于专栏：王念博客王念博客

前言：之前跨域有用过，拦截器是拦截通过SpringMvc的请求，中间进行一些逻辑校验，比如权限控制。类似于Servlet的Filter

自定义拦截器的话可以通过实现HandlerInterceptor 或者继承HandlerInterceptorAdapter来定义。

1. 继承HandlerInterceptorAdapter

package com.example;

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 Administrator on 2016/10/14.
 */
public class Demo1Interceptor extends HandlerInterceptorAdapter {
    /**
     * This implementation always returns {@code true}.
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("preHandle方法");
        return true;
    }

    /**
     * This implementation is empty.
     */
    @Override
    public void postHandle(
            HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
            throws Exception {
        System.out.println("postHandle方法");
    }

    /**
     * This implementation is empty.
     */
    @Override
    public void afterCompletion(
            HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        System.out.println("afterCompletion方法");
    }

    /**
     * This implementation is empty.
     */
    @Override
    public void afterConcurrentHandlingStarted(
            HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        System.out.println("afterConcurrentHandlingStarted方法");

    }

}

2.实现HandlerInterceptor

package com.example;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletResponse;

/**
 * Created by Administrator on 2016/10/14.
 */
public class DemoInterceptor implements HandlerInterceptor {

    /**
     * 在请求处理之前进行调用（Controller方法调用之前）
     *
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(javax.servlet.http.HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle方法执行");
        return true;
    }

    /**
     * 请求处理之后进行调用，但是在视图被渲染之前(Controller方法调用之后)
     *
     * @param request
     * @param response
     * @param handler
     * @param modelAndView
     * @throws Exception
     */
    @Override
    public void postHandle(javax.servlet.http.HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle方法执行");
    }

    /**
     * 在整个请求结束之后被调用，也就是在DispatcherServlet渲染了对应的视图之后执行
     *
     * @param request
     * @param response
     * @param handler
     * @param ex
     * @throws Exception
     */
    @Override
    public void afterCompletion(javax.servlet.http.HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion方法执行");
    }
}

3.在WebMvcConfigurerAdapter里添加拦截器

package com.example.config;

import com.example.DemoInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;


@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {

  
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new DemoInterceptor()).addPathPatterns("/**");
        registry.addInterceptor(new Demo1Interceptor());
    }


}

4.测试访问controller的时候进入拦截器

preHandle方法需要返回值，如果是false 则不往下执行。因为拦截器是SpringMvc的，必须DispatcherServlet请求的才能拦截到。

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