Spring boot 拦截器笔记

1. 实现 HandlerInterceptor 接口

package com.xunqi.gulimall.order.interceptor;

import com.xunqi.common.vo.MemberResponseVo;
import org.springframework.stereotype.Component;
import org.springframework.util.AntPathMatcher;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.PrintWriter;

import static com.xunqi.common.constant.AuthServerConstant.LOGIN_USER;

/**
 * @Description: 登录拦截器
 * @Created: with IntelliJ IDEA.
 * @author: LY
 * @createTime: 2020-07-02 18:37
 **/

@Component
public class LoginUserInterceptor implements HandlerInterceptor {
    
    

    //https://www.cnblogs.com/fsmly/p/11020641.html
    public static ThreadLocal<MemberResponseVo> loginUser = new ThreadLocal<>();

    //在请求到达之前进行拦截
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    
    

        String uri = request.getRequestURI();
        AntPathMatcher antPathMatcher = new AntPathMatcher();
        boolean match = antPathMatcher.match("/order/order/status/**", uri);
        boolean match1 = antPathMatcher.match("/payed/notify", uri);
        if (match || match1) {
    
    
            return true;
        }

        //获取登录的用户信息
        MemberResponseVo attribute = (MemberResponseVo) request.getSession().getAttribute(LOGIN_USER);

        if (attribute != null) {
    
    
            //把登录后用户的信息放在ThreadLocal里面进行保存
            loginUser.set(attribute);

            return true;
        } else {
    
    
            //未登录，返回登录页面
            response.setContentType("text/html;charset=UTF-8");
            PrintWriter out = response.getWriter();
            out.println("<script>alert('请先进行登录，再进行后续操作！');location.href='http://auth.gulimall.com/login.html'</script>");
            // session.setAttribute("msg", "请先进行登录");
            // response.sendRedirect("http://auth.gulimall.com/login.html");
            return false;
        }
    }

    //等待 preHandle 返回true 之后进行调用，且在视图渲染之前被调用
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
    
    

    }
    //等待 preHandle 返回true 之后进行调用，且在视图渲染之后被调用
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
    
    

    }
}

• preHandle

调用时间：Controller方法处理之前

执行顺序：链式Intercepter情况下，Intercepter按照声明的顺序一个接一个执行

若返回false，则中断执行，注意：不会进入afterCompletion

• postHandle

调用前提：preHandle返回true

调用时间：Controller方法处理完之后，DispatcherServlet进行视图的渲染之前，也就是说在这个方法中你可以对ModelAndView进行操作

执行顺序：链式Intercepter情况下，Intercepter按照声明的顺序倒着执行。

备注：postHandle虽然post打头，但post、get方法都能处理

• afterCompletion

调用前提：preHandle返回true

调用时间：DispatcherServlet进行视图的渲染之后

多用于清理资源

2.配置文件中配置拦截器(实现 WebMvcConfigurer )

package com.xunqi.gulimall.order.config;

import com.xunqi.gulimall.order.interceptor.LoginUserInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @Description:
 * @Created: with IntelliJ IDEA.
 * @author: LY
 * @createTime: 2020-07-02 18:38
 **/

@Configuration
public class OrderWebConfig implements WebMvcConfigurer {

    @Autowired
    private LoginUserInterceptor loginUserInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //添加拦截路径
        registry.addInterceptor(loginUserInterceptor).addPathPatterns("/**");
    }
}

3.业务代码中使用

//获取当前用户登录的信息
MemberResponseVo memberResponseVo = LoginUserInterceptor.loginUser.get();