package com.xing.springbootinterceptor.interceptor;

import com.xing.springbootinterceptor.model.User;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//自定義的攔截器 只有繼承了HandlerInterceptor 自定義的類才算是一個(gè)攔截器
public class UserInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //編寫(xiě)攔截的規(guī)則
        //判斷用戶是否登錄 從session中取值
        User user=(User) request.getSession().getAttribute("user");
        if(user==null){
            //未登錄
            response.sendRedirect(request.getContextPath()+"/user/error");//重定向
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

package com.xing.springbootinterceptor.config;
import com.xing.springbootinterceptor.interceptor.UserInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

//表明這是一個(gè)配置類 即相當(dāng)于之前的xml配置文件
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {
    //這個(gè)配置類主要用來(lái)添加攔截請(qǐng)求
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        String[] addPathPatterns={
                "/user/**"
        };//設(shè)置攔截的路徑 不設(shè)置將會(huì)攔截所有的請(qǐng)求
        String[] excludePathPatterns={
                "/user/out",
                "/user/error",
                "/user/login"
        };//要排除的路徑 排除的路徑說(shuō)明不需要用戶登錄也可以訪問(wèn)
        //InterceptorRegistry 攔截器注冊(cè)類
        registry.addInterceptor(new UserInterceptor()).addPathPatterns(addPathPatterns).excludePathPatterns(excludePathPatterns);
//        WebMvcConfigurer.super.addInterceptors(registry);
    }
}

package com.xing.springbootinterceptor.controller;
import com.xing.springbootinterceptor.model.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
@RestController //該注解相當(dāng)于@Controller+@ResponseBody
@RequestMapping("/user")
public class UserController {
    @RequestMapping("/login")
    public String login(HttpServletRequest request){
    //這里只是模擬登錄 一旦輸入該請(qǐng)求 則表示登錄成功 便我往session中存值
        User user = new User();
        user.setId(1001);
        user.setUsername("張三");
        //將用戶的信息存放到session中
        request.getSession().setAttribute("user",user);
        return "login success";
    }
    //該請(qǐng)求需要用戶登錄之后才可訪問(wèn)
    @RequestMapping("/center")
    public String center(){
        return "See Center Message";
    }
    //該請(qǐng)求不登錄也可以訪問(wèn)
    @RequestMapping("/out")
    public String out(){
        return "Out See anytime";
    }
    //如果用戶未登錄訪問(wèn)了需要登錄的請(qǐng)求 便會(huì)自動(dòng)跳轉(zhuǎn)到該路徑
    @RequestMapping("/error")
    public String error(){
        return "error";
    }
}