一、編寫過濾器

package com.learn.mall.filter;


import com.learn.mall.common.Constant;
import com.learn.mall.model.pojo.User;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import javax.servlet.http.HttpSession;
 
import java.io.IOException;
import java.io.PrintWriter;

/**
 * 使用者登入許可權過濾器
 */

public class AdminFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
            
 
throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)servletRequest;
        HttpSession session = request.getSession();
        //判斷使用者是否登入
        User user = (User) session.getAttribute(Constant.USER);
        if(user == null){
            PrintWriter out 
 
= new HttpServletResponseWrapper((HttpServletResponse)servletResponse).getWriter();
            out.write("{\"status\":\"10007\",\"msg\":\"NEED_LOGIN\",\"data\":\"null\"}");
            out.flush();
            out.close();
            return ;
        }
        //判斷使用者是否是超級管理員
        if(user.getRole().equals(1)){
            PrintWriter out = new HttpServletResponseWrapper((HttpServletResponse)servletResponse).getWriter();
            out.write("{\"status\":\"10008\",\"msg\":\"NEED_ADMIN\",\"data\":\"null\"}");
            out.flush();
            out.close();
        }else{
            //管理員登入則放行，執行後面的操作
            filterChain.doFilter(servletRequest,servletResponse);
        }
    }

    @Override
    public void destroy() {

    }
}

二、編寫過濾器配置檔案

package com.learn.mall.config;

import com.learn.mall.filter.AdminFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 使用者登入許可權過濾器的配置
 */
@Configuration
public class AdminFilterConfig {
    @Bean
    public AdminFilter adminFilter(){
        return new AdminFilter();
    }

    @Bean(name = "adminFilterConf")
    public FilterRegistrationBean adminFilterConfig(){
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(adminFilter());
        filterRegistrationBean.addUrlPatterns("/admin/category/*");
        filterRegistrationBean.addUrlPatterns("/admin/product/*");
        filterRegistrationBean.addUrlPatterns("/admin/order/*");
        filterRegistrationBean.setName("adminFilterConf");
        return filterRegistrationBean;
    }
}