springboot 编写拦截器限制接口后台登录（坑：注入，json返回问题，获取header问题）

1.编写拦截器（处理获取header问题 json问题）

package com.pgmsg.interceptor;

import com.pgmsg.pojo.BackendAdmin;
import com.pgmsg.service.backend.impl.AdminServiceImpl;
import com.pgmsg.util.ToolUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.time.Instant;
import java.util.HashMap;

@Configuration
public class LoginHandlerInterceptor implements HandlerInterceptor {

    @Autowired
    AdminServiceImpl adminService;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        
        if (HttpMethod.OPTIONS.toString().equals(request.getMethod())) {
            System.out.println("OPTIONS请求，放行");
            return true;
        }

       // PrintWriter writer = response.getWriter();
        String method = request.getRequestURI();
        String token = request.getHeader("X-Token");
        System.out.println(method + "->进入登录拦截");
        System.out.println(token);
        // /backend/admin/login
        if (!method.equals("/backend/admin/login")) {
            if (token == null) {
                HashMap map = new HashMap<>(){
                    {
                        put("status","0");
                        put("msg","请先登录");
                    }
                };
                ToolUtil.getJson(response,map);
                return false;
            } else {
                BackendAdmin admin = adminService.getAdminByToken(token);
                if (admin != null && admin.getTokenExpire() >= Instant.now().getEpochSecond()) {
                    return true;
                } else {
                    HashMap map = new HashMap<>(){
                        {
                            put("status","0");
                            put("msg","登陆超时");
                        }
                    };
                    ToolUtil.getJson(response,map);
                    return false;
                }
            }
        }
        return true;
    }
}

2.编写配置（解决注入问题 自定义拦截问题）

package com.pgmsg.config;

import com.pgmsg.interceptor.LoginHandlerInterceptor;
import org.jetbrains.annotations.NotNull;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
@Component
public class WebConfig extends WebMvcConfigurationSupport {

    String []excludes =  new String[]{"
    @Bean
    public LoginHandlerInterceptor setBean2(){
        System.out.println("注入了handler");
        return new LoginHandlerInterceptor();
    }

    @Override
    public void addInterceptors(@NotNull InterceptorRegistry registry) {

        registry.addInterceptor(setBean2())
                .addPathPatterns("/**").excludePathPatterns(excludes);
        //所有请求都被拦截包括静态资源
    }
}

工具类（生成json返回）

    public static void getJson(HttpServletResponse response, HashMap map) throws IOException {
        response.setCharacterEncoding("UTF-8");
        response.setContentType("application/json; charset=utf-8");
        PrintWriter out = null;
        JSonObject res1 = new JSonObject();
        for(Map.Entry entry : map.entrySet()){
            res1.put(entry.getKey(),entry.getValue());
        }
        out = response.getWriter();
        out.append(res1.toString());
    }