使用拦截器处理公共逻辑

定义拦截器

定义一个类去实现HandlerInterceptor接口，在这个接口中有三个方法

default boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
 //这个preHandle方法是在执行Handler之前(执行业务逻辑之前)
    return true;
}

default void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {
//在执行Handler成功(执行业务逻辑成功之后)
}

default void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {
//在请求处理完毕之后执行
}

package com.atguigu.spzx.manager.interceptor;

import com.alibaba.fastjson.JSON;
import com.atguigu.spzx.model.entity.system.SysUser;
import com.atguigu.spzx.model.entity.system.SysUserThreadLocalAuthContextUtil;
import com.atguigu.spzx.utils.ljxAssertUtil;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
@Component
public class LoginInterceptor implements HandlerInterceptor {
    @Autowired
    RedisTemplate<String,String> redisTemplate;
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("使用拦截器");
        //处理OPTIONS
        if (request.getMethod().equals("OPTIONS")){
            return true;
        }
        //获取token
        String token=request.getHeader("token");
        //从redis中获取到SysUser

        String json=redisTemplate.opsForValue().get("user:login:"+token);
        ljxAssertUtil.notNull(json,"缓存中没有token");
        SysUser sysUser=  JSON.parseObject(json,SysUser.class);
        //存储到本地线程当中
        SysUserThreadLocalAuthContextUtil.set(sysUser);
        return true;
    }
}

这个案例是把公共的将token从redis中拿出用户信息的逻辑、并将用户信息存储到本地线程当中封装成一个拦截器。

注册拦截器 

package com.atguigu.spzx.manager.config;

import com.atguigu.spzx.manager.interceptor.LoginInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Component
public class WebMvcConfiguration implements WebMvcConfigurer {
    @Autowired
    LoginInterceptor loginInterceptor;
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor)
                .excludePathPatterns("/admin/system/index/login","/admin/system/index/generateValidateCode")
                .addPathPatterns("/**");
    }
}

定义一个类实现WebMvcConfigurer ，并在此添加拦截器相关的信息。