拦截器实现Token校验 + ThreadLocal

拦截器实现Token校验 + ThreadLocal

一、学习目标

• 创建拦截器，对除登录注册外的接口进行token校验。
• 使用ThreadLocal存储当前用户ID。

二、核心知识点

• HandlerInterceptor：Spring MVC拦截器接口。
• ThreadLocal：线程局部变量，每个线程独立存储。
• token校验：从请求头获取token，解析验证，若无效返回401。

三、操作步骤

1. 创建UserContext

• 右键util文件夹，新建java类：UserContext

• UserContext中的代码如下：

  package com.weitoutiao.util;
  
  public class UserContext {
      private static final ThreadLocal<Integer> currentUserId = new ThreadLocal<>();
  
      public static void setCurrentUserId(Integer userId) {
          currentUserId.set(userId);
      }
      public static Integer getCurrentUserId() {
          return currentUserId.get();
      }
      public static void clear() {
          currentUserId.remove();
      }
  }
  

2. 创建JwtInterceptor

• 右键com.weitoutiao,新建java类：interceptor.JwtInterceptor

• interceptor.JwtInterceptor中的代码如下：

  package com.weitoutiao.interceptor;
  
  import com.weitoutiao.util.JwtUtil;
  import com.weitoutiao.util.UserContext;
  import jakarta.servlet.http.HttpServletRequest;
  import jakarta.servlet.http.HttpServletResponse;
  import org.springframework.beans.factory.annotation.Autowired;
  import org.springframework.stereotype.Component;
  import org.springframework.web.servlet.HandlerInterceptor;
  
  @Component
  public class JwtInterceptor implements HandlerInterceptor {
      @Autowired
      private JwtUtil jwtUtil;
  
      @Override
      public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
          String token = request.getHeader("Authorization");
          if (token != null && token.startsWith("Bearer ")) {
              token = token.substring(7);
              if (jwtUtil.validateToken(token)) {
                  Integer userId = jwtUtil.getUserIdFromToken(token);
                  UserContext.setCurrentUserId(userId);
                  return true;
              }
          }
          response.setStatus(401);
          response.setContentType("application/json;charset=utf-8");
          response.getWriter().write("{\"code\":401,\"message\":\"未登录或token失效\"}");
          return false;
      }
  
      @Override
      public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
          UserContext.clear();
      }
  }
  

3. 配置拦截器

• 右键config文件夹，新建java类：InterceptorConfig

• InterceptorConfig中的代码如下：

  package com.weitoutiao.config;
  
  import com.weitoutiao.interceptor.JwtInterceptor;
  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;
  
  @Configuration
  public class InterceptorConfig implements WebMvcConfigurer {
      @Autowired
      private JwtInterceptor jwtInterceptor;
  
      @Override
      public void addInterceptors(InterceptorRegistry registry) {
          registry.addInterceptor(jwtInterceptor)
                  .addPathPatterns("/**")
                  .excludePathPatterns("/user/login", "/user/register");
      }
  }
  

4.工程目录结构