拦截器+自定义注解验证 Token 登录

背景：

最近做的项目中使用了token验证用户登录状态，用户每次请求都需要验证token，出现重复代码，所以想着用拦截器+自定义注解来验证，将验证token 的代码放在自定义拦截器中，如果验证成功则返回 true 放行，如果验证失败则返回 false 程序运行终止，但是验证失败我是要返回给前端错误信息的，具体怎么实现直接看代码。

 

代码：

1. MyInterceptor 实现 HandlerInterceptor

@Component
public class MyInterceptor implements HandlerInterceptor {

    @Autowired
    private UserLoginDAO userLoginDAO;

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

        TokenAuthenticate annotation = ((HandlerMethod) handler).getMethodAnnotation(TokenAuthenticate.class);
        // 没有添加注解
        if (annotation == null){
            return true;
        }else {
            // 添加了注解
            // 取出token
            String parameter = request.getParameter("json");
            JSONObject jsonObject = JSONObject.parseObject(parameter);
            Integer userId = Integer.valueOf(jsonObject.getString("userId"));
            String token = jsonObject.getString("token");
            UserLogin ul = new UserLogin();
            ul.setUserId(userId);
            UserLogin userLogin = userLoginDAO.selectOne(ul);
            if (userLogin != null && userLogin.getToken().equals(token)){
                return true;
            }else {
                printJson(response);
                return false;
            }
        }
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }

    private static void printJson(HttpServletResponse response) {
        String content = JSON.toJSONString(BaseApiService.setErrorResult("登录失效，请重新登录"));
        printContent(response, content);
    }

    private static void printContent(HttpServletResponse response, String content) {
        try {
            response.reset();
            response.setContentType("application/json");
            response.setHeader("Cache-Control", "no-store");
            response.setCharacterEncoding("UTF-8");
            PrintWriter pw = response.getWriter();
            pw.write(content);
            pw.flush();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

2. InterceptorConfig 继承 WebMvcConfigurerAdapter   这里主要是为了MyInterceptor中DAO的注入，如果MyInterceptor中没有注入DAO那么这个InterceptorConfig可以不要，因为有自定义注解。

@Configuration
public class InterceptorConfig extends WebMvcConfigurerAdapter {

    @Bean
    public HandlerInterceptor getMyInterceptor(){
        return new MyInterceptor();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        InterceptorRegistration interceptor = registry.addInterceptor(getMyInterceptor());
    }
}

3. TokenAuthenticate 自定义注解

@Documented
@Target({ ElementType.METHOD, ElementType.TYPE })
@Retention(RetentionPolicy.RUNTIME)
@Component
public @interface TokenAuthenticate {

}