SpringBoot Interceptor快速上手

#快速上手

定义拦截器

创建的拦截器类需要继承HandlerInterceptor接口并实现其方法

@Component
public class DemoInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        response.setContentType("text/html");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write("该请求已成功通过拦截器");
        return false;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request,response,handler,modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

• preHandle在访问资源前进行，返回一个布尔类型的值，true为允许其访问资源，false为不允许其访问资源
• postHandle在访问资源后执行
• afterCompletion方法在视图渲染完毕后执行，是最后执行的

同时，为了方便我们注册拦截器，我们给它加上@Component注解交给IOC容器管理

注册拦截器

在注册拦截器前，需要创建一个配置类，继承WebMvcConfiguer接口并加上@Configuraion注解表明这是一个配置类。

重写其addInterceptors方法注册拦截器并设置拦截路径。

@Configuration
public class WebConfig implements WebMvcConfigurer {
    @Autowired
    DemoInterceptor demoInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(demoInterceptor).addPathPatterns("/**");
    }
}