Spring Boot 编写一个拦截器

创建一个类并使其实现接口HandlerInterceptor

接口提供了一个请求的三个周期的拦截方法

在controller之前，返回true则放行，false反之,handler包含处理请求的controller类以及其方法

• boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)

在controller接受请求之后，contorller渲染视图之前，如果发生异常就不执行了,可对ModelAndView操作

• void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)

在controller处理全部完成之后,ex参数包含处理期间发生的异常,但仅为未被全局捕获的异常

• void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)

public class TheInterceptor implements HandlerInterceptor {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion");
    }
}

编写完成后需要将其注册进处理栈中才会生效, 创建WebMvcConfigurer的实现类

@Configuration
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new MyInterceptor())
                // 需要拦截的路径,默认全部拦截
                .addPathPatterns("/test1")
                // 需要排除的路径
                .excludePathPatterns("/test2");
    }
}