Java：拦截器(Interceptor)

拦截器和过滤器之间的区别是什么? 

自定义拦截器

1. 创建拦截器类：让类实现HandlerInterceptor接口，重写接口中的三个方法

@Component
//定义拦截器类，实现HandlerInterceptor接口
public class ProjectInterceptor implements HandlerInterceptor {
    @Override
    //原始方法调用前执行的内容
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle...");
        return true;
    }
​
    @Override
    //原始方法调用后执行的内容
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle...");
    }
​
    @Override
    //原始方法调用完成后执行的内容
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion...");
    }
}

2. 配置拦截器类：在WebMvcConfigurer中注册该拦截器，并告诉spring哪些路径需要拦截，哪些路径不需要拦截

@Configuration
public class InterceperConfig implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //添加拦截器
        InterceptorRegistration interceptorRegistration = registry.addInterceptor(new ProjectInterceptor());
        //如下的路径不拦截，多个路径用逗号分隔
        interceptorRegistration.excludePathPatterns("/demo/test2");
        //拦截如下路径
        interceptorRegistration.addPathPatterns("/**");
    }
}

2.1. 配置多个拦截器

 拦截器的运行顺序