SpringBoot：自定义拦截器

秒速五厘米 2022-04-24 13:12 220阅读 0赞

## 一：理论实现 ##

*  实现接口-HandlerInterceptor，重写其中的三个方法
 *  实现接口WebMvcConfigurer，重写addInterceptors方法，注册拦截器

## 二：实战 ##

*  书写我自己的拦截器

@Component
    public class MyInterceptor implements HandlerInterceptor { 
        //请求处理前，也就是访问Controller前
        @Override
        public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { 
            String num = request.getParameter("num");
            if(num==null){ 
                System.out.println("被拦截器拦截了");
                return false;
            }else { 
                return true;
            }
        }
        //请求已经被处理，但在视图渲染前
        @Override
        public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { 
            System.out.println("请求处理结束了");
        }
        //请求结果结果已经渲染好了，response没有进行返回但也无法修改reponse了（一般用于清理数据）
        @Override
        public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { 
        }
    }

*  书写配置类

@Configuration
    public class MyConfig implements WebMvcConfigurer { 
        @Autowired
        private MyInterceptor myInterceptor;
    
        @Override
        public void addInterceptors(InterceptorRegistry registry) { 
            // 通过registry来注册拦截器，通过addPathPatterns来添加拦截路径
            registry.addInterceptor(this.myInterceptor).addPathPatterns("/**");
        }
    }

*  编写controller进行测试

@RestController
    public class TestController { 
        @GetMapping("hi")
        public String testController(){ 
            System.out.println("我正在处理请求");
            return "这是一个拦截器测试类";
        }
    }