SpringMVC_拦截器-编程知识

SpringMVC_拦截器

4.拦截器

4.1拦截器概述

概述：一种动态拦截方法调用的机制，在SpringMVC中动态拦截控制器方法的执行
实际开发中，静态资源（HTML/CSS）不需要交给框架处理，需要拦截的是动态资源

4.2图示

图示

4.3案例实现
模拟没有登录拦截操作

新定义拦截器

@Component
public class LoginInterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println("登录拦截操作");String username = request.getParameter("username");if("sy".equals(username)){return true;}System.out.println("preHandle");return false;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("postHandle");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("afterCompletion");}
}

修改SpringMvc 配置

@Configuration
@ComponentScan({"cn.sycoder.controller","cn.sycoder.interceptor"})
@EnableWebMvc
public class SpringMvcConfig implements WebMvcConfigurer {@AutowiredLoginInterceptor loginInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(loginInterceptor).addPathPatterns("/item","/item/*");}
}

controller 确实被拦截

@RestController
@RequestMapping("/item")
public class ItemController {@GetMapping("/{id}")public String getById(@PathVariable Long id){return "query"+id;}@GetMappingpublic String list(){return "list";}
}

4.4拦截器参数讲解

HttpServletRequest request
HttpServletResponse response
Object handler 相当于是对访问接口的一种包装

4.5拦截器链

新增拦截器

@Component
public class AuthInterceptor implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println("权限拦截的方法");return true;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("权限拦截的postHandle方法");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("权限拦截的afterCompletion方法");}
}

添加到拦截器链中

@Configuration
@ComponentScan({"cn.sycoder.controller","cn.sycoder.interceptor"})
@EnableWebMvc
public class SpringMvcConfig implements WebMvcConfigurer {@AutowiredLoginInterceptor loginInterceptor;@AutowiredAuthInterceptor authInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(loginInterceptor).addPathPatterns("/item","/item/*");registry.addInterceptor(authInterceptor).addPathPatterns("/item","/item/*");}
}