SpringMVC_拦截器

news2025/2/28 12:58:23

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 {
    @Override
    public 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;
    }

    @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");
    }
}

修改SpringMvc 配置

@Configuration
@ComponentScan({"cn.sycoder.controller","cn.sycoder.interceptor"})
@EnableWebMvc
public class SpringMvcConfig implements WebMvcConfigurer {

    @Autowired
    LoginInterceptor loginInterceptor;

    @Override
    public 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;
    }

    @GetMapping
    public 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 {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("权限拦截的方法");
        return true;
    }

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

    @Override
    public 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 {

    @Autowired
    LoginInterceptor loginInterceptor;

    @Autowired
    AuthInterceptor authInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor).addPathPatterns("/item","/item/*");
        registry.addInterceptor(authInterceptor).addPathPatterns("/item","/item/*");
    }
}