SprinbBoot之攔截器

springboot項目中，攔截器可以用作以下用途：

1. 用於登錄驗證；
2. 性能檢查；
3. 日誌記錄；

以登錄驗證爲例：

需要重寫一個攔截器、寫一個配置類

重寫攔截器代碼如下（攔截器在controller之前執行）

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginInterceptor implements HandlerInterceptor {
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        Object user = request.getSession().getAttribute("user");
        if (user == null){
            request.setAttribute("msg","當前沒有權限,請先登錄");
            request.getRequestDispatcher("/login").forward(request,response);
            return  false;//流程中斷
        }else {
            return true;//流程繼續
        }

    }
}

配置類代碼：addPathPatterns//這個是添加攔截路徑，excludePathPatterns這個是排除攔截的路徑多個路徑中間用逗號隔開

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //添加自定義攔截器，添加攔截路徑和排除攔截路徑
        registry.addInterceptor(new LoginInterceptor()).addPathPatterns("/**")
                .excludePathPatterns("/","/index.html","/login","/userLogin","/static/**");
    }

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
        WebMvcConfigurer.super.addResourceHandlers(registry);
    }

 
}

controller

@Controller
public class LoginController {

    @PostMapping("/userLogin")
    public String userLogin(String username, String password, Model model,HttpSession session){
        if (!StringUtils.isEmpty(username) && "123456".equals(password)){
            //記錄登錄狀態
            session.setAttribute("user",username);
            //跳轉到主頁
            return "redirect:main.html";
        }else {
            model.addAttribute("msg","用戶名或密碼錯誤");
            return "login";
        }
    }


}