登陆拦截器

什么是拦截器

Spring MVC中的拦截器（Interceptor）类似于Servlet中的过滤器（Filter），它主要用于拦截用户请求并作相应的处理。例如通过拦截器可以进行权限验证、记录请求信息的日志、判断用户是否登录等。

return true 放行

import com.wq.myweb.pojo.Login;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * @Author:wuqi
 * @DATE: 2020/10/8 0008
 * @TIME: 10:19
 * @PROJECT_NAME: MyWeb
 */

@Component
public class LoginHandlerInterceptor implements HandlerInterceptor {
    //执行方法前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

        Login user = (Login)request.getSession().getAttribute("userck");
        if (user==null){
            System.out.println("不放行");
            response.sendRedirect("/login/ERRO");
            return false;
        }else {
            System.out.println("放行");
            return true;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

    }

前台内容不做拦截，后台只有登陆了才能跳到管理界面

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

/**
 * @Author:wuqi
 * @DATE: 2020/10/8 0008
 * @TIME: 10:36
 * @PROJECT_NAME: MyWeb
 */
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
    @Autowired
    private LoginHandlerInterceptor loginHandlerInterceptor;

    //这个方法是用来配置静态资源的，比如html，js，css，等等
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/static/**");
    }
    //注册拦截器
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        // 添加拦截的请求，并排除几个不拦截的请求        registry.addInterceptor(loginHandlerInterceptor).addPathPatterns("/manageArticles/**","/manageMedia/**","/manageNotice","/manageVisit/**","/manageComments/**","/password/**")
        .excludePathPatterns("/article/**","/login/**");
    }
}