springboot：拦截器

自定义一个拦截器实现HandlerInterceptor接口，然后创建一个配置类实现WebMvcConfigurer接口，用配置类的addInterceptor方法向容器中添加拦截器。

自定义拦截器

package com.example.boot2admin.config;

import org.springframework.web.servlet.HandlerInterceptor;

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

public class LoginInterceptor implements HandlerInterceptor {

    @Override
    //登陆前的身份验证
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        HttpSession session = request.getSession();
        //获取session
        if(session.getAttribute("LoginUser")!=null){
            return true;
        }
        else {
        //这里用session和model传不了值
        //所以只能用req
            request.setAttribute("msg","请先登录");
            request.getRequestDispatcher("/").forward(request,response);
            return false;
        }

    }
}

自定义配置类

package com.example.boot2admin.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class Config implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginInterceptor())//向容器中添加拦截器
                .addPathPatterns("/**")//配置拦截路径 拦截全部 包括静态资源
                .excludePathPatterns("/","/login","/js/**","/css/**","/fonts/**","/images/**");
                //静态资源放行
    }
}