服务端SpringBoot2.x   ：localhost:8082

前端Vue2.x                 ：localhost:81

前后端的端口号不同，为跨域，导致前端访问后端时，每次访问都新生产一个sessionID。解决如下：

 

后端：

1.添加过滤器：

package com.nsoft.gkzp.syscore.config.filter;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebFilter(urlPatterns = "/*", filterName = "corsFilter")
public class CorsFilter implements Filter {

    final private static Logger logger = LogManager.getLogger(CorsFilter.class);
    @Override
    public void destroy() {
    }
    /**
     * 此过滤器只是处理跨域问题
     * @param servletRequest
     * @param servletResponse
     * @param chain
     * @throws ServletException
     * @throws IOException
     */
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws ServletException, IOException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        String origin = request.getHeader("Origin");
        if(origin == null) {
            origin = request.getHeader("Referer");
        }
        response.setHeader("Access-Control-Allow-Origin", origin);// 允许指定域访问跨域资源(这里不能写*，*代表接受所有域名访问，如写*则下面一行代码无效。谨记)
        response.setHeader("Access-Control-Allow-Credentials", "true");//true代表允许客户端携带cookie(此时origin值不能为“*”，只能为指定单一域名)
        response.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, DELETE, TRACE, OPTIONS, PATCH"); /// 允许浏览器在预检请求成功之后发送的实际请求方法名
        response.setHeader("Access-Control-Allow-Headers", "Authorization,Origin, X-Requested-With, Content-Type, Accept,Access-Token");// 允许浏览器发送的请求消息头
        //response.setHeader("Access-Control-Max-Age", "86400");            // 浏览器缓存预检请求结果时间,单位:秒

        chain.doFilter(request,response);
    }
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }


}

2. springboot2.配置过滤器时，启动类必须加上@ServletComponentScan才会加载过滤器

package com.nsoft.gkzp;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.server.ConfigurableWebServerFactory;
import org.springframework.boot.web.server.ErrorPage;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.context.annotation.Bean;
import org.springframework.http.HttpStatus;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

/**
 * springboot入口
 * MapperScan("c