在HTML用ajax跨域访问请求时报错：

Access to XMLHttpRequest at ‘http://192.168.2.1:8080/portal/studentController.do?saveUserInfo’ from origin ‘http://oa.51.cn:3808’ has been blocked by CORS policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource.

解决办法

1、新建个过滤器

package org.jeecgframework.core.filter;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class CORSFilter implements Filter {

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		
	}

	@Override
	public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
			throws IOException, ServletException {
		HttpServletResponse response = (HttpServletResponse) servletResponse;  
        response.setHeader("Access-Control-Allow-Origin", "*");  
        response.setHeader("Access-Control-Allow-Methods", "GET,POST,HEAD,PUT,DELETE");  
        response.setHeader("Access-Control-Max-Age", "3600");  
        response.setHeader("Access-Control-Allow-Headers", "Accept,Origin,X-Requested-With,Content-Type,X-Auth-Token");  
        response.setHeader("Access-Control-Allow-Credentials", "true");  
		chain.doFilter(servletRequest, servletResponse);
	}

	@Override
	public void destroy() {
		
	}

}

2、在web.xml中配置

	<!-- CORS 解决跨域请求问题-->
	<filter>
		<filter-name>CorsFilter</filter-name>
		<!--你过滤器的包 -->
		<filter-class>org.jeecgframework.core.filter.CORSFilter</filter-class>
	</filter>
	<filter-mapping>
		<filter-name>CorsFilter</filter-name>
		<!-- 你开放的接口前缀-->
		<url-pattern>/*</url-pattern>
	</filter-mapping>