前后端分离，java服务端解决跨域问题

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 request, ServletResponse response, FilterChain chain) throws IOException,

            ServletException {

        HttpServletResponse res = (HttpServletResponse) response;

        res.setContentType("text/html;charset=UTF-8");

        res.setHeader("Access-Control-Allow-Origin", "*");

        res.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");

        res.setHeader("Access-Control-Max-Age", "0");

        res.setHeader("Access-Control-Allow-Headers",
                "Origin, No-Cache, X-Requested-With, If-Modified-Since, Pragma, Last-Modified, Cache-Control, Expires, Content-Type, X-E4M-With,userId,token");

        res.setHeader("Access-Control-Allow-Credentials", "true");

        res.setHeader("XDomainRequestAllowed", "1");

        chain.doFilter(request, response);

    }

    public void destroy() {

    }

}

    <filter>
        <filter-name>cors</filter-name>
        <filter-class>com.dnn.filters.CorsFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>cors</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    

jfinal 的话一定要放在JFinalFilter上面