后端解决跨域问题

过滤器：

package com.shenke.filter;

import java.io.IOException;

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

import org.springframework.stereotype.Component;

@Component
public class CorsFilter implements Filter {

    public CorsFilter() {
        super();
        // TODO Auto-generated constructor stub
        System.out.println("过滤器启动...");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
            throws IOException, ServletException {
        // TODO Auto-generated method stub
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest req = (HttpServletRequest) servletRequest;
        // 注意：如果想要允许发送Cookie，那么Access-Control-Allow-Origin不能为"*"
        response.setHeader("Access-Control-Allow-Origin", req.getHeader("Origin"));
        response.setHeader("Access-Control-Allow-Credentials", "true");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE, PUT");
        response.setHeader("Access-Control-Max-Age", "3628800");
        response.setHeader("Access-Control-Allow-Headers", "*");
        response.setHeader("Access-Control-Expose-Headers", "Content-disposition");
        filterChain.doFilter(servletRequest, servletResponse);
    }

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // TODO Auto-generated method stub
    }

}