Ajax跨域后台处理

页面报错： Failed to load http://localhost:8080/websites/webInterface/queryNewsList: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://127.0.0.1:8020' is therefore not allowed access.


package com.xxx.websites.commons.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.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.httpclient.HttpStatus;

/**
 * 
 * @ClassName:CorsFilter
 * @Description:TODO(统一处理跨域请求)
 * @author: xxx
 * @date 2018年7月4日 上午11:11:19
 *
 * @Copyright: 2018 www.zsplat.com Inc. All rights reserved.
 */
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 _response = (HttpServletResponse) response;
        HttpServletRequest _request = (HttpServletRequest) request;
        // 指定允许其他域名访问
        _response.setHeader("Access-Control-Allow-Origin", "*");
        // 响应类型
        _response.setHeader("Access-Control-Allow-Methods", "POST, GET, DELETE, OPTIONS, DELETE");
        // 响应头设置
        _response.setHeader("Access-Control-Allow-Headers", "Content-Type, x-requested-with, X-Custom-Header, HaiYi-Access-Token");
        if ("OPTIONS".equals(_request.getMethod())){
            _response.setStatus(HttpStatus.SC_NO_CONTENT);
        }
        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {
    }
}

web.xml中配置　

<!-- 跨域拦截器 -->
    <filter>
        <filter-name>cors</filter-name>
        <filter-class>com.zsplat.websites.commons.filter.CorsFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>cors</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <!-- 跨域拦截器 -->