ajax请求，跨域问题，在Java客户端中解决

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/u014621467/article/details/72730871

1. 在controller中添加如下代码，这种办法，时灵时不灵，可以尝试下：

        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with");
         或：
        response.addHeader("Access-Control-Allow-Origin", "*");
        response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
        response.addHeader("Access-Control-Allow-Headers", "Content-Type");

1. 另外一种方法是在配置文件中统一配置，这样似乎更有效，而且不用在每个controller中的方法中都重复写，更方便。
   来自博客http://m.blog.csdn.net/article/details?id=51418384
   在项目任意路径下新建一个类CORSFilter.java

   public class CORSFilter implements Filter {
       public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
           HttpServletResponse response = (HttpServletResponse) res;
           response.setHeader("Access-Control-Allow-Origin", "*");
           response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
           response.setHeader("Access-Control-Max-Age", "3600");
           response.addHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
           chain.doFilter(req, res);
       }
       public void init(FilterConfig filterConfig) {}
       public void destroy() {}
   }
   

在web.xml文件中添加如下代码：

<filter>
        <filter-name>cors</filter-name>
        <filter-class>xxxx.CORSFilter</filter-class>
</filter>
<filter-mapping>
         <filter-name>cors</filter-name>
         <url-pattern>/*</url-pattern>
</filter-mapping>