一个CORS实现跨域的过滤器

package com.grain.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;

public class CORSFilter implements Filter {
    
	@Override
	public void init(FilterConfig arg0) throws ServletException {
		// TODO Auto-generated method stub
		
	}
	@Override
	public void destroy() {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void doFilter(ServletRequest req, ServletResponse res, FilterChain filterChain)
			throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;
        HttpServletResponse response = (HttpServletResponse) res;
		response.addHeader(\"Access-Control-Allow-Origin\", \"*\");
        response.addHeader(\"Access-Control-Allow-Methods\", \"GET, POST, PUT, DELETE\");
        response.addHeader(\"Access-Control-Allow-Headers\", \"Content-Type\");
        response.addHeader(\"Access-Control-Max-Age\", \"1800\");//30 min
        filterChain.doFilter(request, response);
		
		
	}

	
}

web. 配置 

<filter>
  	<filter-name>CORSFilter</filter-name>
  	<filter-class>com.grain.filter.CORSFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>CORSFilter</filter-name>
  	<url-pattern>/*</url-pattern>
  </filter-mapping>