跨域

前後端的分離
   跨域的痛點,平常工作中前端需要調用你本地或者測試的接口,未部署測試環境之前,需要本地調用測試,
   使用java一個類就可以解決,貼代碼：

package com.bs.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.HttpServletResponse;

public class CorsFilter implements Filter{

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

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
	     System.out.println("************************ 跨域過濾器 start ************************");
	        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");  
	        System.out.println("************************ 跨域過濾器 end ************************");
	        chain.doFilter(request, response);
		
	}

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

}

    另外需要在web.xml中配置filter攔截

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

    至此完美解決跨域問題。