Java跨域设置

Access-Control-Allow-Origin 为允许哪些Origin发起跨域请求. 这里设置为”*”表示允许所有，通常设置为所有并不安全，最好指定一下。

Access-Control-Allow-Methods 为允许请求的方法.

Access-Control-Max-Age 表明在多少秒内，不需要再发送预检验请求，可以缓存该结果

Access-Control-Allow-Headers 表明它允许跨域请求包含content-type头，这里设置的x-requested-with ，表示ajax请求

<filter>
<filter-name>CrossOrigin</filter-name>
<filter-class>org.digdata.swustoj.filter.CrossOriginFilter</filter-class>
<init-param>
<param-name>AccessControlAllowOrigin</param-name>
<param-value>*</param-value>
</init-param>
<init-param>
<param-name>AccessControlAllowMethods</param-name>
<param-value>POST, GET, DELETE, PUT</param-value>
</init-param>
<init-param>
<param-name>AccessControlMaxAge</param-name>
<param-value>3628800</param-value>
</init-param>
<init-param>
<param-name>AccessControlAllowHeaders</param-name>
<param-value>x-requested-with</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CrossOrigin</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

package org.digdata.swustoj.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;

/**
*
* @author wwhhf
* @since 2016年5月30日
* @comment 跨域过滤器
*/
public class CrossOriginFilter implements Filter {

private FilterConfig config = null;

@Override
public void init(FilterConfig config) throws ServletException {
this.config = config;
}

@Override
public void destroy() {
this.config = null;
}

/**
*
* @author wwhhf
* @since 2016/5/30
* @comment 跨域的设置
*/
@Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletResponse httpResponse = (HttpServletResponse) response;
// 表明它允许"http://xxx"发起跨域请求
httpResponse.setHeader("Access-Control-Allow-Origin",
config.getInitParameter("AccessControlAllowOrigin"));
// 表明在xxx秒内，不需要再发送预检验请求，可以缓存该结果
httpResponse.setHeader("Access-Control-Allow-Methods",
config.getInitParameter("AccessControlAllowMethods"));
// 表明它允许xxx的外域请求
httpResponse.setHeader("Access-Control-Max-Age",
config.getInitParameter("AccessControlMaxAge"));
// 表明它允许跨域请求包含xxx头
httpResponse.setHeader("Access-Control-Allow-Headers",
config.getInitParameter("AccessControlAllowHeaders"));
chain.doFilter(request, response);
}

}