跨域问题:
response.setHeader(“Access-Control-Allow-Origin”, “*”);
response.setHeader(“Access-Control-Allow-Methods”, “POST, GET, OPTIONS, DELETE”);
response.setHeader(“Access-Control-Allow-Headers”, “x-requested-with”);
在服务器端加上以上代码就可以了,主要是第一行允许其它域名的访问。
session失效问题:
在我们每一次的数据请求中,浏览器都会向后台发送一个JSession,后台会根据这个值自动查找Id为JSession的那个session对象。但是当跨域时,JSession的值每次都会改变,后台就会以为是新的一个会话打开,于是又去创建了一个新的Session对象,而原来的Session对象就找不到了。
当我们登录成功后保存一个token到session中去,下一个请求来的时候又会重建一个session,原来的session就取不到了,于是还是未登录状态。解决这个问题只要在跨域问题的代码上加上这句就可以了:
response.setHeader(“Access-Control-Allow-Credentials”,”true”); //是否支持cookie跨域
配置了allow-credentials之后,如果allow-origin设为*
,跨域时会报错说因为允许credentials,origin不能设为通配*
,那么就设置为当前domain。
response.setHeader(“Access-Control-Allow-Origin”, request.getHeader(“Origin”));
ok,后台开启Credentials后,前端也要配合开启,angular里app.config的时候加上这句就行了:
$httpProvider.defaults.withCredentials = true;
后台代码可以放在一个自定义filter里:
public class DefaultFilter implements Filter {
private String encoding;
public void init(FilterConfig config) throws ServletException {
this.encoding = config.getInitParameter("encoding");
}
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) req;
HttpServletResponse response = (HttpServletResponse) res;
req.setCharacterEncoding(encoding);
response.setContentType("text/html;charset=" + encoding);
response.setHeader("Pragma","No-cache");
response.setHeader("Cache-Control","no-cache");
response.setDateHeader("Expires", 0);
response.setHeader("Access-Control-Allow-Origin", request.getHeader("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");
response.setHeader("Access-Control-Allow-Credentials","true"); //是否支持cookie跨域
chain.doFilter(req, res);
}
public void destroy() {}
}
在web.xml配上这个filter即可:
<filter>
<filter-name>encodingFilter</filter-name>
<filter-class>com.xxx.xxx.filter.DefaultFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>utf-8</param-value>
</init-param>
</filter>