$.ajax({
	    type: "POST",
	    headers: { 
		Accept: "application/json; charset=utf-8", 
		Token: "xxx"  //這個是自定義的請求頭
		},
	    url: "XXX",
	    contentType: "application/json", 
	    data: JSON.stringify(str),//將變數str轉為json資料，可忽略
	    dataType: 'json',
	    success: function(result) {
	        if(result.code == 200) {//200：請求成功
	        	consile.log("ok");
	        } 
	    }
	});
 

 下面是過濾器的一個設定

@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {

        res.setHeader("Access-Control-Allow-Headers", "Content-Type,Token");

        //自定義跨域請求瀏覽器會先發送一個OPTIONS請求，伺服器要對其作出相應，瀏覽器才會正常發出請求
        if (req.getMethod().equals("OPTIONS")) {
			//設定響應狀態碼
			res.setStatus(200); 
            return;
        }
}
 

 到這裡完成了配置

 例項

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
			throws IOException, ServletException {
		request.setCharacterEncoding("utf-8");
		response.setCharacterEncoding("utf-8");
		
		HttpServletResponse res = (HttpServletResponse) response;
		HttpServletRequest req = (HttpServletRequest) request;
		res.setHeader("Access-Control-Allow-Origin", "*");
		res.setHeader("Access-Control-Allow-Credentials", "true");//是否允許傳送Cookie
		res.setHeader("Access-Control-Allow-Methods", "*");
		res.setHeader("Access-Control-Allow-Headers", "Content-Type,Access-Token");
		//對客戶端自定義請求頭的應答
		res.setHeader("Access-Control-Allow-Headers", "Content-Type,Token");
		
		/**
		 * 針對自定義header問題
		 * 客戶端錯誤:Request header field Token is not allowed by Access-Control-Allow-Headers in preflight response.
		 * 原因:包含自定義header欄位的跨域請求，瀏覽器會先向伺服器傳送OPTIONS請求，探測該伺服器是否允許自定義的跨域欄位。
		 * 		如果允許，則繼續實際的POST／GET正常請求，否則，返回標題所示錯誤。
		 */
		if (req.getMethod().equals("OPTIONS")) {
			//設值響應狀態碼
			res.setStatus(200); 
                    return;
                }
		chain.doFilter(request, response);
	}