相关疑难解决方法(0)

我有一个由Tomcat托管的静态网站.

如何为我的网站设置标题,如:Access-Control-Allow-Origin: *

它们都是静态文件,而不是任何servlet应用程序.

我想启用tomcat CORS过滤器,我将其添加到web.xml:

<filter>
    <filter-name>CorsFilter</filter-name>
    <filter-class>org.apache.catalina.filters.CorsFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>CorsFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

但它不起作用.我尝试使用自定义过滤器:

<filter>
    <filter-name>SimpleCORSFilter</filter-name>
    <filter-class>com.common.SimpleCORSFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>SimpleCORSFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

有了这个班级:

public class SimpleCORSFilter implements Filter {

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) res;
        response.setHeader("Access-Control-Allow-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");
        chain.doFilter(req, res);
    }
}

这很好用,你能告诉我为什么吗？我不知道它是否重要但我使用Spring Framework.

当我在将视频上传到服务器之前尝试获取屏幕截图并将其另存为PNG时,我遇到了以下问题

我希望你能解决我的问题......

/*Output image show view*/
$('#file_browse').change(function(e){
    getVideo(this);
});

var capbtn = document.querySelector('#video_capture');
var video = document.querySelector('video');
var canvas = document.querySelector('canvas');
var context = canvas.getContext('2d');
var w, h, ratio;

video.addEventListener('loadedmetadata', function() {
    ratio = video.videoWidth / video.videoHeight;
    w = video.videoWidth - 100;
    h = parseInt(w / ratio, 10);
    canvas.width = w;
    canvas.height = h;           
}, false);

capbtn.addEventListener("click", function(){
    context.fillRect(0, 0, w, h);
    context.drawImage(video, 0, 0, w, h);
    var objImageData = canvas.toDataURL("data:image/png;");  
});

function getVideo(input) {
    if (input.files && input.files[0]) { …