这里的错误是过滤器尚未通过 addMappingForUrlPatterns 方法配置URL路径。

The bug here is that the filter hasn't been configured with a URL path via the addMappingForUrlPatterns method.

这对我来说使用了dropwizard 0.7 .1：

This worked for me using dropwizard 0.7.1:

import org.eclipse.jetty.servlets.CrossOriginFilter;
import javax.servlet.DispatcherType;
import java.util.EnumSet;

public void run(Configuration conf, Environment environment)  {
    // Enable CORS headers
    final FilterRegistration.Dynamic cors =
        environment.servlets().addFilter("CORS", CrossOriginFilter.class);

    // Configure CORS parameters
    cors.setInitParameter("allowedOrigins", "*");
    cors.setInitParameter("allowedHeaders", "X-Requested-With,Content-Type,Accept,Origin");
    cors.setInitParameter("allowedMethods", "OPTIONS,GET,PUT,POST,DELETE,HEAD");

    // Add URL mapping
    cors.addMappingForUrlPatterns(EnumSet.allOf(DispatcherType.class), true, "/*");
}

我假设你在浏览器中测试这个，但是你可以通过CLI验证如下curl命令：

I'm assuming you're testing this live in a browser, but you can verify via CLI with a curl command like this:

$ curl -H "Origin: http://example.com" \
       -H "Access-Control-Request-Method: POST" \
       -H "Access-Control-Request-Headers: X-Requested-With" \
       -X OPTIONS --verbose \
       http://localhost:8080

你应该看到一个一堆访问控制 - * 响应中的HTTP标头。

You should see a bunch of Access-Control-* HTTP headers in the response.