Java / Jetty：如何向嵌入式 Jetty 添加过滤器

Java / Jetty: How to Add Filter to Embedded Jetty

提问by David Williams

I am working with embedded Jetty and I want to add a servlet filter to check for authentication before each request. I tried following this examplebut it looks like the signature has changed.

我正在使用嵌入式 Jetty，我想在每个请求之前添加一个 servlet 过滤器来检查身份验证。我尝试遵循此示例，但看起来签名已更改。

<dependency>
    <groupId>org.eclipse.jetty</groupId>
    <artifactId>jetty-server</artifactId>
    <version>9.0.4.v20130625</version>
</dependency>

My Jetty starter looks like this:

我的 Jetty 启动器看起来像这样：

public class JettyStarter {

    public static void main( final String[] args ) throws Exception {
        Server server = new Server(8080);
        final ServletHolder servletHolder = new ServletHolder(new CXFServlet());
        final ServletContextHandler context = new ServletContextHandler();
        context.setContextPath("/");
        // context.addFilter(AuthenticationFilter.class, "/*", FilterMapping.REQUEST);
        context.addServlet(servletHolder, "/platform/*");
        context.addEventListener(new ContextLoaderListener());
        context.setInitParameter("contextClass", AnnotationConfigWebApplicationContext.class.getName());
        context.setInitParameter("contextConfigLocation", Config.class.getName());
        server.setHandler(context);
        server.start();
        server.join();
    }
}

When I uncomment the line

当我取消注释该行时

// context.addFilter(AuthenticationFilter.class, "/*", FilterMapping.REQUEST);

I find that the signature has changed. So I want to take a small step back and ask, with embedded Jetty, how do I add a filter that runs at the beginning of the request and allows the request to continue only if some condition is met?

我发现签名变了。所以我想退一步问，使用嵌入式 Jetty，如何添加一个在请求开始时运行的过滤器，并仅在满足某些条件时才允许请求继续？

The beginning of the AuthenticationFilter class looks like this:

AuthenticationFilter 类的开头如下所示：

import javax.servlet.*;
import java.io.IOException;

public class AuthenticationFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {}

    @Override
    public void doFilter(ServletRequest servletRequest, 
                         ServletResponse servletResponse, 
                         FilterChain filterChain) throws IOException, ServletException {}

    @Override
    public void destroy() {}

}

采纳答案by Andrew

You are probably looking for EnumSet.of(DispatcherType.REQUEST), included a full example below:

您可能正在寻找EnumSet.of(DispatcherType.REQUEST)，包括下面的完整示例：

import java.io.IOException;
import java.util.EnumSet;

import javax.servlet.DispatcherType;
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.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletHandler;

public class JettyFilter {

  public static void main(final String[] args) throws Exception {
    Server server = new Server(8080);

    ServletHandler handler = new ServletHandler();
    server.setHandler(handler);

    handler.addServletWithMapping(HelloServlet.class, "/*");
    handler.addFilterWithMapping(HelloPrintingFilter.class, "/*",
        EnumSet.of(DispatcherType.REQUEST));

    server.start();
    server.join();
  }

  public static class HelloServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
      response.setContentType("text/html");
      response.setStatus(HttpServletResponse.SC_OK);
      response.getWriter().println("<h1>Hello SimpleServlet</h1>");
    }
  }

  public static class HelloPrintingFilter implements Filter {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
        throws IOException, ServletException {
      System.out.print("hello from filter");
    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {

    }

    @Override
    public void destroy() {}
  }
}