如果Java的http代理关闭，它将恢复为非代理 [英] If Java's http proxy is down, it reverts to non-proxy

问题描述

这真是出乎意料的行为。我正在使用JavaFX WebView <编写简单的Web浏览器/ A>。为了使Web请求通过本地代理，我写了类似的代码：

This is really unexpected behavior. I'm writing a simple web browser using the JavaFX WebView. To make the web requests go through a local proxy, I wrote code similar to this:

System.setProperty("http.proxyHost", "localhost");
System.setProperty("http.proxyPort", "8080");

如果代理正在运行，它似乎工作正常。但是，如果不是，Java会默默地恢复为不使用代理！如果代理不可用，如何强制Java失败？

It appears to work fine if the proxy is running. However, if it isn't, Java silently reverts to not using a proxy at all! How can I force Java to fail if the proxy is not available?

推荐答案

您可以使用自定义 ProxySelector 只允许你的代理，并且不提供 Proxy.NO_PROXY 作为替代：

You may be able to do this with a custom ProxySelector which only allows your proxy, and doesn't offer Proxy.NO_PROXY as an alternative:

import java.net.*;
import java.util.*;

public class AlwaysProxySelector implements ProxySelector {
  private List<Proxy> proxies = Arrays.asList(new Proxy[] {
        new Proxy(Proxy.Type.HTTP, new InetSocketAddress("localhost", 8080))
      });

  public List<Proxy> select(URI u) { return proxies; }
  public void connectFailed(URI u, SocketAddress a, IOException e) {}
}

使用 ProxySelector.setDefault（new AlwaysProxySelector（））安装此选择器;

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