可以使用
ProxySelector类检测代理，并通过使用
System类的
setProperty方法分配环境变量来分配系统代理：
System.setProperty("java.net.useSystemProxies", "true");System.out.println("detecting proxies");List l = null;try { l = ProxySelector.getDefault().select(new URI("http://foo/bar"));} catch (URISyntaxException e) { e.printStackTrace();}if (l != null) { for (Iterator iter = l.iterator(); iter.hasNext();) { java.net.Proxy proxy = (java.net.Proxy) iter.next(); System.out.println("proxy type: " + proxy.type()); InetSocketAddress addr = (InetSocketAddress) proxy.address(); if (addr == null) { System.out.println("No Proxy"); } else { System.out.println("proxy hostname: " + addr.getHostName()); System.setProperty("http.proxyHost", addr.getHostName()); System.out.println("proxy port: " + addr.getPort()); System.setProperty("http.proxyPort", Integer.toString(addr.getPort())); } }}
