Are HTTP and HTTPS default port numbers defined in

问题:

I've hunted around a bit trying to see if port 80 and port 443 are defined as public constants anywhere. Do these exist in the JDK (or perhaps in a common library such as Apache HttpClient)?

回答1:

Look at Javadoc for URL: http://docs.oracle.com/javase/8/docs/api/java/net/URL.html#getDefaultPort--

getDefaultPort() returns the port for the given protocol

URL url = new URL("http://blah.com");
int defaultPort = url.getDefaultPort();

回答2:

Apache HttpClient does have them as integer constants:

• http://hc.apache.org/httpclient-3.x/apidocs/org/apache/commons/httpclient/HttpURL.html#DEFAULT_PORT
• http://hc.apache.org/httpclient-3.x/apidocs/org/apache/commons/httpclient/HttpsURL.html#DEFAULT_PORT