Many time I use to forget how to work inside a firewall/proxy enabled
environment, particularly when you using Terminal/Commandline. I use to
run apps outside of the IDE some time run java class in command prompt.
The app may try to connect internet or call some url etc. And you get
exception of Connection timeout or socket error etc. All we need to do
is make Java aware of Proxy IP and port!
When you work under a proxy and like to run your app in you have to setup the proxy setting for your Java app.
Java provides following way to work in a Proxy environment:
Proxy setup in Java provides both HTTP and HTTPs.
http.proxyHost – host name/ip of the proxy
http.proxyPort – port of the proxy
http.proxyPort – bypassing the direct accessport
For HTTPs: instead of http give https as prefix
System Property:
System class having property settings, through this you can enable proxy setting through programmatically
In your java code you may give inside a static block
System.setProperty("http.proxyHost", "<HOST>");
System.setProperty("http.proxyPort", "<PORT>");
To clear the setting use
System.clearProperty("http.proxyHost");
Command Line:
If you don’t like to hardcode in code you can use switch for your java command also as follows
$ java -Dhttp.proxyHost=<HOST> -Dhttp.proxyPort=<PORT> HelloWebWorld
