Many times java programs need to connect the internet. If your application server is not allowed to connect the internet then you should use proxy to open a gateway to connect internet over proxy. At this post, I wrote a basic java code and also show how to set proxy configuration at JVM side from the command line.
Step 1: Compile Java Code for Connection Test
I added commands for the Linux server. But it's not different for other OS too. Same operation can be performed any kind of operating system which Java compiler installed.
- First Create a file which named "URLConnectionReader.java" under /tmp directory
#vi /tmp/URLConnectionReader.java
- Second add codes to file and save it.
import java.net.*;
import java.io.*;
public class URLConnectionReader {
public static void main(String[] args) throws Exception {
System.setProperty("javax.net.debug", "all");
System.setProperty("https.protocols", "TLSv1.1,TLSv1.2");
java.lang.System.setProperty(
"jdk.tls.client.protocols", "TLSv1,TLSv1.1,TLSv1.2");
URL bkmexpress = new URL(args[0]);
URLConnection yc = bkmexpress.openConnection();
BufferedReader in = new BufferedReader(
new InputStreamReader(
yc.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null)
System.out.println(inputLine);
in.close();
}
}
- Then last step compile java codes.
#/usr/java/jdk1.8.0_111/bin/javac /tmp/URLConnectionReader.java
Step 2: Test Connection With Proxy
-You need to run this command under where your "URLConnectionReader.class" file created. "URLConnectionReader.class" is the compiled file when you run javac command at step 1.
#/usr/java/jdk1.8.0_111/bin/java -Dhttp.proxyHost=casesupproxysrv01 -Dhttp.proxyPort=8080 URLConnectionReader http://casesup.com
